162 LOCK : STUDIES IN PLANT BREEDING 



18 of the above plants had red pericarps and 16 white. 



Table 47 shows only the percentages of the two extreme 

 Specimens of the above series and of three intermediate speci- 

 mens (chosen for their large size). 



Table 47. 



Summary of Behaviour of Blue in Mongrel Crosses. 



(1) The offspring of the cross (w x b) x w showed as a 

 general rule less than 50 per cent, of blue grains. It is therefore 

 inferred that the blue character is dominant only in the case 

 of certain grains, namely, those in which the blue colour is 

 visible, whilst white is assumed to be dominant in such a num- 

 ber of the white grains as will make up the expected number 

 of 50 per cent, heterozygotes. The offspring of the white 

 grains was found on examination to confirm this last assump- 

 tion in every case. 



(2) Another notable phenomenon was the sporadic appear- 

 ance of dominance of blue in all those grains of a cob which 

 were expected to bear the blue character, i.e., in all the grains 

 of a cob when these were of the nature (b x b) x w. or in 50 per 

 '•cut . of grains of the nature (b x w) x w. so that in these cases, 



m exception to the more general rule, the Mendelian laws 

 of dominance and segregation were followed in the simplest 

 manner possible. 



In one experiment this appearance of regular dominance was 

 found to be largely inherited, but in another scarcely at all. 



The explanation of this sudden appearance of a regular 

 Mendelian behaviour was not arrived at. Its elucidation 



would Ix a somewhat tedious process, bul by no means an 



impossible one, provided thai all tlic plants examined were 

 fertilized i>,\ hand, so that both male and female parents 



