264 D. F. JONES. 



to be a hybrid as all the ears were segregating for yellow and 

 white sweet seeds. It therefore had certainly been crossed with 

 a white sweet inbred strain the year before as other pollinations 

 of this sort were made at that time. The yellow color of the 

 endosperm was not sufficiently diluted to cause the seed to be 

 suspicioned before planting. 



Since the plants were segregating for yellow and white it was 

 not material which would have been used ordinarily for mixing 

 with a white starchy strain. The effects of the starchy-carrying 

 pollen showed up all right among the all sweet seeds but the 

 reciprocal cross-pollination showed only the yellow cross-fertilized 

 seeds. The white cross-fertilized seeds of course could not be 

 distinguished from the self-fertilized seeds. But since half of the 

 pollen grains carried yellow and half of them white the number 

 of yellow seeds can be doubled to give the total number of cross- 

 pollinated seeds and the assumed number of white cross-fertilized 

 seeds subtracted from the white seeds. This increases the error 

 from random sampling somewhat but since the number of yellow 

 seeds is very low in comparison with the white in these mixtures, 

 the data are reliable in view of the great selective action shown in 

 these two mixtures. The fact that the yellow color in this 

 material was a unit factor difference and that there were equal 

 number of pollen grains carrying yellow and white is proven by 

 the self-fertilized ears produced by the hybrid which gave very 

 good 3 to i ratios (one ear counted gave 318 yellow and 97 white 

 seeds). Furthermore the starchy crossed seeds produced on the 

 hybrid plants were of two kinds, yellow and white, and were 

 produced in equal numbers (actual numbers: 28 yellow and 27 

 white. Since the ovules were segregating equally and the self- 

 fertilized seeds gave the mono-hybrid ratio the pollen grains 

 must have carried the two colors in equal amount. 



In the last four mixtures the characters, purple sweet and white 

 starchy, were used. In numbers 17 and 18 the plants were not 

 producitve and the numbers of seeds are low. Also the classifica- 

 tion of purple starchy cross-fertilized seeds and white starchy 

 self-fertilized was not as sure as in the other mixtures. In the 

 last two mixtures satisfactory numbers were obtained and the 

 differentiation was clear-cut on both sides. 



