Growth regulation and rust resistance enhancement in wheat via microbial inoculants and various organic soil amendments

Wheat is one of the most significant staple crops, a key contributor to global food security. However, its production is limited by plant diseases, poor soil fertility, and unfavorable environmental conditions. This study aimed to assess the effects of animal waste (6% and 3%), rice husk (6% and 4%), and poultry manure (4% and 2%) as soil amendments in combination with foliar application of two biocontrol agents (BCAs), Trichoderma harzianum and Bacillus sp. MN54, on two wheat varieties (Akbar-19 and Subhani-21). A pot experiment was conducted with three replications to evaluate responses. Results demonstrated that all amendment-inoculant treatments significantly improved plant development compared to the control. Among the tested treatments, higher doses of animal waste and poultry manure combined with T. harzianum were the most effective. Plant height increased by approximately 23%, tillering by about 39%, internodal length by nearly 45%, and peduncle length by more than 60%. Yield components were also enhanced, with grains per spike increasing by about 20–30%, spike weight by 30–40%, and grain weight per spike by 28–43% relative to the control. Rust severity was markedly reduced under amendment-microbe treatments, particularly under T. harzianum combined with poultry manure (4%), which lowered brown rust and yellow rust by around 80–88%. Bacillus sp. MN54 also reduced rust incidence by 60–70%. These findings suggest the potential role of microbial-organic amendment combinations in enhancing wheat productivity and disease resistance in sustainable agricultural systems.