Nutritive value of canola (Brassica napus L.) as affected by plant growth promoting rhizobacteria

Comparative evaluation of plant growth promoting rhizobacteria viz. Azospirillum brasilense, Azotobacter vinelandii Khsr1 and chemical fertilizers was made on growth, protein, and oil yield as well as quality of canola (Brassica napus L.) cv. Rainbow. The A. brasilense and A. vinelandii were applied as seed inoculation at 10⁶ cells/mL. The recommended doses of urea (150 kg/ha) and diamonium phosphate (180 kg/ha) were applied as sources of chemical fertilizers. First dose of chemical fertilizers was applied at the time of sowing while other three doses were applied at 45 days interval. The chemical fertilizers were highly effective in increasing leaf chlorophyll content, number of branches per plant, number of siliqua per branch, number of seeds per siliqua, and total seed yield. A. brasilense treatment increased the leaf and seed protein content (32 and 21%) as well as seed size as measured by % increase in 1000 seed weight. A. vinelandii treatment resulted in significant increase (4%) in seed oil contents but the glucosinolate and erucic acid (C22:1) contents of oil was decreased significantly. Maximum oleic acid (C18:1) content was found in seed oil of A. vinelandii treatment; whereas, significantly higher linolenic acid (C18:3) content was recorded in A. brasilense treatment. It is inferred from the present investigation that A. brasilense and A. vinelandii could be highly effective in improving yield and nutritive value of canola oil.