TABLE 6
Tests and Scores of Black Walnut Varieties from Various Sources.
25 nut samples unless otherwise indicated.
All scores figured on basis of 25 nuts.
- D—Dry
- S—Soaked
- No.—Hours dried or soaked
DISCUSSION
In the light of the data presented some conclusions can be drawn on the various questions raised at the beginning of this paper. It is evident that if approximately the same score is to be obtained by one operator on duplicate or replicate random samples, great care must be used in sampling. There is a tendency in taking samples to pick out the larger nuts or in some other way fail to take a good random sample. Selections submitted for contests are likely to be quite misleading as to the value of the variety and reflect in considerable part the contestant's skill in selection rather than the merit of the clone. The Freel walnut seems to be an example of this. At least as grown at Ithaca it is very disappointing.
It is evident that if comparable scores are to be obtained the samples receive the same treatment particularly as regards moisture content. Samples should be dried sufficiently to show the shrinkage of poorly developed kernels but in no case be allowed to dry to the point of checking the shells. Uniform soaking practice is a step in the right direction. A green or partially dried nut will test much higher than one properly cured as evidenced by Snyder, sample 6 and Spear, sample 7 in Table 1.
It seems probable that no schedule can be devised that will eliminate the necessity for skill on the part of the operator. To obtain satisfactory uniformity in scores, it is essential that the operator be skilled in the use of the cracking machine and use continuous care in applying the necessary pressure and in holding the nut in the anvils. Undercracking or overcracking, reversing the ends of the nut in the anvil or failure to hold the nut vertical may affect the score.
The presence of empty or poorly filled nuts in a lot of nuts from which samples are taken at random introduces greater variability in the samples than that found in lots with all nuts filled. This is true because the chances of getting an equal number of empty nuts in 25 nut samples are small and the presence of each empty nut decreases the per cent kernel and also the numbers of quarters possible. Variations due to empty nuts could be eliminated by greatly increasing the number of nuts in the sample but this is not practical for the purposes this schedule is intended to serve.
The question of whether or not it is possible for different operators to obtain equal scores on duplicate samples is not satisfactorily answered by the data in table 4. As the data stand the scores are far from equal. There is, however, a consistency in the scoring of each operator and it is quite probable that with more uniform treatment of nuts before cracking and more careful sampling better agreement would be achieved. This is borne out in the data given in table 5 in which the variation in scores between the two operators was no greater than that obtained by the same operator.