Northern Nut Growers Association Thirty-Fourth Annual Report 1943
Author: Various
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If heartnuts have a future, which seems almost inevitable, it looks as though Canada, if it continues as it has started, will be one of the main sources of supply for varieties. The Canadians are doing a creative job.

THE SOUTHERN AREA. There are no nurserymen who report from the southern area. Practically all are interested in the production of nuts, but they are more alive than their northern neighbors to the value of timber, and more of them count upon it for a part of their profit from the planting of nut trees.

Interest is about equally divided between methods of propagation, grafting, budding, top-working, planting seed of better varieties, artificial cross-pollination, and searching their neighborhoods for wild trees that show promise of superiority.

The species being planted experimentally or commercially are, in order of precedence, black walnut, persimmon, pecan, Persian walnut, Chinese chestnut, hickories, filberts, hazels, heartnuts, Jap chestnuts, almonds, mulberry, native chestnuts, Jap walnuts, pawpaws and beech. Species of wild trees found locally follow closely the pattern of planting mentioned above, which is as it should be.

Climatic conditions are, in-general, favorable. Peaches are in most places reliably hardy. Lowest temperatures normally expected range from 22 deg. above to 20 deg. below zero; and the highest normal summer temperatures range from 90 deg. to 115 deg.. Dates of normal late spring frosts have a very wide spread, being all the way from March 1 to May 12. Normal early frost expectancy is from Oct. 10 to Nov. 15. All long-season crops mature well. The chief climatic enemies are drought and hot, dry winds.

As to growth conditions, clay soils predominate, but with plenty of loamy bottom land for nut planting. Acid soils predominate somewhat over lime soils, growing more unfavorably alkaline in the south-west.

Cultural practices are generally the same as in the north, but with a greater proportionate use of mowing and mulching, no doubt induced by the need for protection against greater heat, as well as for conservative of moisture. A greater proportionate failure of young trees to start first year's growth is also probably due to heat injury in the spring and summer following planting. Tree wrapping seems to be the corrective chiefly indicated.

The difficulties principally mentioned with matured trees are again mostly climatic; drought, sun-scald, early advent of spring followed by late frosts, delayed dormancy in the fall, poor filling in dry seasons, and biennial fruiting.

Insect enemies which damage both trees and nuts are practically the same as in the north only there are more of them. Rodent damage and squirrel theft seem less troublesome there owing, perhaps, to protective measures and to the well developed hunting instinct among southern farm boys.

A larger proportion of growers than are reported in the north sell nuts commercially, with pecans, walnuts, and chestnuts listed as the most profitable species. The practice is still limited as an important source of income, but a much greater proportion of planters look confidently forward toward profitable operations in the future.

Black Walnuts. It is evident that in some of the warmer parts of the United States, California, for instance, the word "hardiness" takes on a certain connotation that we should understand better in the north. Its meaning there is "resistance to delayed dormancy", as one California report states it. As a matter of fact, it might be advisable for us all everywhere to think of hardiness in these terms. Delayed dormancy is hazardous in any tree, whether natural to it or induced artificially by late summer or early fall cultivation and fertilizing, and whether the tree is located in the north or in the south. When a tree goes into the winter with sappy wood, it is injured, and we say it is not hardy.

That this is true in the south as well as in the north is well attested by the returns on black walnut trees of the south. There, the tree gives us a picture surprisingly similar to that of the north. In the south, if the tree's dormancy is delayed, it does not get its proper rest between crops and it dies or is stunted, in one way or another, for some time thereafter. In the north, if the following winter is severe, it simply dies. Perhaps the winter killed it. Or perhaps we killed it with unseasonable pampering.

Reports show that in the south, Rohwer, Stambaugh, and Ten Eyck lead in hardiness in the printed list of black walnuts, with a score of 80% each. Ohio, Stabler and Thomas each average 75%. Of the written-in names, Sifford and Beck are reported hardy, followed by Creitz. Elmer Myers has only one report, which is rather unfavorable in this respect.

In yield, Creitz has the best rating, then Thomas, Stambaugh, Sifford, Stabler and Beck, in that order.

Thomas is the most precocious in early bearing. One report has it that Thomas kills itself, sometimes, by overdoing it in this respect. Stabler, Sifford, Creitz and Beck come next. All of these varieties are reported as having well filled nuts, with Stabler in the lead, which may come as a surprise to many. Other qualities, such as husking and cracking, size, and quality of kernel, are reported to be the same as in the north except that Stabler leads in cracking quality, with Thomas a rather poor second, owing, perhaps, to a shell too well filled for cracking without shattering the kernels.

Seedling Chestnuts. More Chinese chestnuts are planted than Japs. They are hardier, yield better crops, are more precocious, and have a far better quality of kernel. The Japs excel only in size.

Named Chestnuts. Hobson is hardy and an extremely precocious bearer of finest quality. Carr follows. Reports on these varieties, however, are not numerous enough to enable one to reach a satisfactory appraisal. Two Marron strains are mentioned as producers of very large nuts; otherwise this variety's record is not impressive.

Pecans. Posey and Greenriver are given top mention for hardiness, with Busseron, Major, and Niblack next. In the more southern areas, of course, the more tender varieties are favored, such as Mahan, Success, Burchett, Schley and Stuart. Mahan seems to be the one most favored for general excellence in yield, flavor, and cracking qualities. It must be said, however, that, in flavor, these larger pecans are inferior to the best pecans of the indigenous northern varieties which are now being propagated. But because of their size, beauty, and productiveness, they will probably maintain their present leadership commercially.

Hybrid Pecans, Filberts, Butternuts. Reports from the south are inadequate for appraisal. The inference one must draw is that they are not being planted extensively there.

Persian Walnuts. The object of the inquiry, of course, was primarily to get information about varieties which might be capable of expanding their range toward the north. In this, so far as the southern reports are concerned, we have not been successful. Placentia and Eureka are mentioned in one report but their records, as reported, are not particularly good. Corroborative evidence is needed. Upon the whole, the south, strangely enough, seems not to be the place to look for Persian walnuts for the north. In California, the varieties of Persians, Juglans regia L., are well rooted to the ground. They object to more northern locations. This may not be entirely true of another species, J. hindsii, which in the past has shown a tendency to cross with other members of the juglans tribe. Crossed with the native black walnut, the hybrid known as "Royal" was developed, a robust grower which bears little. Crossed with the Persian, "Paradox" was produced. We are indebted to Mr. Harry S. Welby, of Taft, Calif., for some interesting J. hindsii varieties of good size and rather large, well filled kernel capacity. Upon their exterior, the nuts resemble the Persians, and the kernel has the Persian flavor. Inside the shell, the structure is that of the American black, with a substantial woody cross-brace, and the shell itself calls for a hammer for cracking. Neither Paradox nor Royal have proved of value except for stocks upon which the growers graft or bud their commercial cions. Much experimenting has been done in hybridizing J. hindsii, thus far without producing more than comparatively sterile "mules", but, the tendency to cross having been demonstrated, this work should be continued. Mr. Welby's samples have been sent to Mr. C. A. Reed, at the Beltsville Experiment Station, for evaluation. "Perhaps someone will know," says Mr. Welby, "the limit of cold J. hindsii will stand."

Mr. Welby's comments accompanying his report are too interesting to omit. He says: "On the grounds of an oilfield camp, I have carried on collaboration with the U. S. D. A. Bureau of Plant Introduction for twenty years. The importation of graftwood of eastern soft shell black walnuts has been "on my own." Of black walnuts we have bearing trees among ornamental plantings. There has been a marked change of attitude from the early days when I was more or less looked upon as a freak for working with them. The nuts are valued today. The original objective has been attained.

"In the meantime, I have purchased, 450 miles north of here, a twenty; have fenced and planted it to a brand of permanent pasture grasses known as "Evergreen", furnished by a grass specialist, Dale Butler, of Fresno. Prior to the grass, black walnuts, grafted and ungrafted had gone in. A strip bordering the highway was reserved for trees, we hope pistachio. There are now thirty of that variety, bearing, in an interior block.

"We have for years purchased black walnut meats in the Chico area. That would be a paradise for a black walnut man. And years ago I visited Teharna, a deserted village from the storybook, a former pony express station—wonderful black walnuts! Upon placing my camera upon a stump of a tree that grew in the street-parking, which had been logged, I braced the camera with a chip of this four-foot stump and discovered that the tree had been a curly walnut. The trees there are not J. hindsii, but Missouri blacks planted by forty-niners.

"Concerning pistachio: I doubt, considering the percentage of members who would be interested, whether I should bring this up, but there is need for just such an organization as the N. N. G. A. behind this tree. It does not lend itself to common nursery practice. It should be raised from seed, potted or in cans, reared without babying for several years, a horticulturist brought in, and your pistachio vera male and female blossoms worked to P. atlantica or chinensis. Lots of work but it is worth the trouble. It is deciduous with a hickory-like foliage; clusters of nuts clothed in pink-cheeked hulls. Bailey reports best nuts come from Sicily. Perhaps knowledge of them will be more widely disseminated when the boys return."

Hickories. This species seems not to be of great interest to the south. The old varieties are not mentioned in the reports. Nugget is mentioned by Mr. W. D. Dockery, of Steele, Ala., as one of the best. It grows well, yields well, its kernels have a good size and their quality is unusually good.

Of heartnuts, only one is mentioned, the Lancaster, which leaves much to be desired in performance in the south.

Suggestions and Requests. In response to the questions, "Is there any service that N. N. G. A. could render you not now being met?" and "Have you any suggestions for future work?", a number of responses were received which are worth noting.

Dr. O. D. Diller, State Exper. Sta., Wooster, O., "We are thinking in terms of another state wide nut contest in the fall of 1944." It will be remembered that the last Ohio contest brought the Brown and Tritton trees to light. Both are making friends by good production of good nuts. This is a suggestion for promotion in other states.

Sylvester Shessler, Genoa, O.: "Planted 10 nuts from Tritton parent tree in 1935. One seedling bore a larger nut than the parent tree. Several others bore very small nuts but all well filled."

J. Russell Smith, Swarthmore, Pa., "Urge the members to run local contests for good nuts. It may bring members if not nuts, and you may find some good new neighbors you didn't know about." (One easily worked plan is to see the secretary of your county fair board, offer to pay half or all prize money for best nuts from a single tree in your own and surrounding counties. See that judging is done by someone who knows how or do it yourself.)

Alfred J. Frueh, W. Cornwall, Conn., "Have had quite a lot of winter injury on the south-west side of black walnut trunks grafted near the ground. Note that seedling walnuts have a ridged, corky bark on the trunk already the second year, whereas a grafted trunk maintains its smooth bark for 6 to 8 years. Am now grafting on seedling stock 5 to 6 feet above the ground and much of the winter injury is thus eliminated."

