Physiological, biochemical, and grain yield responses of wheat cultivars to Azospirillum brasilense under dryland conditions

The combined use of improved wheat cultivars and growth-promoting bacteria offers a promising strategy for enhancing wheat (Triticum aestivum L.) performance under dryland conditions. This study evaluated the response of different wheat cultivars to inoculation with Azospirillum brasilense Sp۷ in a field setting. The experiment was conducted during the ۲۰۲۱–۲۰۲۲ growing season at the Faculty of Agriculture, Ilam University, under rainfed conditions. A factorial arrangement within a randomized complete block design was used, with three replications. The treatments included Azospirillum inoculation (with and without) as the main factor, and four wheat cultivars (Ivan, Sardari, Homa, and Azar ۲) as subplots. The bacterial inoculant was applied to seeds prior to sowing. Physiological and biochemical traits were measured at the late flowering stage (Zadoks stage ۶۹), including proline content, leaf relative water content (LRWC), electrolyte leakage (EL), photosynthetic pigment levels, net CO۲ assimilation rate (Pn), leaf temperature (Lt), and transpiration rate (Tr). The results showed that seed inoculation did not significantly influence proline accumulation. However, chlorophyll content was the highest in the Ivan cultivar when inoculated. Inoculated plants also exhibited reduced electrolyte leakage compared to non-inoculated controls. LRWC, Pn, and Tr were significantly influenced by both cultivar and bacterial inoculation. Across cultivars, Azospirillum inoculation led to increases in LRWC (۱۳.۷%), Pn (۱۶.۱%), and Tr (۲۴.۳%). Additionally, grain nitrogen and protein content varied among cultivars and responded positively to Azospirillum inoculation.

کلیدواژه ها:

Bacterial inoculation ، Chlorophyll content ، Plant genotype ، Proline ، Rainfed condition