HOWARD AND HOWARD. 23 



the crosses in which a pure line of American Club was one of the 

 parents. It will be observed in the figures relating to these ratios 

 that eighteen plants belonging to three crosses were grown in the F 2 , 

 that the mean ratio of red to white was 56'4 to 1, and the total 

 number of plants involved was 2,934. Taking the progeny of the 

 F, plants separately it will be seen the ratios varied between 11 '5 to 1 

 and 179 : 1, while in one culture all the 147 plants had red grain. 

 The greatest number of plants in any one culture was 216 and the 

 smallest number 75. Compared with these the following figures 

 obtained by Nilsson-Ehle in a similar case are of interest : — 



0315 white x Swedish felted red (a) F._, 78 red white. 



(b) „ 30 ,. „ 



(c) •• 49 „ „ 



(d) ,. 31 ,. ii ,. 



(e) „ 86 „ „ 



(f) „ no „ „ 



Investigation of the third generation showed that in reality three 

 red factors were present in the red parent and the F 2 should have 

 given a ratio of 63 : 1 instead of all red plants. The Pusa numbers 

 are undoubtedly better than those quoted from Svalof, nevertheless 

 it was a mistake to grow only some 200 or so individuals from each 

 Fj plant. It would have been better to have made a corresponding 

 reduction in the total number of F, parents. 



In the case of some of the crosses with Punjab Type 9, 'which 

 gave the 15 : 1 ratio in the F 2 , the cultures have been carried on to 

 the third generation and the two red factors isolated. (The crosses 

 in which the 3 : 1 and 63 : 1 ratios were obtained are now being 

 grown in the third generation.) On examining the grain of a 

 large number of the F 2 plants which exhibited the 15 : 1 ratio it was 

 observed that they formed a series and that those with red grain 

 varied in colour from a very light yellowish red to tones as dark as 

 the parent. A similar state of affairs to that observed in the felted 

 chaff of these crosses was therefore obtained, but with the difference 

 that no morphological characters corresponding to the two sets of 

 hairs were present to assist in the unravelling of the series. 



A large number of F a plants, representative of all the various 

 tones of red in the series, were then sown singly seed by seed and the 



