IN THE TROPICS : III. 



127 



3.— Offspring of No. 1 of Table 20. 



Expt. 52. — White grains gave rise to 43 plants, 42 of which 

 produced white grains only, whilst one bore a few black grains 

 in addition. This must be taken as showing that the bias 

 shown in Table 20 towards a lower percentage of black grains 

 than 50 per cent, is a real one and not simply fortuitous. In 

 other words plants which show very nearly 50 per cent, of 

 black grains may still be bearing a small number of grains in 

 which dominance of black is wanting. 



Expt. 53. — Black grains gave rise to 50 plants, bearing 

 black and white grains — usually 50 per cent, of the former 

 but in some cases fewer. 



Table 26. 



Plant. 



1 .. 



2 . 



3 . 



4 . 



5 . 



6 . 



7 . 



8 . 



9 . 

 10 . 

 11 



12 . 



Black. 



White. 



Total 2,046 



Excluding 1,553 

 6, 8.11 



2,375 



1.575 



4,421 

 3,128 



46-3 



49-7 



53-7 



50-3 



Discussion of the Results obtained with the 

 Black Character. 



By the examination of F 3 and F 4 it was found that the 

 result of crossing the heterozygote (black x white) with white 

 was not always the same, but that one of two things might 

 happen. In the one case dominance of black was complete, 

 so that the ordinary Mendelian proportion— equality of black 

 and white — was found. In the second case the proportion 

 of black grains was less than 50 per cent, (usually about 30 



9(8)06 (5) 



