Mycorrhizal symbiosis and glycine betaine effect foliar application on some agronomic traits of rainfed wheat in calcareous soils

In order to investigate the effect of mycorrhizal fungi symbiosis and glycine betaine foliar application on some quantitative and qualitative characteristics of rainfed wheat, this experiment was carried out in the Rainfed Research Station of Agricultural and Natural Resources Education and Research Center of West Azerbaijan, Iran during 2017-19 cropping seasons. The experiment was performed as a factorial randomized complete block design with three replications. The first factor was mycorrhizal fungi inoculum at three levels: (1) control, (2) inoculation of seeds before sowing with mycorrhizal fungus inoculum of  Rhizaphagus irregularis (GI) at a rate of 2%, (3) inoculation of seeds before sowing with mycorrhizal fungi inoculum as a mixture of three species of Funneliformis mosseae, Rhizaphagus irregularis  and Claroideoglomus etunicatum  (GM) at a rate of 2% and the second factor was glycinebetaine in two levels (1) control (water spraying) and foliar application of glycinebetaine. The results showed that root colonization was significantly affected by mycorrhizal fungal treatments and increased from 9.89% in control to 30.57% and 40.71% in GI and GM treatments, respectively. Using GM and GI inoculum, wheat grain yield increased by 269 and 187 kg ha-1, respectively. Application of mycorrhizal inoculum increased grain protein content and concentration of phosphorus (P) and zinc (Zn) in the grain. In all the mentioned traits, GM treatment had higher efficiency than GI treatment. Glycine betaine increased seed yield by 160 kg/ha. Foliar application of glycine betaine increased grain yield by 160 kg ha-1. The highest grain yield in GM treatment + glycine betaine foliar application was 2163 kg ha-1 which was 196 kg more than the control treatment. Generally, the results suggested that the application of MI inoculant + foliar application of GB were highly effective in improving the grain yield, harvest index, and quality parameters of rainfed wheat in semi-arid regions.