A. B. Anthony, Sterling, Ill., "If they can be had disease free, promote the planting of a few of the most choice chestnuts in widely scattered regions where no one grows such trees. Possibly our children can get back to chestnut growing."

Seward Berhow, Huxley, Ia., "In a separate (pamphlet) or included in an early report, give a complete list of all named varieties, especially black walnuts, name of nut, name and address of originator, location of original tree, north latitude, year discovered, nuts per pound, score for cracking, kernel, prizes won. This would be very valuable for quick reference." The T. V. A. has issued a pamphlet giving much of this information. Also, we believe, Mr. C. A. Reed is at work on a book which will be worth waiting for.

J. U. Gellatly, Westbank, B. C.: "Could not the Association supply samples of recommended nuts or perhaps give lists of those who would sell small (3 or 4) nut samples. I have sent out such samples of 2 or 3 each of varieties I have on hand up to 9 or 12 kinds, at 50 cents per package, post paid. This is not enough to pay for the time consumed but is a good advertising practice."

Harry S. Welby, Taft, Calif.: "The ground squirrel is a pest here. Black walnut as bait will attract them in winter when fruits are scarce. At that time I have had some success with a box trap treadled by an electric contrivance instead of figure 4. Can anyone tell me any experience with scent baits which I believe Biological Survey trappers sometimes use? It may be a delicate question, but I should be interested in knowing more if the information is available."

R. T. Dunstan, Greensboro College, Greensboro, N. C.: "I would be happy if this survey brings to light information on the behavior of the best and more recently discovered hickories. (If not,) I believe an article on performance of such varieties as Whitney, Grainger, Bergor, Davis, Wilcox, Schinnerling, etc., perhaps similar to that by Reed in 1938 Proceedings, would be highly valuable and welcome. Perhaps a report on T. V. A.'s nut tree work in recent years would also be worth while."

C. H. Parks, Asheville, N. C.: "Would be interested in a chestnut that will grow in southern Appalachian regions." (See Mr. H. F. Stoke's report above. Chairman.)

Harold G. Williams, Ramsey, N. J.: "I believe that most useful trees, both fruit and nut, that are now commercially important, were developed from selected seedlings grown in the area in which they are being used. I have a suggestion. How about a concerted breeding program for nut trees with full membership participation? The best parent trees should be selected from present plantings of grafted, named varieties. Ship these seeds, or one or two year old seedlings from them, to each member on a subscription basis. Let each member make a trial planting of as many trees as he can. When these trees come into bearing there will be a better chance of finding superior strains that are adapted to their environment. Hybridizing by cross pollination requires more time and skill than many of our members possess. There are, however, members who now own orchards containing some of the best varieties, such, for instance (among the black walnuts) as Thomas, Stabler, Stambaugh, and perhaps Elmer Myers, planted in such close proximity as to allow for cross pollination. Seed could be purchased from them and resold to members for their planting; costs to be kept fairly low, with annual reports required as to care, cultivation, fertilizing and growth.

"An alternate plan would be to turn over such seed to Hershey, Smith, and other member nurserymen to plant, grow the young seedlings under best conditions, and furnish to member cooperators whose pledged subscriptions are to take care of the cost. This would give the cooperating nurseries a piece of business that could be depended upon (of a kind that would take comparatively little time as compared with that required for grafted trees), in return for their support. These trees could be planted fairly close, since most of them would prove to be useless as nut producers. If an outstanding variety is found, everything around it should be chopped down to give it room for development. I personally would raise and report upon some two dozen trees of this kind, and if a large group joined in the work, hundreds of tree could be tested."

Comment: That the chairman of this committee thinks the above suggestion a good one, and the project a good gamble, is evidenced by the fact that he has about a thousand of such trees now growing. Seed was bought from Mr. Harry Weber's, Rockport, Ind., and Mr. C. F. Hostetter's Bird-in-Hand, Pa., plantations in the fall of 1937 and planted at once. Most of the seed was from Thomas trees which had been flanked in the plantations with Stablers and other named trees, and from Stablers similarly flanked. The trees have now had six years' growth. He hopes for first nuts in 1944 from seedlings planted in deep loam only. Growth elsewhere has been negligible. If no outstanding nut producers are found, there will at least be some splendid timber, already assured.

It should be stated at once, however, that those whose object is the assured production of nuts, rather than the discovery or development of a new variety, should never plant anything but the best grafted trees bought from reliable nurserymen. Your decision should be governed by your interest. If you wish to be sure of nuts of a certain quality for home use, buy grafted trees of that quality. If, on the other hand, you have the urge to probe into the unknown and possibly create a new type, the above project will appeal to you, especially if you should lack training and time for more painstaking work. The following account is an example of the latter kind.

Arthur H. Graves, Curator, Brooklyn Botanic Garden, says: "We are breeding chestnuts for the purpose of obtaining a disease-resistant timber tree stock similar to the old chestnut tree which has now nearly disappeared on account of the blight. We started breeding chestnuts here at the Botanic Garden in 1930, and now after thirteen years of work, have on our plantation at Hamden, Conn., Litchfield, Conn., where the White Memorial Foundation is cooperating with us, and Redding Ridge, Conn., where Mr. Archer M. Huntington and the Connecticut Agr. Exp't Station are cooperating, about 1000 hybrids, a large number of combinations of Chinese, Japanese and American chestnuts, many of them now in the third generation from the beginning of the breeding period in 1930.

"We are carrying out our breeding program in the following way:

"We have selected the Chinese and Japanese species to cross with the American because the Asiatic species are disease-resistant, and we hope to incorporate this quality of disease-resistance with the tall timber growth of the American. We find that the Chinese are in general more disease-resistant than the Japanese. Other stocks which have been incorporated in our hybrids are the European C. sativa, the southern chinquapins C. pumilia, C. ozarkensis, C. floridana, and Dr. Van Fleet's old hybrid, presumably of C. crenata and C. pumila, which goes under the name of S8, and C. seguinii. After the hybrids become old enough, we inoculate the tallest of them with the blight fungus in order to get an index of their disease resistance. The most disease-resistant are bred together and of their offspring the tallest are selected, inoculated, and the most disease-resistant are bred together again. For example, this year we had 350 hybrids from last year's breeding experiments set out in a special nursery at Hamden and carefully tended during the season. Of these 350 we have selected 50 which are the tallest and straightest, that is, 20 inches and over. The others were sent to Washington, D. C., where the Division of Forest Pathology, Department of Agriculture, is working along a similar line, but with more attention to the nut phase of the problem.

"Our ultimate aim, of course, is to establish a race of chestnut trees which shall replace our now practically extinct American chestnut. The loss in money value from this timber tree has amounted to millions of dollars in comparison with which the value of its nut crops is very small indeed.

"However, we are interested in the nut problem, and whenever any particularly fine nuts appear we note the fact. We have now a strain of Chinese chestnut which has not yet come into bearing which we believe will have nuts as sweet as the old American chestnut, but much larger."

With this forward-looking note we close our report. We have a foundation upon which to build that is substantial and tried. The pioneering work of a patient, far-sighted, and distinguished group of workers has shown us much of what to do and what not to do. It is now up to us, the farmers, the planters, to multiply their work and continue it.

Side-lights on the 1943-4 Survey

Very many interesting bits of information have been included in the survey reports; so many that the committee has regretfully omitted some that hardly seemed properly to belong with the material of a survey, which after all must have some limits. One such item is from J. C. McDaniel, of Haines City, Fla., and has a special interest for members of this Association. He says:

"Perhaps you will be interested in data on one of America's largest Chinese chestnut trees, even if it does grow in Florida, at Monticello. It stands adjacent to a lot in which the late J. F. Jones had a nursery for a short time in the early years of this century, and apparently was planted at that time, around forty years ago. The trunk is now more than 25 inches in diameter below where it divides 6 feet above the ground. From this level, the tree branches profusely and has a symmetrical, rounded crown. It is healthy, not having a sign of the bark disease, although a native chinkapin 100 feet away is badly infested. It has abundant bloom and sets heavy crops of burrs but, lacking another variety for pollination, the number of nuts matured is small. Nuts are about average size for the species, of typical sweet flavor, and separate readily from the pellicle. Many of them become infested, before ripening, with a fungus which rots the kernel, apparently the same one which infests chestnuts and chinkapins at Savannah and Albany, Georgia. Mr. Paul Goldberg, of Monticello, the present owner, states that the tree has been bearing annually during the twenty years his family has owned it."

This nut-rot among the oriental chestnuts is one of the diseases that have become troublesome elsewhere. It is being studied and efforts are being made to combat it. Thus far, so far as we know, no effective cure has been found. A report upon present progress would be worth while.

Oscar E. Swan, Jr., Tulsa, Okla., reports an enviable situation. He says: "My nut trees are growing on a farm where more than 30 years of cultivation have failed to kill the native pecan sprouts. They come up year after year from the top roots. Since acquiring the place in 1936, I have allowed the pecan sprouts and the few native walnuts to grow unchecked except where necessary to cut them out to avoid crowding. The growth of these sprouts is quite vigorous, and they are ideal for top-working. I have top-worked a few trees every spring and now have about 300 grafted trees all the way from 6 to 30 feet tall. Many are too close together for full grown trees and I plan to thin them. My problems, so far, are the mechanical ones of top-working. I have settled upon a modification of the Biederman bark graft, which gives very good results. After the grafts are well established, the trees get very little attention except for cutting out the crowding trees. They are literally growing 'wild', yet the growth has been better than transplanted trees would have made with the best of care, because the root systems are well established in a situation which suits them.

"This system of neglect probably explains why I have failed with some species and varieties such as the butternut and some of the hickories. Occasionally I am pleasantly surprised, as in the case of some seedling Carpathian walnuts which, grafted upon some established black walnut sprouts, came through the severe 1943 drouth in fine shape without benefit of mulch, cultivation, fertilizer, or watering. The same applies to the Helmick hybrid. (A two year old tree, a hybrid walnut, grafted and growing well on black walnut stock, and which Mr. Swan says will bloom next year.) I have pampered my Chinese chestnut trees with cultivation, mulch and manure, as they are located in poorer, drier soil. They were badly hit by the drouth. Some died in spite of the attention.

"As to varieties, I am far enough south to grow all the standard southern pecan varieties, although several do not have a long enough season to mature their nuts. I am trying the northern varieties and, so far, am well pleased with their growth as compared with the southern kinds. It will be a few years before I can report on the size and quality of their nuts."

J. C. McDaniel again: "Source and variety of seed in Chinese chestnuts have a great influence on the performance of seedlings. Numerous seedlings from the original Hobson tree began fruiting in their second season of growth, and half of the ones I have are fruiting during their fourth season. On the other hand, I have a tree from imported seed which grew nine seasons before setting and ripening its first burr. The above data refer to my planting near Hartselle, Morgan County, Ala., and that vicinity. I have several black walnut trees under observation, native trees, on which data are not yet complete enough for evaluation."

