Linkage studies of awn in cultivated rice (Oryza sativa L.)

Abstract

The inheritance of awn in cultivated rice has been investigated. It was found to segregate inF 2 in three kinds of ratio, namely, 9∶7, 15∶1, and 3∶1, in different cross-combinations. FromF 1,F 2 andF 3 in the cross Chou-chiu-ku x Tze-ta-hei, the awned was found to be due to two complementary factors, and dwarfness to a recessive. One of the awned factors was shown to be linked with the factor for dwarfness with a crossing-over value of 11·38±3·61%, while in the cross Ta-hei x Huang-hsueh-no, a crossing-over value of 22·99±5·20% was found between the awned and dwarf factor. On the average the mean crossing-over value was 17·18±6·33%. In the cross Huang-mu x Hei-chueh-chiu-li-hsiang-keng, theF 1 is awned with black hull, and theF 2 segregated in the ratios 15 awned: 1 awnless and 12 black: 3 while: 1 brown for hull colour. The combined results point to linkage between these two characters, and it was suggested that one of the two duplicate factors for awn was linked with the epistatic factor for black hull colour. The crossing-over value calculated from this assumption is 20·80±4·20%, which fits the observed data very well. The awn factors are inherited independently of leaf-sheath colour, pubescence of hull, pericarp colour, auricle and juncture colour, internode colour, midrib colour, ligule colour, character of endosperm, apiculus colour and empty glume colour.