The occurrence and inheritance of purple-tipped grains in sorghum

Abstract

Almost all grain sorghums are without a purple spot on the top of their grains. In these, the tip of the grain has merely the brownish scar left by the dried stylar base. In some varieties of Kafir the stylar scar is surrounded by a small purple spot. In African Kafirs this purple spot is either feeble or latent. In some Kafirs from America the spot is patent. In crosses with varieties with no purple-tip on the grain the purple tipped grain behaves as a simple Mendelian dominant to the common tipless condition. The gene responsible for this purple-tip on the top of the grain has been designated PGT. In the presence of 'Q' factor this spot is reddish purple. With 'q' it is blackish purple. The purple on the tip of the grain belongs to the same series as the leaf-sheath purple, and the glume purple that goes with it. This factor is independent of the factor 'W' which determines the manifestation of pericarp colour in wholeness. The presence of this dominant colour character in the African Kafir and its disappearance in other cultivated sorghum throws light on the origin and distribution of many of the cultivated sorghums.