Variability Studies on Seed Parameters, Oil and Azadirachtin Content of Neem (Azadirachta indica A.Juss.) in Tamil Nadu and Karnataka

Abstract

Thirty four Plus Trees (PTs) of Azadirachta indica were screened based on the tree morphol. and biochem. traits to identify the suitable source for high oil and azadirachtin contents in order to establish large scale industrial plantations. Significant was observed among 34 PTs for seed and biochem. traits. Maximum 100-seed weight (30.00g) and 100 kernel weight (12.00g) were recorded in NPT 7, while NPT 34 showed maximum oil content (42.81%) and maximum azadirachtin content was documented in NPT 11 (0.972%) followed by NPT 17 (0.970%). High heritability (broad sense) and genetic gain were observed for all seed and biochem. traits resp. Seed weight and kernel weight showed significant correlation with azadirachtin content. Among thirty four PTs, NPT 11, NPT 22, NPT 17, NPT 4 and NPT 29 were found superior in terms of oil and azadirachtin contents. Hence these seed and biochem. parameters could be considered as selection criteria for early and pos. exploitation of high oil and azadirachtin yielding genotypes. Study confirmed that the existence of substantial genetic variation which can be utilized for genetic resource conservation in gene bank and further tree improvement programs.