Seed biofortification with Azospirillum spp. for improvement of seedling vigour and productivity in rice (Oryza sativa L.)

Seeds of two vigour lots of rice cv. ASD 18, viz; high vigour (stored for t hree weeks) and low vigour (stored for 56 weeks under ambient conditions) w ere treated with mixed cultures of Azospirillum lipoferum and Azospirillum brasilense, a diazotrophic bacteria, to determine the efficacy on seedling vigour and productivity. Seed treatment with Azospirillum, increased the am ylase activity, during germination. The enzyme level was more in high vigou r seeds. Secretion of gibberellins by the bacterium may be the reason for t his increase and subsequent hydrolysis, resulting in enhanced seedling vigo ur encompassing speed of germination, seedling length and dry weight. The p ositive effect of Azospirillum seed treatment observed on seedling vigour i n the nursery has not improved the yield parameters significantly. The adva ntage observed on seedling vigour may enable the seeds to overcome stresses and can be recommended as a pre-sowing treatment.