Effects of supplementary irrigation and application of mycorrhiza and azetobacter on grain filling components of rain fed barley (Hordeum vulgare L.)

In order to study the effects of supplementary irrigation and application of mycorrhiza and azetobacter on grain filling components, chlorophyll content, and grain yield of rain fed barley (Var. Sahand), a factorial experiment was conducted based on a randomized complete block design with three replications in the village of Khalkhoran Viand, Ardabil province during 2017. Factors of the experiment included irrigation levels (no irrigation as rain fed, supplementary irrigation at 50% heading, and booting stages) and biofertilizers application at four levels (without biofertilizers as control, application of mycorrhizal fungi, application of azetobacter, and combined application of mycorrhiza and azetobacter). Results showed that the highest chlorophyll a (1.76 mg/g FW), chlorophyll b (0.88 mg/g FW), carotenoid (0.83 mg/g FW), chlorophyll total contents (2.64 mg/g FW), maximum fluorescence (1433.2), variable fluorescence (1281.3), quantum yield (0.847), grain filling period (32.06 days), and maximum grain weight (58.3 mg) were obtained under supplementary irrigation treatment at boot stage with both application of mycorrhiza and azetobacter while the minimum levels of these traits were obtained under rain fed condition without application of biofertilizers. Moreover, the highest grain filling rate (1.9 mg/day) was obtained under rain fed condition and no application of biofertilizers while the lowest rate was obtained under supplementary irrigation at boot stage with application of mycorrhiza. Supplementary irrigation at boot stage and combined application of mycorrhiza and azetobacter increased grain yield by 29.87% in comparison with no application of biofertilizers under rain fed condition. Based on the results, it seems that application of biofertilizers and supplementary irrigation can increase grain yield of rain fed barley through improving chlorophyll content and grain filling components.