Minimal descriptors for characterization and evaluation of Jatropha curcas L. germplasm for utilization in crop improvement

Jatropha curcas germplasm collected from peninsular region of India as well as germplasm augmented from various parts of the country was characterized for various agro-morphological traits at 3 locations for 3 years. Variability was evident for 38 traits which included both qualitative and quantitative traits. Important yield influencing traits such as plant canopy, branching habit, number of primary branches, peduncle branching, peduncle length, inflorescence compactness, flower ratio, inflorescence abundance, flowering, fruits per cluster, 100-seed weight and oil content showed a wide range of variability in the germplasm under study. Number of leaf lobes also showed variation and accordingly were categorised as 0–2, 3–5, >6. The branching pattern varied widely and has been categorised as basal, intermediate, top and entire. The male to female flower ratio ranged from 10:1 to >20:1, and was categorized into three categories as 10:1, 11–20:1 and >20:1. The seed oil content which is of commercial importance in J. curcas also exhibited wide variability ranging from 17.5 to 41.6% and the descriptor has been categorized accordingly as 0–20, 21–30, 30–40 and ≥40%. Based on the variability observed in the traits, a set of 38 minimal descriptors has been suggested for characterization and evaluation of Jatropha.

► Reports indicate existence of limited genetic variability in Jatropha curcas.
► A first attempt at developing the descriptors and descriptor states for J. curcas.
► A resource guide in germplasm augmentation, characterization and utilization.
► The methodical documentation of diversity enhances the utilization of the germplasm.