166 ANTHOCYANINS AND GENETICS 



Leake (561) worked with Indian cotton. Four varieties connected 

 with anthocyanin pigmentation were used, i.e. 



1. A variety in which the petal is entirely red having a darker 

 spot at the .base. 



2. A variety in which the petal is yellow with a deep red spot 

 at the base. 



3. A variety in which the petal is pale yellow with a basal spot. 



4. A variety in which the petal is white with a basal spot. 

 Leake identifies the following factors. A factor for yellow which is 



dominant to white, and a factor for red which is dominant to white and 

 yellow. Individuals heterozygous for the reddening factor have petals 

 only partially coloured ; this is very obvious in red on yellow, but less so 

 when on white. A scheme of the factors may be represented as : 



YRr red on yellow. 



YRR red. 



RR(r) red on white. 



Y yellow. 



white. 



In some of the strains used there was also anthocyanin in the vege- 

 tative parts, that is in the young leaves, and in the ribs and veins of 

 the mature leaf; in other strains, these were quite green. In the Fj 

 from a cross between these red-foliaged and green-foliaged strains, the 

 red colour was dominant, though diminished in amount. In F 2 there 

 was segregation into red and green in the proportion 3:1. Among 

 the individuals with red colour there was a considerable range in 

 intensity, though the DD individuals had more pigment in the leaf 

 than the DR, and by this means they could be separated with a fair 

 degree of certainty. There is an association also between anthocyanin 

 in the vegetative parts and the complete redness of the flowers. 



Helianthus. Shull (520) has made some experiments with this 

 genus. The wild Helianthus annuus of the Prairie region has a purple 

 disk, the colour being found in the tips of the paleae which are a deep 

 metallic purple, the margin of the corolla which is brownish-purple 

 and the style and stigmas which are reddish-purple. The 'Russian 

 Sunflower' (Helianthus annuus, var.) has the tips of the paleae yellowish- 

 green, the corolla a clear lemon yellow, and the styles and stigmas 

 usually have the same colour as the corolla. Shull concluded, on the 

 results of crossing, that the purple disk is a strict Mendelian character 

 and is dominant to the yellow disk. 



The red sunflower mentioned by Cockerell (602, 603, 611) appears 



