Abstract

The main aim of this study is to evaluate efficiency of four bioagents, Bacillus subtilis(isolate BSM1), Bacillus megaterium (isolate BMM5), Trichoderma viride (isolate TVM2) and Trichoderma harzianum (isolate THM4) for the control of rot pathogensFusarium graminearum, Drechslera halodes and Rhizoctonia solani on two wheat cultivars (Sakha 93 and Bani Suif 5) under greenhouse conditions. Moreover, their effect on wheat growth and yield were also studied under field conditions. In vitro, all tested bioagents significantly reduced redial growth of the pathogenic fungi. T. viridewas active more than the other tested bioagents followed by T. harzianum, while B. subtilis was the least ones. Under greenhouse conditions, all tested bioagents were able to reduce significantly damping-off and root rot caused by the tested pathogens compared with control and increased fresh and dry weight of the survival plants when applied as soil or grain treatments however, there was variation among bioagent isolates effect on reduction of disease severity both application methods. T. viride andB. megaterium were recorded the highest effective in this respect compared with other tested bioagents. Under field conditions, analysis of variance and mean performance were estimated for four characters: grain yield 4.8 m^-2, No. of spikes m^-2, No. of kernels spike^-1 and 1000-kernel weight. Significant mean squares were obtained for all studied characters between the seasons (S), methods (M), (S) × (M), treatments (T), (S) × (T), (M) (T) and interaction (S) × (M) × (T) for Sakha 93 cultivar and Bani Suif 5 cultivars except application methods and (S) × (M) for number of kernels spike^-1 and 1000-kernel weight, respectively. While the treatments T. harzianum and B. megaterium were best treatments to increase grain yield, the treatments B. subtilis and T. harzianum were best treatments to increase number of spikes and the treatments B. subtilis and B. megaterium were best treatments to increase number of kernels for  soil and grain application methods, respectively.

Key words:  Bio-agents, root rot disease, wheat growth, yield and yield components