Correlation and path-coefficient analyses of seed-yield components in pearl millet x elephantgrass hybrids

Correlation and path-coefficient analyses have been successful tools in developing selection criteria. Since increased seed yield is an important goal in our pearl millet x elephantgrass [Pennisetum glaucum (L.) R.Br. x P. purpureum Schum.] hexaploid breeding program, we used correlation and path-coefficient analyses on seed data. This study was conducted to develop appropriate selection criteria by determining the direct and indirect effects of seed-yield components on seed yield plant(-1). Number of tillers plant(-1), panicles tiller(-1), seeds panicle(-1), 100-seed weight, and seed yield plant(-1), were estimated for individual plants in seven families. Phenotypic (rp) and genetic correlations (rg) were calculated, and path analyses (phenotypic and genetic) were carried out according to predetermined causal relationships. Phenotypic and genetic correlations differed in several cases due to large environmental variance and covariance. Phenotypically, all components were positively and significantly associated with seed yield plant(-1). Genotypically, only seeds panicle(-1) and 100-seed weight were significantly correlated. These two components were also positively correlated (r p=0.55, r g=0.63), so simultaneous improvement for both components would be feasible. Panicles tiller(-1) and seeds panicle(-1) were negatively correlated (r g=-0.97). In the path analyses, all direct effects of the components on seed yield plant(-1) were positive. Phenotypic indirect effects were not as important as genetic indirect effects. The components seeds panicle(-1) and 100-seed weight influenced seed yield plant(-1) the greatest, both directly and indirectly.