Standardization of Azospirillum concentration and duration of biopriming for rice seed vigour improvement

Azospirillum lipoferum is nitrogen fixing biofertilizer which can be used in seed treatment for improving seedling vigour. In order to standardize the optimum concentration of liquid Azospirillum for rice biopriming seed treatment and duration of biopriming, a laboratory experiment was conducted in Department of Seed Science and Technology, Tamil Nadu Agricultural University, Coimbatore in CompletelyRandomizedDesign with four replicates. Rice hybrid CORH 4 and its parental lines COMS 23A and CB 174R seeds were bioprimed separately with 10, 15 and 20 per cent of Azospirillum for 6, 12, 18 and 24h of durations. Unprimed and hydroprimed seeds were used as control. The result revealed that rice seeds bioprimed with 20 per cent Azospirillum for 12 h was found to be the best seed biopriming treatment for both CORH 4 rice hybrid and its parental lines to enhance the germination rate, total germination percentage, seedling growth and vigour. In rice hybrid CORH 4, biopriming with 20 per cent liquid Azospirillum for 12h expressed an increase of 14 per cent of vigour index over the non-primed control seeds.