Trait selection by path and principal component analysis in Jatropha curcas for enhanced oil yield

• Path analysis helps to determine the nature of relationship between yield and other characters.
• Principal components analysis assesses major contribution of variables to total variation.
• Identification of important characters directly or indirectly related to oil productivity.
• Selected traits may serve as criteria for oil yield improvement and further recurrent selection.
• Identification of diverse germplasm with distinct traits to be employed as parents for breeding.

Path analysis was done on different morphological, physiological and oil quality traits of 15, six-years old candidate plus trees of Jatropha curcas to assess their direct and indirect effect on oil yield. Principal component analysis was subsequently done to assess the pattern of the variations in characters and segregate the traits to distinguish parental accessions for plant improvement. Total chlorophyll had a positive direct effect on oil yield and also had indirect effect through single seed weight, single fruit weight and oil content. Male to female flower ratio had negligible direct effect on oil yield but had considerable indirect effect through seed yield per plant. Seed weight, fruit weight and seed yield plant−1 had a high direct effect on oil yield and also had indirect effect through oil content and thus found suitable for direct selection. The first five principal components contributed 75.5% of the total variability. The accessions JCN14, JCN08 and JCN09 had very high values for the first component, while JCN04 and JCN05 had lower values for all these variables.