Optimization of priming time and concentration of bioprimers and their influence on bajra seed

A series of experiments were carried out to optimize the suitable concentration and duration of seed bioprimers like Azotobacter chroococcum and Azospirillum lipoferum to improve seed germination and seedling vigour. The seeds bioprimed with A chroococcum Azo 311 cells (T₁-T₅) enhanced germination by 30–35 per cent over control. High concentrations of A lipoferum Azs 301 (T₈, T₉, T₁₀) significantly enhanced germination by 30 per cent over control. Pennisetum seeds primed for 30 min with biofertilizers ranging from 0.8–4.8 x 10⁶ colony forming units (CFUs)/seed increased germination by 30–35 per cent over non-primed seeds and reduced radical emergence time RT50 by 24 h. Highest root length was registered in seeds primed with A chroococcum Azo 311 by 66 per cent followed by A lipoferum Azs 301 inoculation by 60 per cent and Bradyrhizobium sp Rbg 314 by 33 per cent over control. Twenty four hours of contact with A lipoferum Azs 301 significantly increased shoot length by 28.5 per cent while A chroococcum Azo 311 priming enhanced shoot length by 33.3 per cent over control. The results revealed that seed biopriming along with recommended dose of nitrogen fertilizer (24 kg) yielded the best vegetative growth in terms of root and shoot length and weight over non-primed seeds.