Factors Affecting Nut Tree Propagation

I don't want you folks to get the idea we have these parent trees or seed from them that are available. I mention it because a lot of you are growing chestnut trees and planting them from seed. You could make a great contribution if you would take the nuts from each individual tree and plant separately, so that you will know in the future the origin of every one of those seedling trees you have. Some of these days someone is going to find one that is going to give us seedling trees that are good and free from variation.

Elberta peach seed will come practically true to variety from seed, except minor variations of size, shape, color and season. In a peach you are facing a very highly specialized market. But with the Chinese chestnut, color is not so important. What we are interested in is trees that bear and have enough uniformity so that we don't have pee-wees by one and jumbos by another.

We need very badly this sort of thing. We need chestnut varieties planted in pairs in isolated places. Any of you folks could do a great service if you will let us know wherever trees occur in pairs, or just two varieties and no others, and then we know that one variety pollinates the other. When you have a mixed planting of a half dozen varieties the male is promiscuous. Therefore you have a much greater mixing of genetic factors. If we have a pair of trees, we get a much more uniform breeding group of seedlings.

MR. O'ROURKE: I think we can go to vegetative propagation of cuttings. I think that we have any amount of evidence that Chinese chestnuts can be rooted from cuttings, but can trees grow on from rooting cuttings?

MEMBER: Just by accident, in our storage house a couple of chestnuts fell over into a pile of peat moss and they did make roots.

MR. O'ROURKE: We should confine this only to propagation. While there are any number of interesting phases of it, we have to stick to propagation or we will never get through. We have had remarks on layers. Any comments on layers?

Let's move on to graftage. We want to have our chestnut produced on a quantity basis so I am going to ask Mr. Bernath to tell us a good method.

MR. BERNATH: I don't graft too many outside, but I do my propagating in the greenhouse. I had more than a thousand graftings growing, some of them this high [indicating] which greatly depends upon the root system and the condition of the soil. I think that is the fastest and easiest way of grafting chestnuts. I do my grafting sitting down.

MEMBER: After you have produced all these grafts, what are you going to do with them?

MR. STOKE: I tried to contact some nurseries. They are selling your seedlings, little chestnut trees for $1.75 and they want to give you 75¢ or a dollar for grafted ones.

MR. O'ROURKE: Mr. McDaniel has received a letter from Mr. Hirschi from Oklahoma City and there is one paragraph that I think the membership will be interested in. [Letter from Mr. Hirschi is partly reproduced here.]

Oklahoma City, Okla.
Aug. 23, 1951

Mr. J. C. McDaniel,
Urbana, Ill.
My Dear Mac;

... In my work with chestnuts I believe I have had an experience that will be interesting to the membership. As you well know I am a strong believer in selected named varieties. I do not regard seedling chestnuts any more valuable than seedling peaches or apples. The—Nursery, a member of our association, have been customers of mine for a long time. Last year I persuaded them to catalog seedling chestnuts at about half the price of Nanking, Meiling, Kuling, and Abundance. I was anxious to learn the attitude of the public, where they had an opportunity to buy and plant selected grafted varieties, when heretofore only seedlings were available. To my utter amazement the seedlings did not sell at all, but the thousand trees of selected varieties were sold out long before the season was over. I could not supply more, neither could I get them elsewhere. So far as I know Max Hardy and I are the only ones grafting chestnuts in quantities.

It is amazing the volume of business that catalog nurseries do. For instance the above firm does a million dollars gross business annually, and many others do a big business. All would be glad to catalog grafted chestnuts, and the chestnut movement would grow by leaps and bounds. True, they would have to be sold to them at wholesale prices, but they want small sizes, parcel post sizes preferred, which can be produced the second year from seed. Plant the seed in March, the next March graft them, and by fall the grafts will range from three to seven feet as shown by the enclosed photos.

I had the same experience with the above firm with Carpathians, sold them 500, which were sold out long before the season ended and I could not get them any more. They have ordered 2500 for this coming season. Unfortunately we had a poor take on grafts this spring due to cutting scion wood after a November freeze, which killed all other English walnuts. Carpathian wood was not hurt except where used for scions. Where left on the trees they forced out as usual and are producing a good crop of nuts.

