Int.J.Curr.Microbiol.App.Sci (2019) 8(5): 339-346 339 Original Research Article https://doi.org/10.20546/ijcmas.2019.805.040 Variability Studies on Seed Parameters, Oil and Azadirachtin Content of Neem (Azadirachta indica A.Juss.) in Tamil Nadu and Karnataka P. Prabakaran 1* , K. Kumaran 1 , L.K. Baburaj 2 , S. Balaji 2 , S. Mageshram 2 , C. Balakumar 2 and R. Radhakrishnan 2 1 Department of Forest Biology and Tree Improvement, Forest College and Research Institute, Tamil Nadu Agricultural University, Mettupalayam 641301, India 2 Bioproducts Division, Coromandel International Limited, Chennai, India *Corresponding author ABSTRACT Introduction Azadirachta indica A. Juss commonly known as neem belongs to family Meliaceae and is one of the important fast growing multipurpose tree species of Indian sub- continent since antiquity. The tree is widely adapted to various climate and soil types. It is commonly found in South Asia and parts of Africa. In India, neem tree occurs in tropical dry deciduous and thorny forests up to an altitude of 1500m. It is a fast growing, hardy, evergreen tree but under extreme conditions, such as extended dry periods, leaf may shed (Tiwari, 1992). It tolerates high temperatures, low rainfall, long spells of drought and salinity. Neem is propagated mainly through seeds. Four to six months old seedlings are ready to plant in the field. Fruiting begins in 4-5 years. In India neem flowers from March to May and fruits mature from June to August. International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 05 (2019) Journal homepage: http://www.ijcmas.com Thirty four Plus Trees (PTs) of Azadirachta indica were screened based on the tree morphology and biochemical 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 biochemical 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 biochemical traits respectively. 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 biochemical parameters could be considered as selection criteria for early and positive 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 programmes. Keywords Plus Trees, Oil, Azadirachtin and Industrial plantation Accepted: 04 April 2019 Available Online: 10 May 2019 Article Info