Determining cause-effect relationship among yield and yield components in upland rice genotypes

A study was undertaken to evaluate cause effect relationships among quantitative traits in upland rice genotypes in biennial experiment i.e. Kharif 2013 and 2014 of SG College of Agriculture and Research Station, Jagdalpur, Chhattisgarh. A total of 18 local and exotic genotypes were studied under complete rainfed treatment. Analysis of variance revealed significance in all traits indicating presence of considerable amount of genetic variation. In first experimental season (E 01), biological yield per plot had the maximum positive effect (1.0836) on grain yield followed by harvest index (0.8311) and panicle length (0.1176). Positive direct effects of these traits on grain yield indicated their importance in determining this complex character and therefore, should be kept in mind while practicing selection aimed at the improvement of grain yield. In present study (pooled over environments), biological yield has maximum direct effect on grain yield (0.9485) and indirect effect was 0.2200 mainly due to plant height (0.3018), panicles per square meter (0.3071) positively and harvest index negatively (−0.3788). Hence, biological yield should be higher in upland genotypes, which will in turn increase plant height, panicle length.