I must close. I know you will have a wonderful meeting and I wish I could be with you. I will be with you in spirit, and in the meantime will be doing all I can to promote interest in nut growing.—Very truly yours, A. G. Hirschi.

MR. GERARDI: I don't yet have the greenhouse. I depend on field grafting. I produce my own seedlings. I just use seed from those three best trees. They run pretty uniform as far as growth is concerned. I bark graft in the field, when the buds begin to swell nicely and from there on. You can get a growth like that. [Indicating four to 5 feet.]

MEMBER: He has the same thing. Just as soon as the buds swelled. Sometimes I do go to the trouble if I am covering more ground, to cut them off as soon as they start to swell. A chestnut will peel again in four days. I start in after about four days and set these grafts and I use this bark graft. I have a sample of the method here. This is the plain bark graft which is efficient and fast for the production of chestnuts in quantity. I have to get into bigger production. I am trying to make speed and I am using this method. To start, the first week of April, when the buds start. If I get it done, it's the first week or the second of April.

MR. GERARDI: Four days on chestnuts. In my personal opinion after a few years observation I don't believe it is absolutely essential to cut back. Sometimes weather conditions will be a big factor. Sometimes the temperature is around forty and remains that way four or five days. The weather has taken the place of your cut back. That doesn't always happen, but weather conditions sometimes favor this.

MR. GERARDI: Well, it is better to take a thousand trees. Out of a thousand you miss 35 or 40. The percent that takes is high. This is an important factor; you must have good wood. You are running just a little on the small size. From a quarter of an inch up to—. I never set a scion over about 9/16. That is just getting into the rough ... It's hard on the tool and rootstocks.

MR. GERARDI: Yes, if favorable weather permits. I use this Acme compound. Last season, it was a little stiff and I mixed a little oil and it cut my rubber bands too quick. That brush wax is about as good as you can get, but customers come in and I am called away and someone is always interfering with the work. I was trying to get a wax that I could just drop and it would be ready when I picked it up again. It is beginning to be an assembly line production. You can go faster if you have a helper or two to do the tying and waxing.

MEMBER: I have a rather crude scion storage method. I have dug out in a hill a reservoir that I keep ice in. If you could keep it at 32 to 40 degrees from the time it is cut in February, or the first part of March and then store it in this until the grafting time, it will keep readily.

MEMBER: In California I built a little house and there was room enough to put in at least 40 bushel boxes, 900 pounds of ice and I packed grafting wood in boxes and kept it until July.

MR. WILKINSON: I have had very little experience in propagation of chestnuts. Mine has been limited. I shoulder my scions. I like to shoulder. My percentage of take varies with the conditions, sometimes it's fairly good and sometimes not so good. I have a specimen union of two inches in diameter and you can see what a nice union it makes. Ordinarily I have had very good success with chestnut grafting.

DR. McKAY: We have done some work on budding chestnuts but it hasn't been successful. We have had indefinite results. As Mr. Stoke says, grafting is so much more simple. We realize more work should be done on budding. We simply do our propagating the way it is easiest. Until the time comes that we have got more information on budding we will go along as we do now. One of the difficulties is that the wood is fluted and it is hard to get a good bud fit. It doesn't make for a good fit. We carried out a little experiment on one year old seedling at the crown. There is a smooth area on the stem as it enters into the root condition. It is a perfectly smooth area and we tried putting sealed buds at that point. We have had good success in putting those kinds of buds in at the time when you would ordinarily bud fruits, in the fall, where growth conditions are still good. Another year we did that same work and we didn't succeed so well. So we don't know exactly what we did wrong. In order to keep a set from those buds we don't know just what the conditions should be.

MR. O'ROURKE: To summarize then, the two successful methods are the greenhouse method and the field method used by Mr. Gerardi.

MR. STOKE: I mostly use a plain splice. The cut is about four times as long as scion diameter, if it is on a stock of the same size. It is the best method. I use also a modified cleft graft with a little trimming. Mr. Jones brought out that modified cleft graft and I have made a little change. Here is the stock, and a modified cleft graft is a side graft with the stock top cut off. You cut in at an angle far enough and you put your scion in here and there is your modified cleft graft. You get contact on all four lines. It takes experience and judgment. You cut your scion wedge and then make your understock cut and you will seldom make a mistake after you get experience. That is a side graft and a modified cleft graft. That makes a flexible portion here and you get a fit on both sides. But with the ordinary cleft graft, if you go to the end of your stock you still have a split and not a perfect fit.

