PARNELL, RANGASWAMI AYYANGAR, AND RAMIAH 85 



It begins to appear at about flowering time, increases in intensity as the grain 

 develops, and then fades to a dull brown during the later stages of ripening. 



It was at first thought that an inhibitory factor, similar to that described 

 fjr golden colouring, existed lor this character also. Numerous figures were 

 obtained showing a, 3 : 1 ratio of yreen to darh furrows. It now appears likely 

 that the greens were not in reality entirely green but that the colour was 

 limited by the piebald factor described below. 



Since the action of this factor was noted all families apparently 

 segregating into greens and dark furrows have been examined carefully and in 

 every case the greens have proved to be in reality piebald dark furrows. It is 

 recorded for some of the earlier lots that the greens were not entirely devoid 

 of colouring and these no doubt were really piebalds. It is not certain, 

 however, that this was true in all cases. 



Many varieties exist in which the glumes are entirely free from this colour- 

 ing, but whether this is due to the absence of the determining factor or to the 

 presence of an inhibitory factor remains to be seen from future work. 



{d) Piebald pattern of golden colouring and dark furrows of 



INNER glumes. 



There is a definite locaKzation factor which affects the distribution of both 

 ordinary golden colouring and dark furrows of the inner glumes. This was first 

 noted in golden types where the colour is inhibited at the base of the glumes, 

 typically to about one-third of the length, and also in a small area at the apex. 

 There is often considerable variation, even in grains on the same head, but 

 the character on the whole gives the very definite piebald appearance of the 

 grain which is common in many varieties (Plate I, fig. 5 and Plate II, fig. 7). 



Reference has already been made to this factor in connexion with dark 

 furrows. Here the effect is extremely irregular in segregating families and 

 even in varieties pure for this character considerable variation exists. The 

 minimum of inhibition corresponds roughly with typical gold piebald (Plate I, 

 figs. Sand 6 and Plate II, figs. Sand 7). This amount of colouring is generally 

 seen in occasional plants only and, even there, is often confined to a few of the 

 upper grains in the panicle. From this all stages may be found down to those 

 iij which a careful search reveals, on a whole plant, only a few grains in which 

 a few specks of colour are present. An ordinary typical piebald dark furrows 

 plant exhibits about the amount of colouring shown in Plate II, tig. 6, on a 

 number of grains in each panicle. 



The piebald character is dominant to self-colour, giving the ordinary 3 : 1 

 ratio in Fj {see Table VII). It has not yet been ascertained whether the 



