Correlation, path coefficient analysis and heritability of grain yield components in pearl millet (Pennisetum glaucum (L.) R. Br.) parental lines

Twenty four parental lines of pearl millet A/B pairs developed jointly by Lake Chad Research Institute (LCRI), Maiduguri and International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Kano during 1997 to 1999 were evaluated along with a seed parent (ZATIB) across five locations to determine yield and yield component relationships, heritability estimates as well as genetic advance. Correlation coefficient analysis showed that stand count (r=0.249), plant height (r=0.435) and head weight (r=0.958) significantly (p<0.05) and positively correlated with grain yield while days to 50% flowering significantly but negatively correlated (r=-0.539) with grain yield. There were negative but none significant correlation between grain yield with downy mildew score (r=-0.100) and Striga count (r=-0.095) while downy mildew score and Striga count negatively correlated with stand count (r=-0.155 and r=-0.065 respectively). Head weight has high positive and significant environmental, genotypic and phenotypic correlation coefficient with grain yield (re=0.920; rg=0.900 and rp=0.980). Positive and significant genotypic and phenotypic correlation coefficient exists between plant height and grain yield (rg=0.593 and rp=0.417). Path coefficient analysis indicated that stand count had strong positive direct effect (0.970) on grain yield followed by plant height (0.953). Head weight expressed high negative direct effect (-0.846) on grain yield. The parental lines under study showed high to moderate broad-sense heritability; with panicle length expressing the highest heritability (78.95%), followed by grain yield (75.43%) and head weight (73.30%). The rest characters expressed moderate heritability values. Panicle length and head weight displayed high heritability and high genetic advance indicating that the two traits might be controlled by additive gene effects. This suggests that selection in the segregating generation may be effective. Phenotypic correlation approximates genotypic correlation coefficient in this study, indicating that the influence of environment may be probably minimal and traits with high predictive values can be selected early in the breeding program as against traits with low predictive values.   Key words: Pearl millet, correlation, path analysis, heritability, genetic advance.