MEMBER: Would you explain that? If your scion is not the same size it might over lap or ... how do you handle that?

MR. STOKE: If the scion is undersized, you don't cut so deep. Sometimes the stock is a little oversize. You simply cut less deep in your stock. If you have a large stock and small scion I'd make a bark graft.

MEMBER: I should like to bring up one point. That is produce more nut trees and do it cheaper. It seems to lie between Mr. Gerardi and Mr. Bernath. Mr. Gerardi can set between six and seven hundred per day, and tie them himself, and Mr. Bernath will graft between seven hundred and a thousand a day with someone else doing the tying.

MR. CHASE: We have tried all these grafting methods with varying degrees of success. Our propagation experiments at Norris have been directed at the development of more economic methods.

Conifer grafts are often placed in a grafting case for rapid callusing. This year we tried some black walnut grafts and found that they callused in 10 to 14 days when placed in a grafting case. These were bench grafted on piece roots, using modified cleft and side grafts. Later we tried chestnut with excellent results. Then we made more chestnut grafts, wrapped them in damp moss and placed them in a lab oven with a temperature of approximately 75 degrees. These callused rapidly and were planted immediately in the nursery. They made good growth.

We think that some adaptation of this method has possibilities in our region. Often our chestnut grafts are damaged by late spring frosts. If we can bench graft, callus, and then hold the grafts until favorable weather, frost damage will be eliminated. It may be possible to handle black walnut in some similar fashion. Then we would be dealing only with successful grafts. A cold frame provided with heating cable should be adequate.

Factors Affecting Nut Tree Propagation

Propagation by Cuttings

Gellatly (7) quoted the success of the East Malling Research Station in England in rooting cuttings of walnuts grown in the greenhouse and reported on his own experience in producing short roots on dormant cuttings of heartnut and Persian walnut. The writer (15) has occasionally produced roots on softwood cuttings of pecan and hickory set in a mist humidified greenhouse but the cuttings did not survive. Mist humidification has been a distinct aid in retaining foliage on softwood cuttings of filbert and Chinese chestnut until roots were formed but unless the axillary buds were developed sufficiently to make new growth immediately thereafter, little or no survival was secured. Apparently when the cuttings were succulent enough to form roots the buds were too immature to put out new shoots. If one waited until the buds were developed the tissue at the base of the cutting was too highly lignified for root formation. The use of synthetic plant hormones on cuttings of nut-tree species has been of questionable value.

Propagation by Layers

Mound layers are used quite successfully for the propagation of filbert varieties but have not proven of value with other nut-tree species. Chinese chestnut has been reported to layer easily but experiments with both mound and trench layers of selected varieties of this species at the Glenn Dale, Maryland Station of the U.S. Department of Agriculture gave negative results. The writer (15) has occasionally rooted pecan, hickory, and Chinese chestnut by aerial layering. A marcot box containing sphagnum moss kept moist by a glass wick immersed in water from a bottle at the lower end was employed. The time and labor involved were so great that the experiments were discontinued.

Propagation by Grafting

Bench grafting of walnuts and hickories has been adequately described by Bernath (3), Hardy (8), Lounsberry (10), Slate (24), and others. This method has been tested on a commercial basis and apparently should be considered as one of the most efficient ways to produce nut trees quickly and cheaply in large quantities. Greenhouse and storage facilities are required and keen expert attention must be given the newly-made grafts to assure success.

Reports on top-working and field grafting are both numerous and voluminous. Morris (13), MacDaniels (11), Wilkinson (29), and others have demonstrated the value of cutting back the stock a week or more before setting the scion in order to avoid injury from excess flow of sap. Reed (17), Stoke (27), Morris (14), Shessler (21), Sitton (23), and others have described methods of preparing and setting scions in the stock. All writers agree that greater success is secured when dormant scions are set relatively late in the season. Becker (2) stated that greater success was secured when scions were set from time leaves were full-grown until catkins fell. Protection of the scion by waxes, paper bags, and shading has been advocated by Morris (14), MacDaniels (11), Shelton (20), Shessler (21), and others.

