Received: 10th September 2020; Accepted: 15th November 2020

Abstract

Recombinant Inbred Lines (RILs) derived from crosses between elite cultivars and wild introgression lines are important sources of new genetic variability. In this study 177 RILs derived from a cross of Swarna / 166s (Swarna /Oryza nivara), were characterized for yield and grain shape related traits for two seasons Rabi 2018-19 and Kharif 2019. Phenotypic correlation analysis showed that, single plant yield had a positive association with productive tiller number, total tiller number, panicle weight, biomass and harvest index in both the seasons. Significant and positive correlation was observed between grain length and grain perimeter followed by productive tiller number and total tiller number. A perfect negative linear relationship was observed between filled grain percentage and unfilled grain percentage. Across the seasons, biomass weight consistently showed significant positive correlations with the majority of yield contributing traits, followed by days to 50 percent flowering. Grain shape traits (grain length, grain width, length/width ratio, grain area and grain perimeter) were interrelated with each other significantly. Trait association study in this mapping population showed that though the yield performance has always been the main focus of breeding programmes, the complex interaction of the yield attributes is also equally significant to understand the genetic mechanisms for yield improvement. Selected RILs from this study are being used in rice improvement programmes to detect favorable genes from O. nivara for yield improvement.