Growth promotion of rice seedlings by fungal and bacterial bioagents effective against bacterial leaf blight of rice

In the present investigation, fungal and bacterial bioagents which were effective against pathogen of bacterial leaf blight disease of rice (Xanthomonas oryzae pv. oryzae) was tested for their effect on germination of rice seeds and growth of nursery seedlings under laboratory and glasshouse conditions. Two isolates of fluorescent pseudomonas isolated from rice phylloplane (Pf 83 and FLP 88), Trichoderma species were isolated from soil of rice field (isolate 40) and Trichoderma harzianum isolated from rice phylloplane. Two commercial formulations (PBA-1 and PBA-2) were tested in the present investigation and compared with chemical treatment (0.76 g Emison + 0.18 g Streptocycline / kg seeds) and untreated check. Under laboratory conditions, chemical treatment was found most effective in increasing seed germination (43.90%) followed by Pf 83 and PBA-1 (34.15 %). Bioagent formulations were significantly effective in increase in root and shoot length as compared to check and chemical treatment. Under glasshouse conditions, maximum increase (29.42%) in seedlings emergence was exhibited by chemical treatment. Maximum increase in root length (100.15%) and shoot length (50.06%) was recorded with FLP 88 and T. harzianum, respectively. Bioagent formulations also increased fresh and dry root weight over check and chemical treatment. All bioagents formulations were effective over chemical treatment and check in increasing fresh shoot weight. Results of the present study revealed that in the absence of pathogen of bacterial leaf blight of rice, fungal and bacterial bioagents significantly enhanced germination of rice seeds and growth of nursery seedlings.