130 



The Journal of Heredity 



ratios of the individual ears that are 

 heterozygous are in accord with the 3:1 

 proportion. The total count of thirty- 

 one segregating ears resulted in 4544 

 normal and 1390 defective grains. 

 There w^as a slight deficiency of the 

 latter, which may be due to the diffi- 

 culty of detecting every defective ker- 

 nel on an ear since some of them are 

 very small and may be easily over- 

 looked. It is entirely possible, however, 

 that this consistent deficiency of the 

 defective kernels may be accounted for 

 by differential pollen tube growth. 



However, the best test of the situa- 

 tion is the progeny test, since in this 

 case there is absolutely no difficulty in 

 classifying a normal ear from one that 

 is segregating for the two types of 

 kernels. Such a progeny test appears 

 in Table II. 



There were actually fifteen ears with 

 nothing but normal grains and thirty- 

 one with the two kinds of grains. This 

 is as close to the expected results as 

 possible, and it proves that the defec- 

 tive kernel-type of this Golden Bantam 

 variety is controlled by a simple, Men- 

 delian factor. 



One of the ears of the last season's 

 harvest (5016-11) presented a very no- 

 ticeable deviation from all others. It 

 had a higher proportion of defective 

 kernels than any other ear. Besides 

 112 normal and 44 defective kernels 

 there were 37 kernels that showed a 

 peculiar white appearance (Figure 19). 

 This is especially remarkable since in 

 the three years of inbreeding of this 

 variety, never did any white endosperm 

 occur. These kernels were also of a 

 defective type, but distinctly different 

 from the other. Not only was this new 

 type white in appearance, but there 

 was a marked tendency for the germ 

 to commence growth on the ear. The 

 growth of the embryo consisted mainly 

 of an elongation of the primary root 

 which attained the length of about one- 

 half inch or less within the seed coat. 

 V/hen the grains dried out at maturity 

 the entire embryo turned brown and 

 died. The details of the inheritance of 



this new type (or mutation) are not 

 known as yet. 



Inheritance of the Flint-Defective 

 Type of Endosperm 



Another type of defective kernel 

 arose in some inbred strains of a yellow 

 flint variety, which originally came from 

 Massachusetts. According to Dr. W. 

 E. Castle who sent the original seed 

 to the writer, the variety name was 

 Stickney, being most likely a selection 

 from Longfellow Flint. 



In this case, certain inbred ears ex- 

 hibited a distinct segregation into nor- 

 mal and defective kernels. The latter 

 are distinctly a pale yellow color, con- 

 trasting sharply with the dark yellow 

 color, typical of the variety. This color 

 distinction is enhanced by the difference 

 in endosperm texture. While the nor- 

 mal seeds are characteristically hard 

 and flinty, the defective kernels are 

 dull and starchy in appearance, and 

 somewhat smaller in size (Figure 16). 



The germination of the defective ker- 

 nels is very poor. But the striking 

 thing is that whenever they do germi- 

 nate, they produce white or albino seed- 

 lings. The photograph (Figure 20) of 

 the seedling flat shows the situation 

 very well. When the normal seeds of 

 the segregating ear are planted sepa- 

 rately from the defective kernels, the 

 former produce green seedlings while 

 the latter throw pure whites. The al- 

 ternate rows in the flat show this very 

 distinctly. 



A study of the inheritance of this 

 flint-defective endosperm has been ren- 

 dered very difficult by reason of a large 

 amount of pollen sterility in this inbred 

 strain. Self -pollinated ears are ob- 

 tained only with great difficulty. Cross- 

 bred ears are easily made, showing 

 that the ovules are fertile. 



The original ear (2258-5) showing 

 this abnormal endosperm characteristic 

 was one of a large family that was 

 heterozygous for white and pale yellow 

 seedlings, which were in every way 

 typical of the ordinary seedlings show- 

 ing such chlorophyll defects. This fact 