Propagation by Budding

The shield or T bud has not been considered suitable for thick-barked trees such as hickory and walnut due to the difficulty of preventing "air-pockets" beneath the bark. Shaving the edges of the bark at the side of the shield may eliminate this difficulty. Joley (9), reported variable success in shield budding of walnut in California. Patch budding, either by the annular method or with the Jones patch-budding tool was described by Reed (17), and is reported by Chase (6), Zarger (30), and others to be the most practical method of propagation with walnuts. Pecans and hickories are commonly patch-budded in summer in commercial nurseries. The thin-barked Chinese chestnut is usually budded by the shield-or T-bud method as reported by Hardy (8) and McKay (12).

Scion and Budstick Handling

Sitton (22) reported that two-year wood of black walnut was superior to either older or younger wood. MacDaniels (11) advocated the base of the scion to be in the two-year wood and the tip in the one-year wood.

Shelton (19) reported that scions could be kept moist until used by storing in a closed container with a small amount of sodium sulphate, commonly known as "Glauber's salt". The usual method of scion storage is to pack in moist but not wet peat or sphagnum moss and place in a refrigerator at about 35° F. Waxes and resins have been used successfully to prevent undue loss from the plant tissues while in storage.

Waxes and Dressings

Propagators seldom agree in their choice of a wax and wound dressing. In a series of carefully controlled tests, Sitton (23), found that a rosin and beeswax mixture with a filler gave results with pecans superior to the so-called "cold waxes" or asphalt emulsions. Paraffin and polyvinyl resin are often used for scion covering and to protect newly set buds. Shelton (20) has indicated certain qualities of a satisfactory wax.

The Rootstock Problem

In the Pacific Northwest Painter (16) stated that some Persian walnut varieties on Juglans hindsi (the northern California black walnut) develop a fatal graft blight due to delayed incompatibility at about 20 years of age. This is the so-called black-line disease. McKay (12) found great differences in survival of buds of Chinese chestnut placed on five seedling strains and Hardy (8) suggested that more attention should be paid to the parental relationship of stock and scion in the chestnut. Weschcke (28) reported that black walnuts grafted on butternuts yielded poor crops and that bitternut was a satisfactory stock for shagbark varieties and shagbark hybrids. Smith (25) advocated shagbark stocks for shagbark varieties but found bitternut to be practically as good. Stoke (26), and Smith (25) found eastern black walnut to be the best stock for all walnut species, including heartnuts and butternuts.

Nursery Practices

Commercial nurseries have adopted various methods to discourage the normal tap-rooting habit of nut trees and stimulate lateral and fibrous root production. Planting seed over screen wire, undercutting the seedling each year in the nursery row, frequent transplanting, and root pruning are methods commonly used. Attention must be given to the production of an adequate root system to help the grafted tree withstand the shock of transplanting to its permanent location.

Summary

The chief obstacle to the large scale growing of selected nut varieties is the difficulty in propagation. Careful workers with a background of knowledge and experience and skilled in craftmanship are successful in a limited way. Quantity production is apparently dependent upon specialized facilities and efficient labor programs. The need for extensive rootstock research is keenly felt by growers of walnut, hickory and chestnut.

Literature Cited

1. Barton, Lela V.—Seedling Production in Carya ovata, Juglans cinerea, and Juglans nigra. Cont. Boyce Thompson Inst. 8:1-5. 1936

2. Becker, Gilbert—Notes from Southwestern Michigan. Rept. North. Nut Grow. Assoc. 28:135. 1937

3. Bernath, Stephen—Propagating Nut Trees under Glass. Rept. North. Nut Grow. Assoc. 37:90. 1946

4. Chase, Spencer B.—Black Walnut Nursery Studies. Rept. North. Nut Grow. Assoc. 37:40-41. 1946

5. Chase, Spencer B.—Eastern Black Walnut Germination and Seedbed Studies. Jour. For. 45:661-668. 1947

6. Chase, Spencer B.—Budding and Grafting Eastern Black Walnut. Proc. Amer. Soc. Hort. Sci. 38:175-180. 1947

7. Gellatly, J. U.—Notes on Nuts and New Combinations of Old Principles. Rept. North. Nut Grow. Assoc. 29:115-120. 1938

8. Hardy, Max B.—The Propagation of Chinese Chestnuts. Rept. North. Nut Grow. Assoc. 40:121-126. 1949

10. Lounsberry, C. C.—Bench Grafting of Black Walnuts. Rept. North. Nut Grow. Assoc. 28:60. 1937

11 MacDaniels, L. H.—Some Experiences in Nut Tree Grafting at Ithaca, New York. Rept. North. Nut Grow. Assoc. 28:52. 1937

