Path Coefficient-Based Identification of Strategic Selection Targets for Yield and Grain Quality Improvement in Rice

Abstract

Rice (Oryza sativa L.) is one of the most important staple food crops worldwide, and improvement of
grain yield along with nutritional quality is a major objective in rice breeding programmes. The present
investigation was undertaken to estimate the direct and indirect effects of yield contributing and grain
quality traits on grain yield in the rice cross Rpbio-226 × Jalmagna through path coefficient analysis. Six
generations namely P₁, P₂, F₁, F₂, BC₁ and BC₂ were developed and evaluated during kharif 2012 under
irrigated conditions at the Directorate of Rice Research (DRR), Hyderabad. Observations were recorded
for plant height, days to 50% flowering, panicle length, productive tillers per plant, filled grains per
panicle, test weight, kernel dimensions, grain iron content, grain zinc content and grain yield per plant.
Path coefficient analysis revealed that productive tillers per plant exhibited the highest positive direct
effect on grain yield followed by filled grains per panicle, L/B ratio, kernel breadth and plant height,
indicating their importance as major selection criteria for yield improvement. In contrast, days to 50%
flowering, panicle length, test weight, kernel length, iron content and zinc content showed negative direct
effects on yield. The residual effect (0.4134) indicated that the studied traits contributed substantially
toward yield variation. The results suggest that emphasis on productive tillers per plant and filled grains
per panicle would be effective for identifying superior high yielding segregants with desirable grain
quality traits in rice breeding programmes.