If any man deserves a bright N. N. G. A. medal, it is A. L. Young, of Brooks, Alberta. Lowest temperature expected in winter, 45 deg. below; lowest known, 62 deg. below. Highest expected in summer, 101 deg.. Frequent drouths? Yes. Hot, dry winds? Yes. Native nuts found plentifully? None. Sparingly? None. Yet Mr. Young plants nut trees. It is men like that who have made Canada what it is. It takes more than mere weather to stop them. The never-say-die spirit of pioneers speaks throughout his report:

"Black walnuts, butternuts, some oaks, hazels and American chestnuts (Ohio buckeyes) all came through last winter well. However, late frosts reduced the nut crop. Of these species, filberts are not getting anywhere. Winkler, I believe, will eventually make a go of it. Heartnuts got a rough deal last winter, and European buckeye chestnuts were hurt a little by late spring frosts. Some Manchurian walnuts also got a setback with spring frosts, and some did not. Carpathian walnuts killed back quite a lot, so did most of my hybrid walnuts. Hybrid hazels seem perfectly hardy. Pecans, beechnuts and sweet chestnuts almost passed out of the picture last winter. Giant hickory from Ontario seems hardy but particular about the kind of soil and conditions. When irrigated, too much water will kill them. And this is true also of walnut and butternut seedlings. I have no acreage of nut trees. I grow seedlings and plant them wherever I find a place protected from the stock and within reach of moisture from the irrigation ditch, as this is a desert, cactus country.

"I always have a stock of seedling trees on hand, and whenever visitors show any interest, I give or send them fruit or nut trees and a few perennial flowers. So there are sure to be a few nut trees, some day, growing successfully throughout Alberta.

"There is more benefit from this northern seed, especially as I am using a commercial pollen with the hope of getting a hardy white walnut with possibly a coarse bark like the black to ward off sun-scald in this climate. They are on their way. I don't know when we'll be eating these imaginary nuts. However, it is not so long ago that fruit growing on the cattle range was a dream. I grew the first pears in Alberta, so far as we know. Now we are insulted if there is not a crop of fruit every year. I have many seedlings of standard apples, unnamed, that are really choice fruit, and, of course, a few named varieties that are doing fairly well. Minnesota has done great work in apple and plum breeding for the north. We are enjoying some of them right here.

"I am sorry that I have no data on husking, cracking, etc. Really even the hardiest, best trees bear nuts that, while of fair size, do not have fleshy kernels, and some have three sections instead of two. Butternuts are very sweet with fair size kernels. I was surprised, after a long hard winter, to find the Ginkgo trees still alive and gaining growth. Credit some or all this result to J. U. Gellatly and Paul Crath for supplying me with seed, seedlings, and pollen to carry on with. I am greatly obliged to them and also to George Corsan of Echo Valley, Islington, who has a wealth of nut interest.

"We have had a mighty dry year here, so, between irrigating and tending the largest herd of Ayrshire cattle in the prairie provinces, I have been busy. The town of Brooks is probably the only town in Canada on straight Ayrshire milk; and the change in Brooks from a box-car on a siding years ago to the Brooks of today, with its hundreds of healthy children now on the streets, is the marvel of a man's lifetime."

George H. Corsan, Echo Valley, Islington, Ont.: "Last winter, 1942-43, was by far the coldest ever recorded. No damage to filberts. A few inches of twigs were hurt on certain English walnuts. The Stranger heartnut, a tender variety, passed through unscathed. Persimmons and pawpaws passed without a bud killed. These are perfectly hardy varieties. Jujubes passed O. K., but that may be due to the very deep snows."

Dr. Oliver D. Diller, Associate Forester, Ohio Experiment Sta., Wooster, Ohio: "You will be glad to know that the experiment station has set aside some land for improved varieties of nut trees. If you find some promising walnuts which might be tested in this part of the state, we should be glad to have you keep us in mind." This is indeed welcome news and will be appreciated by all growers in this area.

J. G. Duis, Shattuc, Ill.: "A chicken yard is one of the best places to grow nut trees."

J. U. Gellatly: "I do not believe in selling nuts for seed purposes except on a very large scale."

J. C. McDaniel: "A neighbor lost some 5 year old Chinese chestnut trees following a summer drouth on silty loam soil, rather shallow to hard-pan. It is my observation that deeper, sandier soils (not too extremely sandy) are best for chestnuts in the coastal plain and other regions subject to summer drouths. In the mountains where summer rainfall is more uniform, they thrive also in clay soils."

G. H. Corsan: "Best success in grafting (hickories) has been in juicy, wet springs. Heartnuts must not be budded until late August (in Islington, Ontario). Heartnuts must not be pruned."

A. L. Young, Alberta: "There is a demand for young walnuts for pickling." (Does anyone know the details—when to pick, how to pickle?) (Note by Ed. Several recipes and methods in Am. Nut Journal now out of print but indexed by Ed. Copies of this index in his hands and those of Mr. C. A. Reed at Washington. Also recipes in 33rd Ann. Report p. 95).

Sterling A. Smith, Vermillon, O.: "With me, summer budding is the most successful means of propagating black walnuts."

J. Russell Smith: "Chinese chestnuts will blight some if under-nourished." Which includes the wrong kinds of soil, if uncorrected.

"Does anyone know for sure how to get pawpaw seed to germinate?" Several have asked this question. The chairman has had the same trouble, so can not answer. (Note by Ed. See "Nut Puttering in an Offyear" in this report.)

So far as the correspondence shows, no state or federal department buys seed on a large scale (with the exception, now, of chestnut seed) from trees of the better named varieties with which to grow seedlings for distribution by state nurseries for forest planting. All nut seed seems to be gathered haphazardly.

W. G. Tatum, Lebanon, Ky.: "A nut tree with plenty of root, top cut back one third, promptly set, roots protected, stem wrapped, 4 inches, mulch applied, set either spring or fall, grows for me 99% of the time. Failures are not worth mentioning if the above conditions are met."

Carl Weschcke, St. Paul, has a dozen or so extra hardy Persian walnuts by selection from some 12,000 seedlings. Also is introducing the hardy "Hazelbert," result of crosses between wild varieties and filberts.

"Dip wire screen guards in red lead and they will be good for twenty years."

Thomas and Stambaugh, among the black walnuts, are, with justice, entrenched leaders, but it will be well to watch Patterson, Mintle, Elmer Myers, Eureka, Creitz, Todd, and other promising new ones less well known. Thomas is more prolific in the south (generally) than in the north, which indicates that its bloom may possibly be out nearly enough to suffer in the north from late frosts.

Among chestnuts, the weight of evidence favors Hobson, Carr and Reliable, though J. Russell Smith says he has something he likes better than the first two.

Among pecans, Major, Greenriver, Pleas; among filberts and hazels, Winkler, Jones hybrid, Cosford, Gellatly, Brixnut; among Persian walnuts, Broadview, one or two Crath varieties, Payne, Breslau; among hickories, Stratford, Fairbanks, Barnes, Glover, Weschcke. These seem, so far as the returns show, to have outstanding points of superiority. In any such survey, injustice is bound to be done to some not fully reported.

Outside of filberts in the northwest, no northern grown nut can yet be said to have reached the status of a profitable commercial crop. (Exception: The narrow pecan belt along the southern terminus of the Ohio river valley; mostly wild trees.) Dr. A. S. Colby, University of Illinois says, "The report from the State Statistician at Springfield indicated a crop of 575,000 pounds of pecans for Illinois in 1943. I don't know just where they came from." Short crops were reported in Calhoun and Gallatin, leading nut producing counties. No reports have been received as to the size of pecan crops in the Kentucky and southern Indiana portions of the same belt.

The search for better varieties must continue, but it is also altogether likely that with an orchardist's attention, with cultivation, mulching, fertilizing, spraying one to three times yearly with Bordeaux and lead sprays, we might approach the commercial goal more closely with what we have today. Is anyone treating a bearing nut orchard as well as he would treat an apple orchard? That's the test.

S. H. Graham of Ithaca, N.Y. says: "The Ohio is commonly regarded as hard to hull. With a chained tire husker it hulls as well as any." He rates it for hardiness and a percentage of 90 to 100 for filled nuts, while Thomas yields only 0 to 90%.

Juglone—The Active Agent in Walnut Toxicity

By GEORGE A. GRIES, Connecticut Agricultural Experiment Station

The problem of walnut toxicity dates back at least to the writings of Pliny. In his "Natural History," this Roman philosopher stated that "the shadow of walnut trees is poison to all plants within its compass" and that it kills whatever it touches.

The first rebuttal to the existence of such a toxicity was forwarded by Evelyn in the 17th century. This author discussed the high regard in which walnuts were held in Burgundy as field trees. The roots of these trees were below the plow sole and thus did not affect either cultivation nor the growth, of grasses and cereals beneath them.

The pros and cons of the problem have been reviewed several times in the recent proceedings of the Northern Nut Growers Association. (Greene, 1930; MacDaniels and Muenscher, 1942; Brown, 1943.) That the roots of walnut trees are toxic to the roots of certain crop plants in direct contact with them is widely accepted. In nature this toxicity seems to be limited to plants with tap root systems such as tomato and alfalfa (Davis, 1923) and those with other types of deep root systems such as apple trees (Schneiderhan, 1927), rhododendrons (Pirone, 1938), and privet. This toxicity is exhibited only when there is a direct contact between the roots of the two plants involved. (Jones, 1903; Massey, 1925). That the wilting observed under walnuts is due to a toxic product from the bark of the walnut, and does not result from a lack of water, is substantiated by the fact that the vascular or water conducting system is discolored for several inches above the point of contact with the walnut root. This symptom is very similar to that produced by vascular disease fungi. No such discoloration results from wilting due to competition for water. This symptom of toxicity has been overlooked by many workers in the field.

Massey (1925) suggested that the toxic component of walnuts might be juglone. This idea was further supported by Davis (1928). Today this concept is widely held. Chemically this substance is known as 5, hydroxy-1, 4, naphtho-quinone and belongs to a group of strong oxidizing agents with commercial uses, including tanning agents, medicinals, poisons, etc.

A knowledge of the physiology of juglone in the walnut is essential to an understanding of the divergent results obtained by various experimenters. Juglone, as such, occurs probably only in minute quantities in the inner root bark, and in the green husks of the nuts. These regions are, however, rich in a substance known as hydrojuglone. This compound, the colorless, non-toxic, reduced form of juglone is immediately oxidized to its toxic form upon exposure to the air or some oxidizing substance from the roots of other plants. Upon standing in the air juglone again disappears, being either changed back to hydrojuglone or broken down into other non-toxic substances.

