The Role of Plant Growth Promoting Rhizobacteria on Oil Yield and Biodiesel Production of Canola (Brassica napus L.)

The aim of the present investigation was to compare the effects of chemical fertilizers and plant growth promoting rhizobacteria viz. Azospirillum and Azotobacter on seed yield, oil content, and oil quality of canola (Brassica napus L.) var. Pakola pertaining to biodiesel production. Azospirillum and Azotobacter were applied as broth culture prior to sowing, while chemical fertilizers viz. urea and Diamonium phosphate were applied @ 185 Kg/hec and 160 Kg/hec, respectively. The first dose of chemical fertilizers was applied at the time of sowing, while another three doses were applied at 40 day intervals. Chemical fertilizers significantly increased number of branches plant(-1), number of siliqua branch(-1), number of seeds siliqua(-1), and total seed yield. However, significant increase in 1,000 seed weight was observed in Azospirillum treatment. Maximum increase in seed oil content was recorded in Azotobacter treatment. Chemical fertilizers and Azospirillum significantly increased seed protein content and decreased oil acid value and free fatty acid (%FFAs) content as compared to the control. Significantly lower glucosinolate and moisture content were recorded in Azotobacter treatment. Significantly higher oleic acid (C18:1) content was observed in Azospirillum treatment. Maximum alpha linolenic acid (C18:3) content was found in Azotobacter treatment. Azospirillum significantly decreased the erucic acid (cis-13-docosenoic acid, C22:1) content. The oil extracted from seeds of chemical fertilizers and Azospirillum-treated plants exhibited maximum (93 and 92%, respectively) conversion to methyl esters as a result of transesterification reaction.