I_M lock: STUDIES l\ PLANT BREEDING 



offspring of white grains is notably less than among tho off- 

 spring of black grains. In the case of the Latter the total 

 number does not tall far short of 50 percent., which is the pro- 

 portion expected if black is regularly dominant. In the case 

 of the offspring of whites, on the other hand, we musl suppose 

 dominance of black to fail altogether in a considerable pro- 

 port ion of cases. 



3. Offspring of F2, Series 3. | Yellow Dent < White Dent ) x 

 (White Dent < Black Mexican x G. W. S. 



Expt. 15. Offspring of whitt grains. 



8 plants out of 27 showed a certain proportion of black 

 grains; the remainder bore only white grains. ICxpectittion 

 I 7 mil of HI. 



Ex j>t. Hi. Off spring of black grains. 



."•I plants all showed a certain proportion of black grains. 



F4. 



Pollination was again by (•. W. S. throughout. 



1. Offspring of one of the Plants with exclusively Black Grains 



described in Expt. 42. 

 Expi 17. -32 plants were obtained, all of them showing 

 approximately 50 per cent, of black -tains, though in several 

 ol them only a few grains ripened. It would seem, therefore, 

 we have now arrived by selection at a strain in which 

 the black character is practically always dominant.* 

 The four mosl prolific plant- yielded the following grains : - 



Table 21. 



I • 1,163 I'.i l 50-6 



in Journ. Bxp. Zool. LI 



