L. H. MacDANIELS and S. S. ATWOOD, Cornell University
All its members would agree that the Northern Nut Growers Association should have an officially accepted schedule for judging black walnuts and the other kinds of nuts with which it is concerned. Some yardstick is needed to serve as a basis for the comparison of varieties which the members of the Association will use. Persons familiar with nut varieties are freqeuntly asked to answer questions about the best varieties to plant. Of course there is no simple answer to such a question as many factors besides the nuts themselves determine the value of a variety. The quality and value of the nuts are, however, the most important initial consideration in selecting a variety on its merit and there should be some objective test adopted to aid in evaluating nut samples.
During the many years that the Northern Nut Growers Association has been operating more than a hundred and fifty varieties of black walnuts have been named. Yet at the present time we are not certain which are the better varieties except in a very general way. There is no widely accepted judging schedule being used as is evident in the tables published by Seward Berhow in his paper in the 1945 Proceedings (2). In these tables scores are given but these come from several sources and are not comparable and hence are of little value in making comparisons.
There have been many schedules for judging black walnuts presented in the past. One of the first was proposed by the late Willard G. Bixby (3, 4). This was complicated and never came into general use although the testing done by Mr. Bixby was a valuable contribution to our knowledge of varieties. The late N. F. Drake tested many varieties through the years according to a schedule of his own devising (5, 6). Professor Drake's schedule was related to his concept of a perfect walnut and the various values were related to this on a percentage basis. This schedule never had wider acceptance, chiefly because it was too complicated and required too much figuring.
Mr. C. A. Reed has probably tested more varieties of nuts and is more familiar with varieties than any other person but he does not have a definite scoring schedule. Kline and Chase (7) summarized results of the testing work that had been done and Kline (8) compared varieties according to a system which he devised in which they were rated in terms of return per hour of labor spent in cracking and extracting the kernels. Mr. C. C. Lounsberry has proposed a method of scoring which was related to kernel cavity measurement (9).
In 1935, a Committee on Varieties and Standards endeavored to formulate a working schedule that would be adopted as official. This committee set up a score that represented the best thinking of the group at that time (1). Twenty-five nut samples were used. The score was the sum of the weight of an individual nut in grams plus twice the per cent kernel of the weight of the nuts recovered in the first crack plus the total percentage of kernel plus 1/10 of a point for each quarter kernel recovered. Penalties were proposed for shrunken kernels and empty nuts. Through the years a large number of samples have been tested according to this scoring schedule (11). In 1943, MacDaniels and Wilde (12) summarized the previous work done, added many tests and evaluated the scoring system. This was not considered to be altogether satisfactory. In the first place, it was somewhat cumbersome and had never been adopted by the Association nor had it been used much by others. The figuring of percentages and penalties made a score too involved for wide aceptance. A very serious difficulty was the problem of shrunken kernels and empty nuts. Obviously, with a score related to the weight of the sample before cracking, the inclusion of a number of empty nuts made it impossible to make any accurate correction in the percentages that were used in the score. Penalties did not solve the problem. Also the initial weight of the sample varied with the amount of husk clinging to the shells. From this work it was evident that an acceptable score would have to be formulated on some other basis.
The next approach was to analyze data of this type statistically in an attempt to devise a better scoring system (1). The results from such a study proved valuable in answering such questions as 1) the size of sample necessary to obtain significant differences between samples; 2) the significance of small differences in measurements or in scores and 3) the amount of variation that is normal and without significance in comparing varieties.
The following qualifications were considered essential to a workable schedule:
1) The schedule must be easy to use.
2) The schedule must concern itself with objective qualities or characters which can be weighed or measured. It cannot be concerned with flavor and other characters upon which there may be disagreement and which depend upon personal preference.