بررسی پاسخ عملکرد دانه گندم (triticum aestivum l.) به محلول‌پاشی با باکتری آزوسپیریلوم، هورمون بنزیل آمینو پورین و روی

بخش قابل‌توجهی از گندم تحت شرایط دیم تولید می‌شود. بنابراین، حفظ عملکرد و افزایش کیفی دانه گندم ‏تحت کشت دیم ضروری است. دو آزمایش مزرعه‌ای جهت ارزیابی تاثیر محلول‌پاشی با روی، هورمون بنزیل ‌آمینو ‌پورین و محلول‌پاشی با باکتری آزوسپیریلوم بر گندم ‏رقم سرداری تحت کشت دیم انجام گرفت. در آزمایش اول که به‌صورت آزمایش فاکتوریل در قالب طرح بلوک کامل تصادفی اجرا گردید، تاثیر چهار سطح روی (0، 0.2، 0.3 و 0.4 درصد) و دو سطح هورمون (0 و 10 میلی‌گرم در لیتر) بر عملکرد و محتوای روی دانه بررسی گردید. محلول‌پاشی پس از مرحله گرده‌افشانی انجام گرفت. براساس بهترین ترکیب تیماری حاصل از آزمایش اول، تاثیر کاربرد 0.3 درصد روی به‌تنهایی و یا در انواع ترکیب‌های مختلف با آزوسپیریلوم برازیلنس و بنزیل ‌آمینو ‌پورین ‏در سال زراعی 1402-1401 در آزمایشی فاکتوریل بر پایه طرح بلوک کامل تصادفی و در سه تکرار مورد ارزیابی قرار گرفت. تاثیر هورمون بر افزایش عملکرد فقط در سال اول انجام آزمایش معنی‌دار بود. میزان عملکرد دانه تحت کاربرد غلظت‌های 0، 0.2، 0.3 و 0.4 درصد روی به‌ترتیب 2673، 2930، ‏‏2997 و 3086 کیلوگرم دانه در هکتار بود. محلول‌پاشی با روی، محتوای روی دانه را از 23.3 (شاهد) به 27.9 میلی‌گرم در کیلوگرم افزایش داد. در بررسی نتایج تلفیق هورمون با روی و باکتری، بیشترین میزان عملکرد دانه از تلفیق باکتری با روی حاصل گردید. بنابراین، کاربرد باکتری و روی از طریق محلول‌پاشی جهت افزایش عملکرد و محتوای روی گندم می‌تواند مورد توجه قرار گیرد.

investigation the response of wheat (triticum aestivum l.) grain yield to foliar application of azospirillum, zn and 6-banzylaminopurine

introductionmany millions of hectares of wheat-cultivated lands are located in semi-arid areas, and cereal crops such as wheat grown under such conditions frequently face drought events during their life cycle. a considerable amount of rainfall in the semi-arid areas of iran occurs in winter; thus, the critical growth period (grain filling) receives little to no rainfall. studies have shown that micronutrients, plant growth regulators, and plant growth-promoting bacteria are able to improve plant performance under drought conditions. the present study aimed to elucidate the effect of foliar application of zn, exogenous application of 6-benzylaminopurine, and foliar inoculation with azospirillum on wheat performance under rain-fed conditions.materials and methodsthe present study consisted of two field experiments, carried out in a semi-arid area. experiment 1 was conducted during the 2020/21 and the second one during 2022-203 wheat growing season. the effect of four different levels of zn application (0, 2, 3, and 4 kg zn ha-1) via foliar application was investigated on wheat yield, yield components, and seed zn content under exogenous application of two levels of 6-benzylaminopurine (0 and 10 mg l-1) under rain-fed conditions. the experimental design was a 4×2 factorial combination of zn application and 6-benzylaminopurine exogenous application arranged in a randomized complete block design with three replications. the experimental plot size was 1 m × 2 m, and the wheat cultivar sardari was used in the experiments. foliar application was applied at the flowering stage (zadok’s growth stage 65). based on the results obtained from the first experiment, a subsequent field study (second experiment) was performed to elucidate the efficacy of the foliar application of zn (3 kg zn ha-1) and 6-benzylaminopurine (10 mg l-1) in the presence and absence of foliar inoculation with azospirillum. the second experiment was conducted in the 2022-2023 wheat growing season. wheat response to foliar application of 0.3% (w v-1) znso4, 10 mg l-1 6-benzylaminopurine, and foliar inoculation with azospirillum brasilense sp7 was investigated under rain-fed conditions. the plant canopy was inoculated with 10% of 108 colony-forming units of azospirillum strain sp7. all foliar applications were applied at anthesis (zadok’s growth stage 65). the experimental design for this experiment was a factorial scheme based on a randomized complete block design with three replications. the wheat variety used for the experiments was sardari.results and discussionthe application of zinc (zn) significantly affected the seed number, whereas the application of 6-bap and its interaction with zn did not have a significant impact. the highest seed number per head was observed with zn application at 3 kg ha⁻¹, followed by 2 kg ha⁻¹. the highest zn application had a negative effect on seed number per head. the effect of foliar application level and 6-bap and their interaction on grain weight and grain yield was significant. application of 3% (w v-1) (3 kg zn ha-1) yielded the highest grain weight and grain yield, and higher application of zn had a negative effect on grain weight and yield. foliar-applied 6-benzylaminopurine (10 mg l-1) significantly improved grain weight and grain yield. improved grain weight and grain number per spike affected total grain yield. the highest grain yield was achieved with 3 kg zn ha-1 (0.3% (w v-1) zn plus 10 mg l-1 6-bap). applied zn significantly increased zn content in grains. the highest grain zn content was obtained in plants that were sprayed with 4 kg zn ha-1 and 10 mg l-1 6-bap. results of the second experiment revealed the efficacy of azospirillum in the improvement of grain weight and grain yield. in the second year of the study, the effect of exogenous application of 6-bap on yield and yield components was not significant, which might be attributed to the precipitation rate. however, foliar inoculation with azospirillum and foliar application of zn significantly affected grain yield. the highest grain yield was obtained from plants foliar-applied with zn plus azospirillum.conclusionmicronutrients, plant growth regulators, and biofertilizers have the ability to improve plant performance, especially under environmental constraints. the present study, carried out under rain-fed conditions, investigated the effect of azospirillum brasilense, zn nutrition, and 6-benzylaminopurine applied foliarly on the wheat cultivar sardari. overall, the application of zn at a rate of 3 kg per ha combined with foliar inoculation with *azospirillum* produced the best results for wheat performance. additionally, zn also improved zn content in the grain. as a result, farmers can improve the productivity of winter wheat yield by utilizing a small amount of zinc fertilizer (3% (w v-1) (3 kg zn ha-1) and the plant-growth promoting bacteria azospirillum at the flowering stage.