This sequence of events may be noted in a fresh green husk of a black walnut. When the fresh husk is cut, the interior is white but immediately turns yellow as the colorless hydrojuglone is transformed into the yellow juglone. Upon standing or drying the husk becomes black as further chemical changes occur. It is impossible to extract juglone from these dried husks without first reoxidizing them.

It now becomes possible for us to understand some of the discrepancies in the studies on walnut toxicity. If walnut bark or other plant parts are allowed to become desiccated, no toxicity may be found. If the roots of plants do not contact plant parts containing juglone or hydrojuglone, their oxidizing ability can not produce the toxin. Further the relative amounts of juglone in various species of Juglans has not been completely investigated. It does occur definitely in J. nigra and J. cinerea and has been reported as being in J. regia. Other species need investigation before being included as sources of juglone.

It is known that many plants are not adversely affected when grown under or near walnut trees. Some of these have root systems too shallow to contact the roots of the walnuts, especially in plowed ground. Some plants may send out sufficient surface roots to keep the plant alive in spite of injury to the deeper roots. The possibility that the roots of some plants are capable of withstanding the oxidizing power of the juglone is currently under study.

In early American folklore, the inner bark and the husks of the nuts were used as a source of a yellow dye for cloth. This yellow dye is juglone. The ancients also used this method of dying both cloth and hair.

Another property of juglone is its toxicity to fish. A few years ago it was a common practice in the South to cut the husks from young nuts and throw them immediately into a still pond of water. The fish, stunned by the juglone, would rise to the surface and were collected and eaten. No one seemed to worry about the effects of such poisoned food on the consumers.

Juglone is toxic to fungi and bacteria. Of all the medicinal powers attributed to walnuts by the Greeks and Romans, its use in curing certain skin diseases including ringworm has held up through the ages until many today can recall the use of the green husks for control of ringworms. Brissemoret and Michaud (1917) reported the use of juglone in clinical cases for the cure of eczema, psoriasis, impetigo and other skin diseases and concluded that juglone deserves extensive use in dermatology. To our knowledge the medical profession has not followed up the possibilities which this substance offers. The author is familiar with one case in which pure juglone was applied to a persistent ringworm infection. The infection disappeared within a month after treatment was begun. Though conclusions can not be drawn on a single case, certainly this observation lends credence to the medicinal lore of the ancients and the American pioneers.

During the fall and winter of 1942-43, investigations on juglone were started at the Connecticut Agricultural Experiment Station in conjunction with studies of the effect of other plant toxins on the roots of higher plants. When the toxicity of this oxidizing compound was established, it was produced in some quantity both by extraction from walnuts after the method of Combes (1907) and by synthesis after the method of Bernthsen and Semper (1887). Working on the assumption that the killing of germinating fungus spores and root hairs are similar phenomena, juglone was subjected to standardized laboratory tests for fungicidal value. In a series of experiments, this compound proved to be equally toxic with the copper in Bordeaux mixture. Such a high degree of toxicity was deemed worth further investigation, so juglone was tested as a seed protectant and as a spray in field trials for the control of black spot of roses.

As a seed protectant, juglone failed miserably. It's toxicity to the noncutinized surfaces of root tissues was so great that germination was abnormal and greatly impaired. The injury noted here was apparently the same as that discussed by Brown (1943) and that which occurs normally in the field.

In field tests on the control of black spot of roses juglone stood up well. No phytotoxic activity could be noted on the cutinized stem and leaf surfaces. On the variety George Ahrens, juglone gave equal control with 2-1/2 times as much 325 mesh sulfur, the standard control for this disease.


1. Under certain conditions walnut trees exhibit toxicity to those plants whose roots are in intimate contact with the roots of the walnut.

2. This toxicity is due to the action of juglone, the oxidized form of hydrojuglone, a non-toxic substance occurring in the inner bark and green husk of walnuts.

3. Juglone has been used in dermatology to cure various skin disorders including both bacterial and fungus diseases.

4. As a seed protectant, juglone is unsuitable because of its inherent toxicity to the non-cutinzed root surfaces.

5. Laboratory and field tests have shown juglone to be an excellent fungicide


1. Bernthsen, A. and A. Semper Ueber die Constitution des Juglons und seine Synthese aus Naphtalin. Ber. d. deutsch. Chem. Gesellsch. 20: 934-941. 1887.

2. Brissemoret et Michaud Sur une nouvelle classe de medicaments de la peau; les quinones peroxydes. Jour. pharm. et chim. 7e ser. 16:283-285. 1917.

3. Brown, Babette I. Injurious influence of bark of black walnut on seedlings of tomato and alfalfa. Northern Nut Growers' Assn., Proc. 1942:97-102. 1943,

4. Combes, R. Sur un procede de preparation et de purification des derives oxyanthraquinoniques et oxynapthoquinoniques en general, du juglon et de l'emodine en particulier. Bull. soc. chim. 4c ser. 1: 800-816. 1907.

5. Cook, Mel T. Wilting caused by walnut trees. Phytopathology 11:346. 1921.

6. Davis, Everett. The toxic principle of Juglans nigra as identified with synthetic juglone, and its toxic effects on tomato and alfalfa plants. Amer. Jour. Bot. 15: 620. 1928.

7. Greene, K.W. The toxic (?) effect of the black walnut: Northern Nut Growers' Assn., Proc. 1929: 152-156. 1930.

8. Jones, L. R. and W. J. Morse The shrubby cinquefoil as a weed. 16th Ann. Rpt, Vt, Agr. Expt. Sta. 188-190. 1902-03.

9. MacDaniels, L. H. and W. C. Muenscher Black walnut toxicity. Northern Nut Growers' Assn., Proc. 1940 172-179. 1941.

10. Massey, A. B. Antagonism of the walnuts (Juglans nigra I. and J. cinerea.) in certain plant associations. Phytopathology 15: 773-784. 1925.

11. Pirone, P. P. The detrimental effect of walnut to Rhododendrons and other ornamentals. Nursery Disease Notes 11; 1-4. 1938.

12. Plinius Secundus, C. The historie of the world. English translation by P. Holland, A. Islip, London. 1601.

13. Schneiderhan, F. J. The black walnut (Juglans nigra L.) as a cause of death to apple trees. Phytopathology 17: 529-540. 1927.

Possible Black Walnut Toxicity on Tomato and Cabbage


New York State Agricultural Experiment Station_

The toxicity or antagonism of black walnut roots and those of certain other plants has been a controversial question. L. H. MacDaniels and W. C. Muenscher in a report on page 172 of the Thirty-first Annual Meeting of the Nut Growers' Association held in 1940 cited evidence pro and con relative to the toxic effect of black walnut on various crops. They concluded that because of conflicting evidence, the problem of walnut toxicity was still unsolved and needed further investigation. In 1942, Babette I. Brown reported on page 97 of the Thirty-third Annual Report of the Northern Nut Growers' Association, on the injurious influence of bark of black walnut roots on seedlings of tomato and alfalfa. It was concluded, from carefully conducted tests, that walnut roots produce a substance that may be injurious to certain other plants. Experimentation showed that the walnut root bark produces a substance that is injurious to alfalfa and tomato seedlings.

During the past years, a number of instances of stunting and wilting of tomato plants in the vicinity of black walnut trees has been observed. In 1942, a very definite case of wilting and stunting was noted in cabbage plants growing in the vicinity of a black walnut tree.

Severely wilted tomato plants were observed on July 30, 1943, in a field of tomatoes near Egypt, New York. This case was typical of others observed in tomato fields in recent years. The wilting and stunting were all located in one corner of the field, on both sides of which large black walnut trees were growing, and extended out in the field for a distance somewhat greater than the height of the trees. The rest of the field planted with the same stock of tomatoes was entirely healthy. The field had been planted to beans in 1942 and prior to that had been in grass for at least 7 years. The vascular bundles of affected plants were browned as in Verticillium or Fusarium wilt and in some bacterial diseases. No cankers or discolorations were observed on the external parts of the plants. In order to determine whether or not the wilting was caused by a fungus or bacterium, plants were collected for microscopic examination and for culturing to show possible presence of pathogens. The microscopic examinations showed the absence of fungi or bacteria in the vascular system or other plant tissues. The browning in the vascular bundles appeared to be confined to the phloem tissue. All attempts to culture a pathogenic fungus or bacterium from affected tissue was negative. Portions of diseased plants with discolored vascular bundles were placed in a damp chamber and no fungus or bacterial growth developed from the vascular system. From these field and laboratory studies, it was concluded that the wilting and stunting were not produced by a plant pathogen. Since the affected plants in the field were all confined to the area adjacent to black walnut trees, and the fact that it had been shown that the bark of this tree does produce a substance that is toxic to certain plants, it was concluded by circumstantial evidence alone that the wilting possibly was due to black walnut toxicity or antagonism of some sort.

In August of 1942, studies were made on wilted and stunted cabbage plants growing in a semicircle on one side of a field adjacent to a walnut tree (Fig. 1). The field was located near Hall, New York, in a region known to be infested with cabbage yellows. From a distance, the affected plants appeared to have yellows, but upon close study, it was found that they were merely wilted and stunted and did not show the other typical symptoms of the yellows disease. The root systems of wilted plants did not show the presence of club root or black rot infection. The plants in the field were all of one variety and came from the same seed bed. Microscopic studies and attempts to culture a fungus from the vascular bundles of affected plants showed the absence of any fungus that might have caused, the disease. Since the affected plants showed no symptoms of known cabbage diseases and as they were growing in a semicircle adjacent to a walnut tree, it was concluded that the presence of the root system of this tree might have been the cause of the trouble.

These two instances of wilting and stunting of plants in the vicinity of walnut trees give further circumstantial evidence that the trouble might have been caused by the toxicity or antagonism of black walnut roots. Detailed experiments with the plants in question would have to be run to prove this assumption.

Preliminary Studies on Catkin Forcing and Pollen Storage of Corylus and Juglans

L. G. COX, Cornell University

Methods of collecting and storing pollen are of great interest to those engaged in plant breeding. Very little reliable information is available for the various nut species compared with many other horticultural plants. The following preliminary experiments were conducted to obtain data on germination media, forcing methods, and storage conditions for Corylus and Juglans Sieboldiana pollen. The former was mostly from hybrid plants produced by crossing the Rush filbert (Corylus americana) with European varieties.

The optimum temperature and sugar concentration for germination of Corylus pollen.

The cut ends of Corylus branches with mature catkins collected March 1, 1942 were immersed in water and forced into shedding pollen in a room at a temperature of approximately 20 deg. centigrade. The collected pollen was sifted upon the surface of a thin layer of sugar-agar in petri dishes.

Commercial cane sugar was used in preference to purified sucrose, because other studies have shown it to contain impurities which stimulate pollen germination. A range in sugar concentration from 5% to 55% by weight in 5% intervals was made up in distilled water containing 1.5% agar, heated to boiling and poured into the petri dishes.

