Interactions amongst mycorrhiza, Azotobacter chroococcum and root characteristics of wheat varieties

A field experiment was conducted in a randomized block design with three replications over 2 years to evaluate the effect of wheat cultivar and dual inoculation of Azotobacter chroococcum (Azc) and arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum ) on root characters and AMF infection in three crosses of wheat. The experimental material comprised four wheat parents, WH-147, WH-157, WH-542 and PBW-175, and three F-1 crosses, WH-147 xWH-157, WH-147 x WH-542 and WH-147 x PBW-175. Comparison of treatment averages, i.e. control (mineral nutrients 60 kg N + 30 kg P-2 O-5 + 12.5 kg ZnSO4 ha(-1) , as in other two treatments), AMF and AMF + Azc, revealed that inoculation of Azc led to an increase in AMF infection in roots. Maximum root biomass was obtained in F-1 hybrids WH-147 x WH-157 in the AMF treatment and in WH-147 x PBW-175 receiving AMF + Azc. Total root length and AMF infection of roots was maximum in WH-147 x PBW-175 for all the treatments during both years. A positive association between AMF infection in roots and Azotobacter survival in the rhizosphere was apparent. Similarly, maximum A. chroococcum counts were observed 80 and 120 days after sowing in the AMF + Azc treatment in cross WH147 x PBW175.