44 



LOCK : STUDIES IN PLANT BREEDING 



could be distinguished as being of a decidedly deeper yellow 

 tint than sixty of the remainder. So that in not more than 10 

 per cent, of cases was it doubtful whether a particular yellow 

 grain was a homozygote or a heterozygote. 



Having obtained the proportion 3 yellow to 1 white as the 

 result of mutual pollination between heterozygote plants, and 

 knowing as we do that the female germ cells of similar plants 

 carry the yellow and white characters in equal numbers, we 

 may infer at once that these allelomorphs segregate in the 

 male germ cells in the same proportion. As a further and con- 

 clusive piece of evidence, a white strain (indented) was sub- 

 jected to pollination from the plants enumerated in Table 34, 

 with the following result (Expt. 61) : — 



Table 35. 



Total 



2,723 



2,846 



5,569 



48-0 



Expectation : 50 per cent. 



There is once more a slight excess of white grains over the 

 expected number, and it has to be noted that any accidental 

 escape of pollen from these plants would tend in this direction. 



2. EXPERIMENTS IN WHICH THE BLUE CHARACTER WA8 



CONCERNED. 



Expt. 62. It has been already stated that F i derived from 

 the white grains ofoob No. 1 (P) produced 5 per cent, or less 

 of blue grains. A number of these blue grains were grown 

 upon tli<- same plot as the F 2 from the corresponding yellow 



