98 



THE INHEBITANCE OF CHAEACTERS IN RICE 



aj)pearance. The change takes place so rapidly that it is common to find 

 faded smoky grains at the tips of the panicle before the lowest grains have 

 developed the colour. 



Plate III, figs. 1 and 2, show grains ripening hlach com^^ared with others, 

 from the same segregating family, ripening to the ordinary straw colour. 



The results obtained show considerable comj)lication and are not yet 

 fully worked out. There is no doubt that two factors are concerned in the 

 production of the black pigment and that segregating families may show 

 black : straw ratios oi 3 : 1 oi 9 : 7 according as the parent is heterozygous for 

 one or both of these factors. 



Table XVII shows both ratios appearing in a group of F4 famihes derived 

 from an F3 giving a, 9 : 7 ratio. 



Table XVII. 



There is little doubt that Nos. 813-N and 817-N represent 3 : 1 ratios, 

 though the former is not a very near approximation, and that the other families 

 represent 9 : 7 ratios. 



The above families were pure for the absence of j)urple-lined interuodes. 

 The)' were segregating for a purple pigmentation factor which, hoAvever, did 

 not aflect the segregation for ripening black. In certain families, on the other 

 hand, which were also segregating for purple lining in the internode, there was 

 clear indication of gametic reduplication. It was not until much material had 

 been destroyed, after making simple counts of black and straw, that this 

 reduplication was noted, hence the internode character was not determined 

 in many cases. 



Table XVIII gives the figures for certain families segregating for purple 

 lining in addition to one of the ripening black factors. 