The pollen was incubated at 10 deg. C. and at 25 deg. C. on the agar medium for 48 and 24 hours respectively prior to making the germination counts. Pollen was assumed to have germinated if the length of the pollen tube exceeded the diameter of the pollen grain.

At 25 deg. C. germination was prompt and uniform with a maximum of 19.5% at 25% sugar concentration. At 10 deg. C. the rate of germination was very slow and incomplete at the end of 48 hours with a maximum of 9% germination at 35% sugar concentration. For subsequent work a temperature of 25 deg. C. and a sugar concentration of 25% by weight was taken as a standard.

The effect of temperature and humidity during forcing on the viability of the pollen

Pollen shed from catkins forced in a warm, dry room (about 75 deg. F.), and in a cool, humid greenhouse (60 deg. F.) gave pollen germinating 36% and 69% respectively, which indicated that the air temperature and humidity surrounding the developing catkins may have considerable effect on the viability of the maturing pollen.

The experiment was repeated by forcing the catkins at 10 deg. C., 18-20 deg. C., and 24-26 deg. C., at two humidity levels. The low humidity level corresponded to the natural room humidity, about 25% and the higher level of nearly 100% was achieved by enclosing the branches with catkins in large sealed cans over a water surface. As soon as a majority of the catkins began to shed their pollen or to absciss their full developed anthers, the catkins were removed and dried on a sheet of smooth paper at room temperature until the pollen was shed. The pollen was then collected and stored at 4 deg. C. until used. The results obtained are given in table 1.

Table 1. Percentage germination after 24 hours of Filbert pollen forced at different temperatures and humidities.

——————————————————————————————— Temperature

10 deg. C. 18-20 deg. C. 24-26 deg. C.

Low humidity 80 31 7

High humidity 96 60 12 ———————————————————————————————

Later experiments indicate that the pollen viability is greatly lowered if the catkins are removed from the higher humidities prior to the maturity of the anthers as indicated by their tendency to shed their pollen. Apparently the high humidity hinders the dehiscence of anthers and shedding of the pollen grains.

Effect of catkins extracts on pollen germination

The failure of pollen to germinate in the catkins at 100% humidity suggested the possibility that the catkin tissue might contain some substance which prevented germination of the mature pollen grains until after it was shed.

Two mature catkins plus remnants of their unshed pollen were ground in a mortar with a small amount of water in clear quartz sand. One cubic centimeter of the resulting turbid suspension was added to 10 cc. of warm fluid agar and mixed by rotating the petri dish.

Pollen which gave a 91% germination on the standard medium showed only 50% germination on this catkin extract. Germination was distinctly abnormal with short stubby pollen tubes, often with numerous nodular swellings. In general the pollen tube grew up into the air away from the surface of the agar, rather than down into it or parallel with the surface as in normal germination.

Storage of Corylus and Juglans Sieboldiana pollen

Sulphuric acid solutions to give humidities from 10% to 100% in 10% intervals were made up. The storage chambers consisted of Atlas one-pint, wide-mouth fruit jars. In the bottom of each was placed a small 1-oz. bottle containing 20 cc. of the sulphuric acid solution. The pollen was placed in small glass vials loosely stoppered with cotton.

Two lots of Corylus pollen of 80-1/2 and 96-1/2 initial viability respectively, and one lot of Juglans Sieboldiana pollen of well over 50% viability were used in the experiment. Storage temperatures of 0 deg. 40 deg. and 10 deg. were used.

The Corylus pollen was placed in storage March 20, 1942, and the Juglans April 12, 1942. The pollen was taken out of storage November 28, 1942 and germinated on the standard agar-sugar medium at 25 deg. C. for 24 hours. Results are given in table II.

Table II. The effect of storage temperature and humidity on percentage germination of Corylus and Juglans pollen

————————————————————————————————— Kind of Temperature Degrees Per cent relative humidity Pollen Centigrade 10 20 30 40 50 60 70 80 ————————————————————————————————— Corylus 10 deg. 0 0 0 0 0 0 0 — Juglans — 0 — 0 3 0 0 — Corylus 4 deg. 0 0 0 0 9.0 0 — 0 Juglans — 0 — 0 — 0 0 0 Corylus 0 deg. 3.0 1.0 4.5 8.5 0 0 0 0 Juglans — 0 — 12.0 — 12.0 0 0 —————————————————————————————————

This preliminary work indicates that Corylus pollen can best be stored at 0 deg. C. at 30 to 40% relative humidity and Juglans pollen at 0 deg. C. at 40 to 60% relative humidity.


1. The optimum sugar concentration for germination of Corylus pollen is around 25% by weight in 1.5 per cent agar at 25 deg. C.

2. Forcing the catkins at a low temperature (4 deg. C.) and at high relative humidity (80%) favors the development of a high percentage of viable pollen.

3. The catkins contain some substance which when added to the germination media inhibits pollen germination and causes abnormal types of germination.

4. Preliminary results on pollen storage indicate that Corylus americana pollen can be stored for eight months or more in a viable condition at 0 deg. C. with a range of 30 to 40% relative humidity. Juglans Sieboldiana pollen can be stored at 0 deg. C. at 40 to 60% relative humidity. Whether or not pollen stored for this length of time would be effective in plant breeding should be tested by actual trial. The supposition based upon studies with other pollens is that germination tests are a reliable indication of the effectiveness of pollen in fertilization.

Storage and Germination of Nuts of Several Species of Juglans


Cornell University, Ithaca, N.Y.

While working on the general problem of the possible toxic effect of the roots of species of Walnut (Juglans) upon other plants we have had occasion to germinate the nuts to produce seedlings for experimental use.[1] The storage treatment employed previous to planting the nuts provided a successful method of supplying viable nuts. The simple treatment used, a modification of that suggested by Barton,(2) is briefly described and the results that may be obtained are indicated in a report of some germination data from the plantings of 1943.

The nuts were harvested after they had fallen from the trees and were stored in a cool place as soon as possible thereafter until the time when the husks were removed. Those harvested at Ithaca were put in cold storage at once; those harvested in California or Texas were delayed a few weeks during shipment. The husked nuts were stratified between layers of moist peat 2 cm. thick in two-or five-gallon crocks. The uppermost layer of nuts was covered with peat to a depth of about 10 cm. The nuts were placed in a cold room at 1 to 3 deg. C. in late autumn and left until they were planted, between April 15 and June 2. Nearly all species used germinated well after about five to six months of cold storage.

Table 1 shows the results obtained from treated nuts of ten species of Juglans when they were planted in the open field, in soil in the greenhouse or in moist sphagnum in the greenhouse. While some variation in germination is observed, most of the species gave a good germination under all treatments. The field planted seeds were somewhat slower in appearing above the soil surface than those planted in the greenhouse. This delay may have been caused by the cold rainy weather soon after planting. The firmness of the soil, a clay loam, may also have retarded the emergence of the seedlings.

The germination percentages are based upon lots of 100 nuts except in a few species in which only 50 nuts were used. Differences in the percentage of germination obtained from various plantings of the same species are slight in most species. Even the larger differences in germination obtained in a few species cannot be considered significant but probably indicate variations in the quality of the original lots used.


Walnuts husked soon after harvest, before they are completely air-dried, and stored in moist peat at 1 to 3 deg. C. for five to six months have their dormancy broken and remain viable for at least three months thereafter. This treatment is effective for all ten species tested. It is probably effective for all species of Juglans. This method of handling the nuts has the advantage over outdoor stratifying or autumn planting which often result in much damage or loss of nuts from the activities of rodents.

Table 1. Germination of nuts of Juglans spp. after stratifying in peat over winter, at 1-3 deg.C.

Per cent germination - Date Planted in Planted Kind Source entered soil in Planted in in greenhouse in field sphagnum storage April 15 April 24 June 2 - - nigra (Cornell) Ithaca, N.Y. Oct. 1 70 80 68 nigra (Cayuga) Ithaca, N.Y. Oct. 1 100 80 cinerea Ithaca, N.Y. Oct. 1 60 44 8 regia (Sorrentina) Chico, Calif. Nov. 9 66 48 8 regia (Franquette) Chico, Calif. Nov. 9 80 36 regia Chico, Calif. Nov. 9 75 46 Sieboldiana Ithaca, N.Y. Oct. 1 100 40 honorei Chico, Calif. Dec. 18 60 55 46 pyriformis Riverside, Calif. Nov. 9 10 54 31 rupestris Alpine, Texas Oct. 1 40 83 50 major Riverside, Calif. Nov. 9 90 92 66 californica Pomona, Calif. Nov. 9 62 84 91 californica quercina Chico, Calif. Dec. 18 18 25 hindsii Riverside, Calif. Nov. 9 50 56 52


1. Brown, Babette I. Injurious Influence of Bark of Black Walnut Roots on Seedlings of Tomato and Alfalfa. Northern Nut Growers Association, 1942: 97-101. 1943.

2. Barton, Lela V. Seedling Production in Carya ovata. Juglans cinerea and Juglans nigra. Contr. Boyce Thompson Inst. 8: (1) 1-5. 1936

A Key to Some Seedlings of Walnuts


Cornell University, Ithaca, N.Y.

While working with the seedlings of several species of walnuts certain diagnostic characters, by which the common species can be separated, became evident. These characters have been used to make a key to seedlings from one to three months of age. This key has been found helpful to us and it is here presented in the hope that it may prove useful to others who need to handle and determine walnuts in the seedling stage.

The key has two main divisions based upon the types of leaves on the main axis. The first division includes three species, Juglans sieboldiana, Japanese butternut, J. cinerea, American butternut, and J. regia, Persian or English walnut, all of which have only compound green leaves. In addition, one or more pairs of minute simple scales or buds occur on the lower part of the stem but above the cotyledons. The second main division includes species in which the seedlings have several simple, alternate, scale-like leaves followed successively by serrate, lobed and finally compound leaves forming a gradual series. This group includes Juglans rupestris, Texas black walnut, J. nigra, eastern black walnut, J. honorei, Ecuador walnut, J. pyriformis, Mexican walnut, J. major, Arizona black walnut, J. californica, California black walnut, and J. hindsii, Hind's black walnut.

It is important that the leaves on the primary axis arising from the plumule are examined. If the primary axis is injured secondary shoots may arise from the axils of the cotyledons. These may develop various types of leaves not necessarily like those of the primary axis. The key is based upon seedlings grown in the field and in the greenhouse at Ithaca, New York.

A Key to seedlings of some species of Juglans

1. Leaves on the primary axis all compound; 1 to 4 pairs of opposite or subopposite reduced scales or buds sometimes present on the lower axis but above the cotyledons.

