A field experiment was conducted in a randomized block design, with three replications in a plot size of 1.5 m long six rows spaced 25 cm apart from each other for each treatment in each replication, to investigate the effect of inoculation of Plant Growth Promoting Rhizobacteria (PGPR)—two strains of Azotobacter spp. and one Gluconacetobacter spp.— having antifungal activity for percent reduction in flag smut disease severity and increase in seed yield of wheat. The experiment was laid out in flag smut infested soil along with external addition of flag smut inoculums (1 g m row-1/12g plot-1) with ground infested leaves using seeds of wheat cultivar C306. The observations on disease severity and seed yield per plot were recorded. Analysis of variance was conducted and means were compared to know the percent reduction in disease severity of flag smut and increase in seed yield in treatment plots, as compared to control plots. The disease severity in NK-1, ST-7 and HR-23 treated plots was only 43.68, 44.35 and 44.35% of control plots, respectively. Thus the treatment with these strains led to 56.3, 55.65 and 55.65% reduction in flag smut disease severity, respectively. Also, the bioinoculation with these strains led to considerable increase in the grain yield of C306 i.e., 4.1% (NK-1), 8.51% (ST-7) and 19.7 (HR-23), respectively. Our findings suggest that bioinoculation of wheat with Azotobacter/Gluconacetobacter strains is satisfactory in controlling the flag smut.

Wheat (T. aestivum) is an important source of carbohydrates, proteins, vitamins and minerals. The crop occupies about 27% of the total area under cereal production worldwide. Among the biotic constraints, smut diseases of wheat are important because they affect yield, quality of wheat grain and its products, and therefore subjected to domestic and international phytosanitary regulations. Flag smut (Urocystis agropyri) incidence is wide spread and is reported from many countries (Karwasra, 2008; and Bhatnagar et al., 1978). The disease is evident from the late seedling stage until maturity of the crop. The pathogen is soil as well as seedborne. Seed infestation is more important than soil inoculum alone and disease symptoms appear after 4-17 days earlier in late sown wheat (Beniwal, 1992). The pathogen is reported to survive in soil for many years. Most of the commercially grown wheat varieties in India are susceptible to this disease and the incidence of flag smut is reported from different parts of India. Several factors like soil moisture, temperature, depth of sowing, previous sowing, previous crops and varietal resistance affect the disease development. The biological control for disease management through the use of bioagents holds promise; however, in wheat, efforts in this direction are recent and very few. The biological control has attracted attention in the recent past for the management of seed and/or soilborne diseases like loose smut (Ustilago segetum tritici.), flag smut (Urocystis agropyri) and Karnal bunt (Nevotia indica). Till now, various bioagents have been tried against loose smut and Karnal bunt disease of wheat. The possible disease control of flag smut with biofertilizer/bioagents, e.g., Azotobacter, Trichoderma, was reported by Beniwal and Karwasra (1996). Maximum disease reduction was provided by T. viride, followed by T. harzianum and minimum by Mycorrhiza (Chhabra et al., 1999). Increased biocontrol activity may be achieved alone or in combination with two or more bioagents producing various metabolites, the combined activity with antifungal compounds produced by the bacterial agents may expand the spectrum of pathogens that can be controlled. Keeping the importance of this aspect, an experiment was carried out with a view to studying the effect of inoculation of selected bacteria having antifungal activity and testing them on the percent reduction in disease severity by flag smut and seed yield of wheat in flag smut infested soil, along with external addition of flag smut inoculums.

Genetics & Evolution Journal, CEL-I Endonuclease, Heterozygous Mutants, Homozygous Mutants, Biological Processes, Plant Mutants, Solanum Lycopersicon, Microcentrifuge Tubes, Homozygous Plants, Plant Genes, Cross Pollination, Heteroduplex Formation.