Genetic Architecture of Grain Quality Traits in Nutrient Rich Rice (Oryza sativa L.) Crosses 

The precise knowledge of the nature of gene action for quality traits in rice helps to choose an effective breeding strategy to accelerate the pace of genetic improvement of quality traits in rice. The Generation mean analysis indicated absence of epistasis in case of certain quality characters like hulling percent, milling percent, kernel length, breadth and kernel elongation ratio in first and second crosses. The interaction was of duplicate epistasis for milling percent and kernel length, therefore, in addition to the main genetic effects, ([d], [h] components), for development of a variety / hybrid from the cross (RP-Bio-5478 -185 x  NH-686), the interaction components also have to be taken into consideration in breeding. Selection was recommended for head rice recovery improvement, for two crosses viz., MTU 1010 x NH-686, WGL-32100 x RP-Bio-5478-166, due to presence of fixable genetic variation. The interaction components are highly variable, therefore, a cross and trait specific breeding strategy is required for quality improvement in three crosses.