2. Scales or buds wanting between the lowest compound leaves and the leaves and the cotyledons J. sieboldiana

2. Scales or buds in pairs on 1 to 4 nodes below the compound leaves.

3. Stem with 1 pair of opposite scales or buds near the base; leaflets hairy, serrate J. cinerea

3. Stem with 2 to 4 pairs of opposite scales or buds below the compound leaves; leaflets glabrous, entire or denticulate J. regia

1. Leaves on the primary axis alternate, forming a gradual series from simple, entire scales to compound leaves; the lower 3 to 8 leaves simple.

4. Lateral veins of leaflets all or mostly all terminating in the notches between marginal teeth J. rupestris

4. Lateral veins of leaflets or their main branches all or mostly all terminating in the apex of marginal teeth.

5. Midrib of leaflets glandular hairy.

6. Glandular hairs on midrib of young leaflets interspersed with stellate clusters of gray glandless hairs; lateral leaflets ovate to broadly lanceolate, rugose J. nigra

6. Glandular hairs on midrib of young leaflets interspersed with sessile, usually yellow glands; lateral leaflets lanceolate, not rugose J. honorei

5. Midrib of leaflets glabrous or nearly so, sometimes with scattered, sessile glands.

7. Leaflets lanceolate, with acuminate apex; rhachis glabrous.

8. Leaflets widest near middle; vein-islets prominently raised; free ends of veins wanting or if present distinct to the apex and mostly unbranched J. pyriformis

8. Leaflets mostly widest below the middle; vein-islets not prominently raised; free ends of veins slender, terminating in indistinct branches J. major

7. Leaflets ovate or nearly so, with obtuse or acute apex; rhachis somewhat pubescent.

9. Petioles of the 3 lower compound leaves less than 1 cm. long; leaves crowded on a short axis J. californica

9. Petioles of the lower compound leaves from 1+ to 3 cm. long; leaves more distant on an elongated axis J. hindsii

Further Tests with Black Walnut Varieties

L. H. MACDANIELS and J. E. WILDE, Cornell University

In 1937 the Northern Nut Growers Association committee on varieties and judging standards proposed a tentative schedule for the judging and evaluation of black walnut varieties(1). It was pointed out at that time that for one reason or another none of the schedules which had been used in judging walnuts were satisfactory and usable in giving an accurate estimate of the cracking quality and value of a variety. It was recognized also that the schedule proposed was only tentative and that it would need to be modified in the light of future testing and experience. In 1939 the question was again considered(2) and on the basis of tests which had been made, changes were proposed which would make the schedule more realistic. Since then many tests have been made using the modified schedule. The purpose of this paper[A] is to give the data secured in these tests and to consider again the value of the schedule and possibilities of improvement.

[Footnote A: The authors are indebted to many persons for furnishing samples for testing and for making duplicate tests. This cooperation is gratefully acknowledged with thanks.]

Recently a number of papers have been published dealing with the evaluation of black walnut varieties. In 1941 Kline and Chase(3) compiled the available published data and additional tests made by the Tennessee Valley Authority on nut weight and kernel percentage of black walnut selections. Two hundred and twelve clones and 335 tests are reported. As would be expected the samples of the same variety from different localities show variation in weight per nut and in total per cent kernel. For example, in 12 samples of the variety Ohio the weight per nut varies from 14.8 grams to 18.7 and the per cent kernel from 16.6 to 32.9. Twenty-one tests of Thomas show variations in single nut weight from 16.7 to 25.0 grams and in per cent kernel from 19.0 to 30.0. In general the samples grown in the north were made up of smaller nuts with less per cent kernel, indicating that the varieties were not suited to that latitude.

In 1942 Kline(4) worked out a somewhat technical method of evaluating walnut varieties on the basis of cash return per hour of labor spent in cracking with a hand operated cracker. A formula is proposed in which the variables of price and other factors may be substituted. The approach is on a commercial basis and the method is not intended for use in evaluating small samples. The paper represents many tests and establishes or affirms by statistically treated data several points of general interest in walnut testing, namely, (1) that a 25 nut sample is large enough to show varietal or other differences of a gram in total weight or 1 per cent of kernel weight, (2) that unless extreme accuracy is desired, moisture content may be ignored in making tests of 25 nut samples if the nuts have been hulled and air dried for about two months and (3) that the mean weight per nut and per cent kernel of nuts from the same tree may vary appreciably from year to year, for example a variation of 4.9 grams per nut and 3.3 per cent in kernel weight is reported for Snyder. Such variation is recognized and emphasizes the necessity of testing a variety in any locality for a number of years if correct valuation is to be made.

In Kline's paper earnings per hour for fifteen black walnut selections are given showing a maximum of $0.279 for the variety Norris, $0.245 for Ohio down to $0.12 for an unnamed seedling.

Lounsberry(5) published kernel cavity measurements for 64 clonal selections and related these to kernel weight per nut. Measurements of the thickness of the partition separating the halves of the kernel are also given. He does not relate these characters to scoring or cracking quality.

The purpose of the scoring system under discussion in this paper is to provide a realistic method of judging the relative merit of different clones of black walnuts that can be used mostly by members of the Northern Nut Growers Association or others having some skill in cracking technique. At the present time the Association has little reliable information either as to the performance of different varieties under different conditions in any one locality, from year to year on the same tree, or the suitability of any one variety growing in far different parts of the United States. It is important that such information be available and a workable basis of evaluation would be of the greatest value in obtaining it. Much of our information at the present time is from the many tests made by N. F. Drake(6, 7, 8) which are of great value in rating varieties. His schedule is an improvement over any previously proposed but fails to provide standard sampling and cracking procedure and includes the items of flavor and color which are in no way objective characters. The use of a point score based on the concept of a "perfect nut" is cumbersome and considered undesirable by the committee.

It is recognized that the value of a variety depends also upon the bearing habit of the tree, the nature of the husk, disease resistance and other characters.

It has been five years since the present schedule was proposed and enough tests have been made to give a basis for judgment as to the merits and weaknesses of the schedule. As stated in the original committee report it is generally agreed that the best measure of the value of a nut of any clone is the amount of usable or marketable kernels that can be obtained from a given weight of shucked nuts with the least labor. The characteristics of the nuts that contribute to this value are recognized as follows:

1. The size of the individual nut.

2. The per cent of kernel of total sample weight recovered without recracking and without the use of a pick.

3. The total per cent of kernel of total weight of sample.

4. The number of quarters.

5. The plumpness of the kernels.

6. The number of empty nuts or nuts with shrivelled kernels in the sample.

Flavor and color may be important but are so dependent upon personal preference and on the treatment of the samples before testing that they cannot be rated numerically.

In considering the value of any schedule the following questions are pertinent:

1. Is it possible for one operator testing one lot of nuts to obtain the same score with replicate random samples?

2. Is it possible for different operators to obtain approximately the same score on replicate samples?

3. Does the score give an accurate evaluation of the variation of a variety from year to year in one locality or in the same year in different localities? The latter is very important in determining the regions to which the variety is best adapted and the performance of the variety in any one locality.

4. What are the causes of variation in the scores obtained? Which of these reflect the inherent worth of the sample and which are related to technique, personal equation and methods of handling the sample?

5. What changes may be made in the schedule to weight the various factors to give a more realistic score of what changes in procedure will make the schedule more realistic?

Table 1 gives data on replicate samples tested by the same operator. In the samples of Spear, numbers 1-6 the variation is as follows: weight of single nut 1.3 grams, per cent kernel first crack 2.9, total per cent kernel 2.6, number of quarters 3, penalties 4.5 points, score 9.2 points. In scores figured without penalty the variation is 5.4 points. Sample No. 7 was cracked November 4 before the nuts were dry and hence is not comparable with others.

Analysis of these differences indicates that the variation in nut weight is closely related to the number of shrunken and empty nuts in the sample. This is a difficult factor to evaluate in a practical way. At the time of the 1939 report it was suggested that the score should be figured on the basis of filled nuts. This cannot be arranged easily in testing because if the operator cracks the nuts before weighing there is almost sure to be loss of fragments of shell. Trying to correct the original weight in any way is necessarily inaccurate. Deciding whether or not the kernel of a nut is sufficiently shrivelled to deserve a penalty is a matter of judgment which is a personal matter.

The variation in per cent kernel first crack and total per cent kernel probably represents fairly the difference in the samples. The total per cent is a wholly objective value and varies practically as much as the per cent first crack. Uniformity in the number of quarters is striking. This large number is undoubtedly related to the fact that many of the kernels were shrunken enough to be penalized and others were perhaps shrunken enough so that they did not tightly fill the shell cavity. In general it may be said that the more tightly the kernels fill the shell the more difficult it is to extract large pieces. Thus having the kernels a little shrunken but not enough to seriously reduce their weight favors a higher score. Of course, in some varieties the kernels may he plump and still not fill the shell tight enough to make cracking difficult. This is a desirable condition.

Variability in penalties is more important (i. e. 4.5 points) than any other factor in influencing the final score. Without the penalties the scores of samples 1 to 6 would be 87.5, 84.0, 83.6, 83.7, 82.1 and 82.8 respectively which is fairly uniform. Statistically the presence of empty or shrivelled nuts in a lot from which samples are taken increases the number required to make a satisfactory sample by greatly increasing the individual variation of the single nut.


Variation in the score of tests of duplicate samples made by the same operators. Twenty-five nut samples. Nuts grown at Ithaca, N.Y.

1942. Black Walnuts.

KEY: A: Wt. 1 nut grams B: % kernel 1st crack C: % kernel total D: Quarters number E: Penalty F: Score

——————————————————————————————————————- Variety Treatment A B C D E F Remarks ——————————————————————————————————————- Spear No. 1 S 18 hours 14.6 24.9 28.0 91 -3.5 84.0 1 empty, 5 shr. D 15 hours Spear No. 2 D 15 hours 15.7 24.0 26.8 94 -6.1 77.9 3 empty, 6 shr. Spear No. 3 D 15 hours 15.9 22.9 25.4 92 -3.5 80.1 1 empty, 5 shr. Spear No. 4 Dry 15.0 23.3 25.4 94 -5.0 78.7 1 empty, 8 shr. Spear No. 5 Dry 15.4 22.0 26.8 93 -4.5 77.6 1 empty, 7 shr., 20 bnd. qtrs. Spear No. 6 Dry 14.7 22.7 26.6 94 -8.0 74.8 4 empty, 8 shr., 16 bnd. qtrs. Spear No. 7 Nov. 4 16.7 27.9 28.8 98 96.7 only partly dried, 16 halves Snyder No. 1 Dry 16.8 23.1 26.0 87 -4.0 80.7 8 shr., 9 bnd. qtrs. Snyder No. 2 Dry 16.0 24.0 26.3 74 -3.5 81.0 1 empty, 5 shr., 13 bnd. qtrs. Snyder No. 3 Soaked 15.8 24.1 25.8 86 -4.0 77.5 1 empty, 6 shr., 8 bnd. qtrs. Snyder No. 4 Soaked 16.2 23.1 25.6 78 -7.5 75.5 3 empty, 9 shr., 8 bnd. qtrs. Snyder No. 5 Dry 18.2 19.9 26.4 90 -3.5 76.7 7 shr., bnd. Snyder No. 6 Nov. 4 21.2 27.6 29.8 95 100.8 qtrs. Eldridge Dry 20.8 19.3 23.1 98 80.7 13 halves, not Geneva, N.Y. well dried out " Dry 20.6 20.0 22.6 92 81.0 ——————————————————————————————————————-

With the variety Snyder a difference of 2.4 grams in weight per nut in samples 1 to 5 suggests poor sampling technique as this is an objective value. A difference of 4.2 per cent in first crack suggests carelessness on the part of the operator in cracking or difference in soaking as this is quite out of line with the variation of .8 per cent in per cent weight of total kernel. The difference of 16 quarters is considerable but represents only 1.6 score points. As with the Spear the variation in penalty of 4 points is greater than other factors except per cent first crack (i.e. 4.2% points). The difference in score of 5.5 points is obviously greater than desirable, but probably indicates the relative value of the samples. Without penalties the difference is 4.5 points.

