تاثیر سالیسیلیک اسید بر عملکرد کمی و برخی خصوصیات بیوشیمیایی سه رقم جو در رژیم های مختلف آبیاری

به منظور بررسی محلول‌ پاشی اسید‌سالیسیلیک در سه مرحله رشدی بر عملکرد، اجزای عملکرد دانه و برخی پارامترهای بیوشیمیایی سه رقم جو در رژیم‌های مختلف آبیاری، آزمایشی به صورت اسپیلت پلات -‌ فاکتوریل و در قالب طرح بلوک‌های کامل تصادفی با سه تکرار، در دو سال زراعی در شهرستان نی‌ریز اجرا گردید. تیمارهای آزمایشی شامل رژیم‌های آبیاری در سه سطح یک، دو و چهار مرتبه آبیاری به عنوان عامل اصلی و عوامل فرعی شامل ارقام جو (ریحان، نصرت و خاتم) و محلول پاشی اسید‌سالیسیلیک با غلظت یک میلی مولار، در سه مرحله انتهای پنجه‌زنی، اواسط ساقه روی و ظهور پنجاه درصدی برگ پرچم به همراه عدم تیمار مصرف بودند که به صورت فاکتوریل در کرت‌های فرعی قرار گرفتند. نتایج تجزیه مرکب داده‌ها نشان داد یک و دو نوبت آبیاری ‌در مقایسه با چهار نوبت آبیاری اثر منفی بر شاخص برداشت، رطوبت نسبی و مقادیر کلروفیل a و b در برگ‌ها داشت و پرولین برگ افزایش یافت. کمترین واکنش به کاهش دفعات آبیاری مربوط به وزن هزار دانه با 22/1 درصد کاهش بود. اسید‌سالیسیلیک در شرایط کاهش دفعات آبیاری اثر معنی‌داری بر وزن هزار دانه و تعداد دانه در سنبله نداشت، اما موجب بهبود سایر صفات در هر سه رژیم آبیاری شد. میزان افزایش عملکرد توسط اسید‌سالیسیلیک نسبت به شاهد در خاتم (9/5%)، ریحان (10/7%) و نصرت (10/8%) بود. در نهایت، اسید‌سالیسیلیک، به ویژه هنگامی که در پایان پنجه‌زنی اعمال شد، با بهبود ویژگی‌های بیوشیمیایی، تحمل جو به خشکی را بهبود بخشید و عملکرد را افزایش داد.

effects of salicylic acid on quantitative yield and some biochemical traits of three barley varieties under different irrigation regimes

abstract introduction: in the tropical and subtropical regions of iran, the growth and yield of cereals decreases due to the presence of drought stress caused by the increasing decrease of water resources. at the same time, barley is one of the most suitable crops for such conditions. today, the use of plant growth regulators such as salicylic acid has made plants resistant to environmental stresses such as drought. due to the water limitation in iran and the widespread use of barley in animal feeding, this research was carried out to evaluate the effects of different salicylic acid application times on some morphological traits and grain yield of this crop under drought stress.  due to the water limitation in iran and the widespread use of barley in animal feeding, this research was carried out to evaluate the effects of different salicylic acid application times on some morphological traits and grain yield of this crop under drought stress.materials and methods: a field experiment was conducted as a factorial split- plot on a randomized complete block design with three replications were carried out during two cropping years 2019-2020 and 2020-2021in neyriz city.the experimental factors include the number of times of irrigation in three levels of one, two and four times as the main factor, six-rowed barley varieties reihan, nosrat and khatam, the sub factor and the spraying of salicylic acid hormone with a concentration of one mm, in four levels with water (cotrol), tillering end, 50% emergence of stem, and end of flag leaf emergence leaves were as the sub-sub factor. therefore, the experiment included 36 treatments and the whole experiment included 108 experimental units (plots). each experimental plot consisted of eight rows, and the spacing of rows was 20 cm and a density of 350 grains per square meter with dimensions of 1.6 x 4.5 (4.5 meters long and 1.6 meters wide). the interval between the primary plots was 1.5 meters, and the subplot spacing was 0.5 meters. the soil of the experiment site had a silty clay texture, and the water used for irrigation had ph=8.02 and ec=0.2686 ds.m-1. the parameters measured included the number of grain in spike, chlorophylla, chlorophyllb, proline, relative water content, weight of 1000 seeds, biological yield and grain yield. data were analyzed after bartlett's test, proving the homogeneity of test error variance and considering the year as a random variable. variance analysis of the data was done based on the mathematical expectation of change sources using sas ver.9.1 software. the means were compared using tukey's test at the five percent probability level.results and discussion: the results showed that the independent effects of low irrigation treatments, variety and salicylic acid had a significant effect on the content of chlorophyll a and b, proline concentration, number of seeds per spike, biological yield, seed yield and also plant height. based on the results compared with normal conditions, drought stress had a negative effect on the indicators: rwc, chlorophyll a and b, other components related to yield and grain, and also increased proline content. the lowest response to the reduction of irrigation frequency was related to the weight of 1000 seeds with a decrease of 22.1%. spraying salicylic acid solution in drought stress conditions did not have a significant effect on the weight of 1000 seeds and the number of seeds per spike, but it improved other studied traits in both stress and normal conditions. that these positive effects were strongly correlated with the time of foliar spraying and the highest efficiency of salicylic acid application was related to foliar spraying at the end of tillering and results show the highest sensitivity to lack of irrigation in khatam variety compared to other investigated varieties.conclusion: among the barley cultivars, rehan variety had the best performance in the experimental treatments, and in general, spraying salicylic acid solution, especially at the end of the tillering stage, was effective in reducing the effects of drought stress, and under similar water and soil conditions, its use in barley is recommended.