International Journal of Plant & Soil Science

This investigation was carried out at International Institute of Tropical Agriculture IITA, Ibadan, Nigeria to estimate correlation coefficients of yield and associated traits of thirty-six upland rice lines and the effect of these attributes in four weeding regimes. The weeding regimes were: weed free, weeding twice (21 and 42 days after sowing (DAS), weeding once at 42 DAS only, and weeding once at 21 DAS only, laid out in an alpha lattice design replicated two times. Correlation analysis indicated that yield was significantly and positively associated with panicle length, panicle number and 100 seed weight in both years. There was also a highly significant negative correlation between weed dry matter at all the sampling periods and number of tillers, plant height at maturity in 2011 and number of panicles and panicle length in 2012. Weed dry matter was negatively correlated with grain yield (P < 0.01) in both years clearly explaining the adverse effect of weed on the yield of rice. Path analysis revealed that days to 50% flowering, 100 seed weight, number of panicles and panicle length had direct positive effect on yield across the weeding regimes. Hence, selection based on these traits could help bring simultaneous improvement of yield and yield attributes. For further breeding activities, more emphasis should be given to 100 seed weight, days to 50% flowering, number of panicles and panicle length as they showed high correlation in addition to maximum direct positive effects on yield.