Sample 7 of Spear and number 6 of Snyder were cracked November 4th when only partly cured and show the importance of curing in obtaining an accurate rating for a sample. The score of each variety was increased materially in all characteristics and no shrivelling was apparent. As a practical means of recovering the kernels in large pieces, cracking before the nuts are dried out is a decided advantage provided the kernels are cured before they are stored.

The duplicate samples of Eldridge check very closely and show no significant differences.

In Table 2 are given the results of ten tests on carefully replicated random samples of Snyder black walnuts. In making these samples the nuts were spread in a single layer on the floor and lots of 25 cut off the edges of this layer without selection of any kind. Even with such selection there is a variation of 1.2 grams in the average weight of single nuts from different samples. Per cent kernel first crack shows a minimum of 21.8 and a maximum of 26.9 in the ten samples. This difference is related mostly to the presence of 3 empty nuts in the low scoring sample as compared with none in the high scoring sample. The high score is also in part due to soaking. This variability is about the same as with total per cent kernel indicating that cracking technique was uniform. Comparing samples 1 and 2 in more detail it is found that the difference of 11.6 points in the score is caused by the presence of empty nuts in the sample. The average weight of kernels per single nut in sample 1 is 4.9 grams. The difference in the weights of the kernels of the two samples is 15 grams or about the weight of the kernels of 3 nuts. These empties also reduce the score by reducing the number of quarters recovered. Where empty nuts are involved, it is doubtful if random sampling will reduce variation unless the size of the sample is greatly increased, a practice which is not a practical solution in that a 25 nut sample is about as large as can be handled with any facility. It would seem that this difference in scores was a fair indication of the merit of the two samples. The scores of the other samples show a fair degree of uniformity. The high score of sample 4 is probably related to the soaking treatment though the scores of sample 3 also soaked is lower than that of sample 6 which was not soaked. It seems that when these conditions and with this variety stored in a fairly high humidity, soaking had little effect except to increase the number of halves recovered.


Cracking tests by single operator with 10 random replicate samples of Snyder black walnuts. 1942 crop. 25 nut samples.

KEY: A: Wt. 1 nut grams B: % kernel 1st crack C: % kernel total D: Quarters number E: Penalty F: Score

Sample Treatment A B C D E F Remarks ——————————————————————————————————————- 1 Dry as received 18.1 21.8 23.1 85 -9.0 72.7 3 empty, 12 shr. 2 Dry as received 18.5 24.0 25.8 99 -5.0 84.3 10 shr. 3 Soaked 9 hrs., dried 14 hrs. 18.6 25.7 28.0 94 -6.0 87.4 1 empty, 10 shr., 8 bnd. qtrs., 16 hvs. 4 Soaked as above 18.3 26.9 28.4 99 -4.5 91.7 9 shr., 5 bnd. qtrs., 19 hvs. 5 Held in cellar 4 days 18.0 24.4 25.7 90 -6.5 82.1 1 empty, 11 shr., (high humidity) 8 bnd. qtrs. 6 Held in cellar 7 days 19.0 25.6 27.2 99 -5.0 88.7 10 shr., 7 bnd. qtrs., 3 hvs. 7 Held in cellar 7 days 18.4 23.9 26.1 96 -6.5 82.3 1 empty, 11 shr., 9 bnd. qtrs. 8 Held in cellar 4 days 19.2 24.8 26.6 98 -5.5 86.4 11 shr., 4 bnd. qtrs. 9 Held in cellar 4 days 18.4 23.7 26.7 92 -7.5 81.6 2 black counted as empty, 11 shr., 12 bnd. qtrs. 10 Held in cellar 4 days 18.6 23.5 25.9 94 -5.5 83.4 1 empty, 9 shr., 10 bnd. qtrs. ——————————————————————————————————————-

Another lot of 24 random replicate 25 nut samples of Ohio black walnut from the original tree was made by scooping the nuts out of a bag with a quart berry box which held about 25 nuts. Care was used not to select the samples in any way. The lightest sample 3 weighed 385 grams, the heaviest 22 weighed 434 grams or a difference of 2 grams per nut. The score of these two samples was 85.0 and 85.4 respectively apparently because there were no empty nuts in either sample.

The results of tests on 18 of these replicate samples of Ohio are given in Table 3. The nuts were apparently a uniform lot. The kernels while of good quality were in most cases not quite plump and did not fill the cavities of the shell tightly. This doubtless accounts for the large number of quarters recovered. The kernels on the whole were plumper than with the variety Snyder reported in Table 2 and there were fewer empty nuts. Of the samples that were not soaked the variation of 4.3 per cent in the per cent first crack is of the same order as variation of 3.6 per cent for total per cent kernel and indicates uniform cracking technique.

The data in Table 3 gives evidence of the effect of treatments before cracking. The first nine samples marked with an asterisk were held for several weeks in a damp cellar and have an average test score of 86.6. The last seven samples were held in a dry but unheated room for a week before cracking and show an average test score of 83.7. The average score for the two soaked samples was 93.9. Soaking also increased the number of halves and quarters recovered in the same way as shown with variety Snyder in Table 2. None of these samples was excessively dry. In this table the lowest score (sample 19) is directly related to the presence of 3 empty nuts in the sample. The low score of sample 21 is mostly related to low per cent first crack which is caused by large number of bound quarters and the high penalty related to empty nuts and shrivelled kernels. These scores seem to indicate the value of the samples but bring out the difficulty of obtaining equal scores from such replicate samples. The other scores in the table are probably as close to each other as can be expected with samples of this sort.

In this and the preceding tables the number of bound quarters is given as an indication of cracking technique. With the Hershey cracker the nuts of many varieties will split into four quarters without releasing the kernels. The number of such bound quarters is increased if the operator does not put sufficient pressure on the anvils to crush the shoulders of the nut and free the kernel. On the other hand if too much pressure is used and the anvils brought too close together the kernels will be crushed and the score affected adversely. With some varieties, for example, the Adams as shown in samples 1 and 2 in table 5, the nuts are so pointed at each end that the standard anvils do not strike the shoulders of the nut and many bound quarters result. With such varieties cracking with a hammer would probably give a better score. Anvils with deeper cavities in the ends would be an advantage for such nuts.


Tests by the same operator of duplicate samples of Ohio black walnuts, treated in various ways before cracking. 25 nut samples. 1942 crop.

KEY: A: Wt. 1 nut grams B: % kernel 1st crack C: % kernel total D: Quarters number E: Penalty F: Score

Sample Treatment A B C D E F Remarks —————————————————————————————————————- 9 *Dry 16.9 25.8 27.1 98 -0.5 91.3 1 shr., 5 bnd. qtrs., 7 halves 10 *Dry 16.8 23.8 25.2 95 -3.0 83.5 1 empty, 4 shr., 7 bnd. qtrs. 12 *Dry 16.2 24.5 26.5 97 -2.0 86.1 4 shr., 8 bnd. qtrs., 13 halves 24 *Dry 16.2 24.8 25.7 86 -3.0 84.2 2 empty, 2 shr., 4 bnd. qtrs., 8 halves 17 *Dry 17.3 24.8 27.3 97 -0.5 89.7 1 shr., 9 bnd. qtrs., 12 halves 21 *Dry 15.9 22.0 25.5 96 -4.0 78.2 1 empty, 6 shr., 14 bnd. qtrs., 17 halves 8 *Dry 16.6 25.2 26.9 99 -1.5 88.8 3 shr., 6 bnd. qtrs., 10 halves 15 *Dry 16.6 25.5 26.7 99 -1.5 89.8 3 shr., 5 bnd. qtrs., 12 halves 23 *Dry 16.4 25.2 26.2 96 -3.0 87.0 6 shr., 4 bnd. qtrs., 10 halves 11 Soaked 16.9 27.0 28.2 100 -1.5 93.5 Soaked 1 hr., moist 18, dried 12 hrs., 3 shr., 5 bnd. qtrs., 25 halves 16 Soaked 16.8 27.1 28.2 100 -0.8 94.3 Soaked as above, 1 shr., 5 bnd. qtrs., 16 halves 4 Dry 16.2 23.6 26.4 98 -3.5 82.9 7 shr., 10 bnd. qtrs., 15 halves 5 Dry 17.1 23.6 25.0 93 -3.0 83.1 1 empty, 6 shr., 5 bnd. qtrs., 10 halves 18 Dry 17.0 25.3 26.6 97 -2.0 88.6 4 shr., 6 bnd. qtrs., 8 halves 19 Dry 16.3 21.5 23.7 85 -4.5 75.1 3 empty, 3 shr., 9 bnd. qtrs., 8 halves 3 Dry 15.4 24.7 27.0 97 -3.0 85.0 6 shr., 8 bnd. qtrs., 5 halves 7 Dry 16.0 25.7 25.7 94 -3.5 86.1 7 shr., 6 halves, end reversed in cracking 22 Dry 17.4 24.1 25.8 94 -2.5 85.4 5 shr., 8 bnd. qtrs. —————————————————————————————————————-


Variation in score of replicate samples of 3 varieties of Black Walnuts tested by different operators and of same varieties from different sources

Wt. 1 % kernel % nut 1st kernel Quarters Variety Source grams crack total number Score ———————————————————————————————————— Operator 1 Thomas—Weber, Ind. 20.4 20.8 24.2 75 81.6 Thomas—Jones, Pa. 14.6 28.8 30.3 95 96.8 Thomas—Baum, Pa. 14.3 25.6 27.0 100 89.0 Thomas—Worton, Md. 16.4 28.2 30.8 94 97.6 Average 16.4 25.8 28.1 91.0 91.2

