Correlation and Path Coefficient Analyses of Seed Yield and its Contributing Traits in Cajanus cajan (L.) Millsp

Aims: It is utmost desire for plant breeders to know the extent of relationship between yield and its various components, which will inevitably facilitate selection of desirable characteristics. This research focused on computing the correlation coefficients and path coefficients of yield and its contributing traits in pigeon pea landraces Cajanus cajan (L.) Millsp.
Methods: Seeds of two varieties of locally grown pigeon pea were sown in a randomized complete block design (RCBD) in ten replications. The field study was done at the University of Calabar Experimental Farm, University of Calabar, Calabar, South-South, Nigeria, during the 2009-2010 growing season. Correlation coefficients and path coefficients (partitioned into direct and indirect effects) were estimated on yield and its contributing traits.
Results: Correlation results revealed that there was significant positive correlations between plant height plant-1 and number of leaves plant-1 (0.926**), leaf area plant-1 (0.574*) and number of seeds plant-1(0.616*). It also showed that the number of leaves plant-1 was positively correlated with the pod length plant-1 (0.589*) and number of seeds plant-1 (0.682*). Leaf area plant-1 had a positive significant association with the number of seeds plant-1 (0.581*). Additionally, pod length plant-1 correlated positively with the number of seed plant-1 (0.850**) while number of nodules plant-1 correlated positively with 100-seed weight (0.804**). Path coefficient results showed that 100-seed weight had the highest direct effect on yield (0.583), which was positive. This was followed by the pod length plant-1 (0.519), number of leaves (0.452), and leaf area (0.252) while plant height plant-1 had negative direct effect but very high (-0.633). Number of pod plant-1 had the lowest direct effect on yield (0.033). Additionally, genotypic correlation coefficient with yield showed very high coefficients, especially for pod length plant-1 (0.827), 100-seed weight (0.798), number of leaves plant-1 (0.644), plant height plant-1 (0.582) and leaf area plant-1 (0.549), respectively. Number of nodules plant-1 had the lowest genotypic correlation coefficient (0.042) followed by number of flowers plant-1 (-0.063).
Conclusion: The two results from correlation and path coefficient analyses strongly suggest that plant height plant-1, number of leaves plant-1, leaf area plant-1 and pod length plant-1 and 100- seed weight should be considered as indices for selecting high yielding pigeon pea genotypes, especially the landraces.