12. McKay, J. W.—Results of a Chinese Chestnut Rootstock Experiment. Rept. North. Nut Grow. Assoc. 38:83-84. 1947

13. Morris, R. T.—Top Working Hickories—Rept. North. Nut Grow. Assoc. 11:105. 1920

17. Reed, C. A.—Nut-Tree Propagation. U.S. Dept. of Agr. Farmers' Bul. 1501. 1926

18. Reed, C. A.—Seedling Chestnut Trees versus Grafted Varieties. Rept. North. Nut Grow. Assoc. 32:79. 1941

19. Shelton, E. M.—Glauber's Salt for Humidity Control in Scion Storage. Rept. North. Nut Grow. Assoc. 28:70-71 1937

20. Shelton, E. J.—A Laboratory Experience in Testing Wax Mixtures for Use in Plant Propagation. Rept. North. Nut Grow. Assoc. 28:72-75. 1937

21. Shessler, Sylvester—Grafting Walnuts in Ohio. Rept. North. Nut Grow. Assoc. 39:145. 1948

22. Sitton, B. G.—Vegetative Propagation of the Black Walnut. Mich. Agr. Expt. Sta. Tech. Bul. 119. 1931

23. Sitton, B. G.—Pecan Grafting Methods and Waxes. U. S. Dept. Agr. Circ. 545. 1940

24. Slate, George L.—Grafting Walnuts in the Greenhouse. Rept. North Nut Grow. Assoc. 39:146-147. 1948

25. Smith, Gilbert L.—Our Experience with Rootstocks. Rept. North Nut Grow. Assoc. 40:62-64. 1949

26. Stoke, H. F.—Nut Nursery Notes—Rept. North. Nut Grow. Assoc. 34:96. 1943

27. Stoke, H. G.—Grafting Methods Adapted to Nut Trees. Rept. North. Nut Grow. Assoc. 37:99-102. 1946

28. Weschcke, Carl—The Importance of Stock and Scion Relationship in Hickory and Walnut. Rept. North. Nut Grow. Assoc. 39:190-195. 1948

29. Wilkinson, J. F—Preparation of Stocks for Propagation. Rept. North. Nut Grow. Assoc. 28:65-66. 1937

30. Zarger, Thomas G.—Nut-testing, Propagation, and Planting Experience of 90 Black Walnut Selections. Rept. Nut Grow. Assoc. 36:23-30. 1945

Nut Rootstock Material in Western Michigan

My first experience with rootstocks for grafting came about in 1926 when I was working at the J. F. Jones Nursery then at Lancaster, Pennsylvania. Mr. Jones used both bitternut and pecan seedling stocks for grafting shagbark hickories. Pecans and hicans were also grafted on hardy northern pecan seedlings, and Japanese walnut stocks were used for butternuts and heartnuts. Black and Persian walnut scions were set on eastern black walnut seedlings.

When I returned to Michigan I brought back enough of Mr. Jones' trees for a small test planting here at Union City. These trees were planted in a heavy quack grass sod and some were lost, but those surviving show good compatibility between the top and root.

In the intervening years I have made but slight changes in the rootstock material used in my own nursery. I do not approve of the performance of our butternut varieties on the Japanese walnut root, as it results in a weak and dwarfed tree. The use of butternut rootstocks is also unsatisfactory, for they tend to produce trees of low vitality that in a few years fall victim to blight and then perish. I tried our Michigan black walnut seedlings as a rootstock and found that they are very much better rootstock material. The growth at the union is about equal. Top growth is good, and the butternut tops bear early and heavily, with no signs of blight during the ten years I have had them under test.