Operator 2 Thomas—Weber, Ind. 22.0 22.2 23.8 47 83.0 Thomas—Jones, Pa. 17.5 26.7 31.4 55 92.1 Thomas—Baum, Pa. 17.0 24.0 26.5 72 85.5 Thomas—Worton, Md. 16.7 19.5 26.4 64 75.3 Average 18.3 23.1 27.0 59.5 83.9

Operator 3 Thomas—Jones, Pa. 18.1 16.2 27.1 52 69.2 Thomas—Baum, Pa. 16.1 19.1 26.6 68 74.4 Thomas—Worton, Md. 18.0 17.8 27.2 61 73.3 Average 17.4 17.7 27.0 60.3 72.3

Operator 1 Ten Eyck—Weber, Ind. 18.0 20.5 27.5 57 78.5 Ten Eyck—Jones, Pa. 15.4 21.1 23.2 99 79.1 Ten Eyck—Baum, Pa. 14.3 26.3 30.2 93 91.3 Ten Eyck—Worton, Md. 15.0 28.0 31.0 83 94.8 Average 15.7 24.0 28.0 83.0 85.9

Operator 2 Ten Eyck—Weber, Ind. 19.1 24.4 26.5 38 84.8 Ten Eyck—Jones, Pa. 16.4 24.6 24.6 64 84.3 Ten Eyck—Baum, Pa. 15.8 25.7 26.5 54 86.0 Ten Eyck—Worton, Md. 15.4 25.5 28.7 55 86.2 Average 16.7 25.0 26.6 52.7 85.3

Operator 3 Ten Eyck—Weber, Ind. 16.8 17.3 24.6 57 69.4 Ten Eyck—Jones, Pa. 15.2 21.1 23.3 84 77.4 Ten Eyck—Baum, Pa. 15.0 18.3 19.7 69 68.4 Ten Eyck—Worton, Md. 15.7 25.2 30.1 76 88.5 Average 15.7 20.5 24.4 71.5 75.9

Operator 1 Ohio—Weber, Ind. 17.2 28.5 29.7 89 98.0 Ohio—Jones, Pa. 16.4 28.7 29.9 96 99.2 Ohio—Baum, Pa. 14.2 31.1 31.1 99 101.9 Ohio—Worton, Md. 13.7 30.8 30.8 88 99.5 Average 15.4 29.8 30.4 93.0 99.6

Operator 2 Ohio—Weber, Ind. 19.1 25.1 28.3 59 89.3 Ohio—Jones, Pa. 17.2 27.3 27.5 64 91.9 Ohio—Baum, Pa. 15.0 27.4 28.1 63 90.1 Ohio—Worton, Md. 14.9 26.1 29.1 58 87.4 Average 16.5 26.5 28.2 61.0 89.7

Operator 3 Ohio—Weber, Ind. 17.7 21.4 27.7 65 80.8 Ohio—Jones, Pa. 17.2 22.9 28.2 74 84.5 Ohio—Baum, Pa. 15.0 24.9 29.3 81 87.5 Ohio—Worton, Md. 14.6 22.4 28.7 66 80.3 Average 16.1 22.9 28.5 71.5 83.3 ————————————————————————————————————

Table 4 gives the results of tests of similar samples of three varieties from four different sources by three different operators. The tests are not satisfactory because pretreatment was not uniform and there is insufficient data on penalties which are omitted. Some samples of the varieties Ten Eyck and Thomas contained empty nuts and shrivelled kernels which would preclude equal scores. The variety Ohio was uniformly filled from all sources. In the variety Ten Eyck there is a difference of 10.5 per cent in total per cent kernel in samples from the Baum orchard. This was related to 6 empty nuts in the sample cracked by operator 3. In the variety Ohio in which the kernels were plump the greatest variation between duplicate samples in total per cent kernel is 3 or only about 10 per cent of average total per cent kernel.

An examination of these data show the following points of interest: (1) that the duplicate samples showed considerable variation in weight of single nut and total per cent kernel, characters not dependent on personal skill or judgment. Operator 2 did not crack the whole sample of 25 and may have selected the larger nuts, thus securing a greater weight per nut with all varieties. The superior filling of the nuts of Ohio appears to be related to the fact that in the orchards in question this variety was observed to hold its leaves longer than the others which lost their leaves in late summer before harvest by leaf blight. Shrunken kernels are a logical result of early defoliation.

In the per cent of kernel obtained in first crack operator 1 recovered a higher per cent than operator 3 in all of the eleven possible comparisons and higher than operator 2 in 9 out of 12 possible comparisons. This probably is the result of soaking the samples by operator 1 and not by the others or possibly due to greater skill or care in cracking. The number of quarters recovered by operator 1 is greater in all cases than that obtained by either operator 2 or 3. This is also a result of soaking or skill or both. The score of operator 1 was in all tests of duplicate samples higher than that obtained by operator 3 and higher than the scores of operator 2 in 9 out of 12 comparisons.

The scores of the different samples are apparently mainly determined by the per cent recovered at first crack and the number of quarters, at least the only cases where the scores of operator 2 exceed those of operator 1 are where the per cent first crack and the number of quarters are greater for operator 2. This is related to the presence of empty nuts.

The data obtained for the variety Thomas by operator 1 and 2 show for the most part the same relative scoring of samples from different sources. For example with both operators the score of the samples from the Weber orchard was lower than that from the Jones and Baum orchards and the sample from the Jones orchard scored higher than that from the Baum orchard. In the samples from the Worton orchard the relative scores are reversed. The scores oL operator 3 are quite out of line. With the variety Ten Eyck the differences between scores of samples from different sources are not consistent. Operator 2 obtained scores that were essentially alike for all four samples whereas the scores of operator 1 show differences of more than 10 points. This is related to empty nuts in the sample. With the variety Ohio there is reasonable uniformity in the scores obtained by all operators. This was the only variety with well filled nuts and for that reason alone the score would be less variable.


Tests by different operators on duplicate samples of black walnuts, soaked and unsoaked. 25 nut samples. 1942 crop.

KEY: A: Treatment B: Wt. 1 nut grams C: % kernel 1st crack D: % kernel total E: Quarters number F: Penalty G: Score

———————————————————————————————————————- Sample A B C D E F G Remarks ———————————————————————————————————————- Operator 1

Ohio No. 1 Dry 16.8 26.1 27.6 97 -4. 88.5 5 bnd. qtrs., 18 shr., 8 halves Ohio No. 2 Soaked 16.7 27.3 27.8 99 -1.5 93.5 2 bnd. qtrs., 1 shr., 1 empty

Operator 2

Ohio No. 6 Dry 15.9 26.3 26.7 93 -1. 90.2 1 empty Ohio No. 13 Soaked 15.9 25.8 26.4 93 -1. 89.0 1 empty Ohio No. 14 Soaked 15.7 25.2 26.3 96 - .5 88.4 1 shriveled Ohio No. 20 Dry 16.7 25.3 26.4 94 -1. 88.9 1 empty

Operator 1

Grundy No. 1 Dry 23.8 24.1 24.6 99 - .5 93.7 1 shriveled, 2 bnd. quarters Grundy No. 2 Soaked 23.2 24.2 24.2 100 - .5 97.2 All out 1st crack, 5 halves

Operator 2

Grundy No. 3 22.4 24.0 24.0 88 -2. 89.2 Empty Grundy No. 4 Dry 23.5 24.7 25.5 98 - .5 95.0 1 shriveled

Operator 1

Adams No. 1 Dry 14.2 18.3 24.5 70 0. 70.0 35 bnd. qtrs., well filled, good quality Adams No. 2 Soaked 14.4 17.3 23.7 78 -2.5 67.1 2 empty, 20 bund. qtrs., 1 shr.

Operator 2

Adams No. 3 Dry 14.6 18.1 24.0 77 -3. 67.5 3 empty Adams No. 4 14.3 19.6 25.4 78 -2. 72.3 2 empty ———————————————————————————————————————-

The average scores of all samples of each variety are Ohio 90.0, Thomas 83.4, and Ten Eyck 82.4. These are not out of line either with the scores obtained for these varieties elsewhere or the relative merit of the varieties.

Because of the variability obtained in the tests shown in Table 4, another series of tests of similar samples by different operators was arranged in the summer of 1943. The samples of Ohio were some of the same lot reported in Table 3. The varieties Grundy and Adams grown in Michigan were carefully sampled to give comparable lots. The results of these tests given in Table 5 show no greater variability between the scores of the two operators for any one variety than between tests by the same operator and indicate that it is possible for different operators to obtain comparable scores on duplicate samples provided great care is used in treating and cracking the samples.

The differences in average score between the different varieties is consistent and apparently gives a correct indication of their relative merit. Grundy shows an average score of 93.7, Ohio 89.7 and Adams 69.2. The high score of Grundy is related to the large size of nut and high per cent first crack. The low score of Adams is related to small size of nut and low per cent first crack resulting from a large number of bound quarters. The kernels of this variety were plump, filling the cavity of the shell full and shattered on cracking.

In Table 6 are given the results of 54 tests of 38 selections or clones. In general it appears that the score is a fair indication of the worth of the sample. Low scores are related mostly to low per cent first crack and to the presence of empty nuts or shrivelled kernels in the sample. It is evident also that if a sample is too dry with many varieties a low score will result. Just what soaking treatment is most expedient is not too clear. Soaking 12 hours and drying 24 proved to be a satisfactory practice. The method followed by Mr. Stoke of soaking for 5 minutes and keeping the sample in a wet burlap sack for 24 hours is all right but is cumbersome if many samples are to be tested. Soaking one hour and holding 24 hours in a closed container like a coffee can give good results but percentage should be figured on dry weight and kernels should be air dried for 24 hours before weighing.

One weakness in the schedule is that it tends to give a small nut an advantage if the per cent kernel obtained in first crack is high. Thus a sample of the Mintle grown in Iowa which weighed but 13.6 grams per nut and total per cent kernel of 32 scored 101.1 points chiefly because the per cent first crack was 31.5. The same variety grown at Ithaca weighing 13.7 grams per nut but with 23.9 per cent first crack and 24.3 total scored 83.8. Possibly a penalty could be taken for nuts weighing less than 18 grams. On the other hand a large nut like the Grundy weighing about 23 grams would have a 10 point score advantage over Mintle and this may be enough for this character.

The six samples of Thomas grown on different trees in Ithaca, N.Y. in 1942 show great variation in score as has been the case in other years. Poor scores are related to shrunken kernels and such samples come from trees that are making poor growth because of poor soil conditions and competition with weeds. Also shriveled kernels are the result of defoliation by early frosts which may be very local and affect some trees and not others.


Tests and Scores of Black Walnut Varieties from Various Sources. 25 nut samples unless otherwise indicated. All scores figured on basis of 25 nuts.

KEY: A - *Treatment D—Dry S—Soaked No.—Hours dried or soaked B - Wt. 1 nut grams C - % kernel 1st crack D - % kernel total E - Quarters number F - Penalty G - Score

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