82 



THE INHERITANCE OF CHARACTERS IN RICE 



All the greens are the same with no difference between heterozygotes and 

 homozygotes. In all the above families the type of golden colouring has been 

 uniform in each family but varying in different famiUes. 



On the presence and absence hypothesis an inhibitory factor must be 

 responsible for the failure to develop golden colouring in the above families. 

 It is possible that the actual production of this colouring is dependent on the 

 presence of a factor which may vary for the different types of colouring. In 

 this case it must be assumed that all these families were pure for one or more 

 such factors. No definite proof of the existence of such factors has so far been 

 obtained but there is some indication of this in certain complicated families 

 in which different types of golden colouring occur together. 



In one such family, which was not giving the ordinary S : 1 ratio, two 

 distinct types of gold were present. The F2 parent, which possessed light 

 golden inner glumes and internode, gave very few plants in Fo. Of these the 

 inner glumes varied from green to dark gold with various intermediates ; a 

 rough analysis showed green 9, light gold 9, dark gold 5. All internodes were 

 golden and this character has been pure in the further generations. Four of 

 these F2 plants gave glume characters in F3 as shown in Table IV. 



Table IV. 



In all plants described as green the glumes were distinctly yellowish as 

 compared with typical greens but they ripened to the ordinary straw 

 colour. 



In No. 431-N the ripening gold group could be distinguished only with 

 difficulty at flowering, but, as the grain developed, the colour became more 

 pronounced till at maturity it was a definite dull gold of a rather light shade. 

 All unset grains remained green whereas in ordinary gold types unset grains 

 are definitely gold though they fail to darken with age. Table V gives the 

 results of a further generation from this family. 