After years of test I have decided to use the northern pecan seedlings as rootstocks for my shagbarks, pecans, and hicans because they are a fast growing stock tree. They accept the grafts readily, and make good unions more quickly than the bitternut stocks I have tried. Mr. Wilkinson, from whom I obtain my seed, has never failed to send me seed with good viability, just about every seed germinating. The northern pecan seedlings have shown no winter injury here in Southern Michigan during the 20 years I have watched them growing.

An example of the superiority of the black walnut over the Persian walnut as a rootstock is a seedling of the variety Wiltz Mayette growing near a Broadview grafted on black walnut. Both trees are the same age, but the Broadview on black walnut is just about twice the size of its own-rooted neighbor.

Hudson Valley Experience with Nut Tree Understocks

Our first year's grafting was done in a plot of practically pure pignut stocks. This was the seven leaflet pignut, which I believe to be Carya glabra. I have never been sure of the identification of the two species of pignuts. We secured a fairly good percentage of living grafts, which grew well the first summer. The next spring all of the grafts failed to leaf out and later were found to be dead. A few grafts which were put on bitternut stocks (Carya cordiformis) grew well, and are still growing well after more than fifteen years. Several different varieties of shagbark hickory scions were used in this grafting.

The second year, we again grafted as many or more stocks in this same area. The results were exactly the same, except that we used some scions of Davis and Fox. (These varieties were brought to light through the contests of the previous winter). The grafts of Davis grew on pignut stocks, are still alive and doing fairly well. They have been bearing for several years, although the squirrels have stolen all of the nuts. Grafts of all other varieties which were on the pignut stocks died the next spring. One graft of Fox on mockernut lived and has continued to grow fairly well. That same year we started our test orchard of shagbark stocks (Carya ovata) in a different area. Grafts on these stocks have grown very well.

I believe that for some reason grafts of shagbark on pignut stocks cannot stand cold weather. Certainly, incompatibility is very marked.

Pignut (Carya glabra or possibly Carya ovalis). This species is worthless as a stock for shagbark, shellbark, and hybrids of these species. If nut growers have some pignut stocks growing where they especially wish to have some good hickory trees, they can graft them to Davis. We have also heard that Brooks will grow on pignut stocks.

Mockernut (Carya alba). This species is also nearly worthless as a stock for shagbark, shell bark, and hybrids, although many more varieties will live on it than will on pignut stocks.

Shagbark (Carya ovata). This species makes the most dependable stock of any we have tried so far, for shagbark, shell bark, and the hybrids. Its greatest drawback is the long time it takes to grow seedlings to a size large enough to graft.

Shellbark (Carya laciniosa). We have never had an opportunity to use this species as a stock. I think that it would make a good one and possibly be faster growing than shagbark.

Bitternut (Carya cordiformis). We have found that this species makes a very satisfactory stock for shagbark and hybrid grafts. We have not tried shellbark on it, except Berger which grows well on it. Seedlings of this species are much faster growing than are shagbark seedlings, and thus are large enough to graft sooner. We have grafts growing on bitternut stocks since 1935, they are growing and producing well. We consider this species as good or nearly as good as shagbark as a stock.

We have received contrary reports from farther south. These may be due to stock being blamed for something they did not cause or it may be that bitternut stocks grown from seed of more southern origin may not be as good as our northern stock.[18]

Pecan (Carya pecan). Our experience with this species as a stock is very limited and has been confined to grafts of only one variety of shagbark (Wilcox). Results were very disappointing, but we have been told by others that it makes a good stock. It is much faster growing than is shagbark.

Walnut

In walnut grafting, we have found that the eastern black walnut stocks are so much superior to any others we have been able to find, that we have discarded all others.

Butternut (Juglans cinerea). We have found that it is much harder to secure living grafts on this stock than on black walnut. It also attracts butternut curculio to the nursery.

Japanese Walnut (Juglans sieboldiana and variety cordiformis). We have found that seedlings grown from either of these species are a great attraction to the butternut curculio. They are more difficult to secure living grafts on, and grafts on these stocks are very definitely less hardy than similar grafts on black walnut growing side by side. We have proved this repeatedly.

Persian Walnut (Juglans regia). We have never used this species as a stock, and in view of the fact that grafts of it grow so well on black walnut stocks, I can see no use in even trying it.

Eastern Black Walnut (Juglans nigra). As stated above, we have found this to be the ideal stock for all walnut grafting. It is more free from insects than any of the other walnuts. Grafts grow well on it and are more hardy than grafts on some of the others.

