324 
LOCK : STUDIES 
PLANT BREEDING 
Weldon found that the figures obtained by Mendel in his 
experiments were such as might fully be expected if the 
theoretical explanation which that author gave to them is 
correct. Weldon was able to select front a sample of the 
pea Telephone (Carter’s) seeds which exhibited a complete 
range of colour from green to yellow, and of shape from 
wrinkled to smooth, and he states that if Mendel had used 
this pea his experiments would have failed. But Mendel 
himself particularly noted the difficulty as regards colour, 
and evidently did use a pea which behaved nearly like 
Telephone in this respect. I have repeated some of Mendel’s 
experiments using Telephone* as the wrinkled green 
parent, and obtained a result closely in accordance with 
Mendel’s own. Gregory (39) has shown, moreover, that in 
cases where a “ round ” and a “ wrinkled ” pea are diffi¬ 
cult to distinguish by the external appearance, a glance at 
the starch grains as seen in a section of the cotyledon 
enables one to place the seed in its proper group at once. 
Bateson (2) in defence of Mendel pointed out that the 
phenomenon of dominance is of quite subsidiary importance 
to that of the segregation of characters in the gametes. He 
showed that exceptions to dominance may occur in the 
categories which Mendel used, but that they have not been 
observed in a large enough number of cases to affect the 
main result. Various explanations may be offered of such 
exceptions, and they still need further study. Very many of 
them are doubtless simply due to error. Bateson pointed 
out the clear agreement with Mendel’s theory of several 
independent observations cited by Weldon as exceptional. 
Yule (79) has pointed out that the law of ancestral here¬ 
dity (in a wide sense as he himself defines it) will hold good 
for the dominant character in a population breeding at 
random and following Mendel’s Law for the particular pair 
* * IOm Sa “ on; but lowing the same phenomenon. My origin*! 
tto P h at yearS ° ld ’ ™ olTldes a We majority of fully yellow seed* 
