Linkage studies in rice (Oryza sativa L.): Flowering, awning and awn colour, panicle density and exsertion, liguleless, bent node and pigmentation

Summary

The cross of two indica types of rice T9 and M35, provided scope for the inheritance study of 16 characters such as flowering, awning and awn colour, panicle density and panicle exsertion, presence of ligule, bent node, and pigmentation in ten other characters. Besides the purple colour, yellow and chalky white were studied for their inheritance. Two to five pairs of factors were found to govern the 16 characters under study. Complementary, duplicate, complementary duplicate, inhibitory complementary and inhibitory duplicate action of genes was observed. Independent dominant action of individual genes which is equivalent to the action of two or three genes is recorded in respect of panicle density and awning and awn colour. Inheritance of the 16 characters shows the involvement of 59 genes unreported in the past. Out of them 19 are inhibitors. Combined segregation data have revaled the existence of many pleiotropic genes acting on two or more characters and exhibiting differential expression in some of them, which is an interesting part of the present study. Linkage analysis has resulted in the assignment of the record number of 17 genes to a single group, nine of them being inhibitors. The linkage map constructed in the order of genes as suggested by the cross over values shows a good agreement. This linkage group is concluded not to form part of any group propounded by Misro et al. (1966) in indica rice.