We have not had enough experience in grafting chestnuts and filberts even to offer any comment as to stocks for them.

FOOTNOTES:

[18] The planting location perhaps has more influence than the seed source. At any rate, the poorest growing pecan in the University of Illinois orchard is on a Wisconsin bitternut understock.—J. C. McD.

The 1950 Persian Walnut Contest

Entry 012: This is the Jacobs variety which placed third in the 1949 contest. The nut which produced this tree originally came from Germany some 70 years ago. It has withstood 15 degrees below zero without injury. This is a large tree which has been bearing since 1915. It produced 300 pounds in 1947; 100 pounds in 1948; 200 pounds in 1949; and 200 pounds in 1950.

Entry 006: A Carpathian originally obtained through the Wisconsin Horticultural Society in 1936 (Rev. Crath's selections). In 1950 it was 14 years old, 25 feet high, with a circumference of 30 inches. It has withstood 10 degrees below zero without injury. This tree began bearing in 1949; in 1950 it produced 15 pounds of nuts.

It should be emphasized that this contest was based entirely on nut characteristics. In another year the placing of the same entries might be considerably different, because of seasonal variation. However, it is significant that the McKinster, Hansen, and Jacob varieties which were among the prize-winners in the 1949 contest were also among the prize-winners in 1950.

Contests such as this are valuable as a first step in the selection and development of improved varieties. The prize-winners and those given honorable mention are all very promising hardy Persian walnuts. The next step will be to test these selections to determine their adaptability to our varying conditions.

Colby, a Hardy Persian Walnut for the Central States

The COLBY Persian walnut, named in August 1951, and released to nut nurserymen for propagation early in 1952, is the best to date of thirteen Carpathian seedlings (each from a different parent tree) planted at the University of Illinois Agricultural Experiment Station from 1937 to 1939. It is the first Persian walnut variety to be named at this station.

The name, Colby, honors Dr. Arthur S. Colby of the Department of Horticulture at the University of Illinois, who has been in charge of nut investigations here since 1919. It was given to this variety, with his permission, by members of the Northern Nut Growers Association during their 42nd Annual Meeting, held at Urbana in August, 1951. Dr. Colby is a former president of the Northern Nut Growers Association.

Colby is a seedling of the tree designated as Crath No. 10. The seed was collected in 1934 from the parent tree near Cosseev, in the Carpathian mountain region of southern Poland as then constituted, planted in the nursery of S. H. Graham, Ithaca, New York, and the seedling transplanted to Urbana, Illinois at the age of two years. It has been fruiting annually here since 1942, with crops of up to 1-1/4 bushels in recent years. The accompanying cut shows nuts of the 1951 crop, a little less than 2/3 natural size. They are thin shelled, like the parent Crath No. 10, well filled with kernels of rich flavor, and are medium in size for varieties of this species.

Prize	Entry	Submitted By	Nut Weight	Kernel Weight	Kernel Percentage
1.	030	Mrs. W. H. Metcalfe, Webster, New York	11.9	6.5	54.5
2.	011	(Hansen) S. Shessler, Genoa, Ohio	.8	5.8	58.5
3.	002	(McKinster) Roy McKinster, Columbus, Ohio	12.5	6.4	51.2
4.	012	(Jacobs) S. Shessler, Genoa, Ohio	12.9	6.0	47.0
5.	006	Lewis Weng, Dayton, Ohio	12.4	6.4	51.9

	Honorable Mention
	001	Mrs. Gale Harrison, Pemberton, New Jersey	14.7	6.2	42.2
	008	A. C. Orth, Dayton, Ohio	14.7	6.7	45.8
	014 (Burtner)	Fayette Etter, Lemasters, Pennsylvania	10.4	4.6	44.4
	016 (S-66)	G. L. Smith, Millerton, New York	15.1	6.8	44.9
	025	P. F. Countryman, Ontario,	13.9	6.3	45.3
	031 (Colby [19])	A. S. Colby, Urbana, Illinois	10.8	5.9	54.1
	032 (S-M-9)	Royal Oakes, Bluffs, Illinois	15.8	6.6	41.5
	033	S. Elwell, Homer, Michigan	19.2	8.3	43.2