تاثیر محلول‌پاشی با اسید سالسیلیک بر تخفیف اثرات تنش سرمازدگی و خشکی بر عملکرد و صفات زراعی در ذرت (Zea Mays L.)

به‌منظور بررسی تاثیر اسید سالسیلیک بر تخفیف اثرات تنش سرمازدگی و خشکی بر عملکرد سینگل کراس 400ذرت، آزمایشی به‌صورت کرت‌های دو بار خردشده در قالب طرح بلوک کامل تصادفی در سه تکرار در گلخانه و مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه فردوسی مشهد در سال 1394اجرا شد. عامل اصلی تنش سرما در دو سطح (عدم تنش سرمازدگی و تنش سرمازدگی به مدت 12 ساعت در دمای 5 درجه سانتی‌گراد در مرحله چهار برگی)، عامل فرعی شامل سه سطح آبیاری (100، 75 و 50 درصد نیاز آبی گیاه) و عامل فرعی فرعی محلول‌پاشی با اسید سالسیلیک (عدم محلول‌پاشی (شاهد)، محلول‌پاشی 200 میکرو مولار و محلول‌پاشی 400 میکرو مولار) در نظر گرفته شدند. اولین زمان محلول‌پاشی قبل از اعمال تنش سرمازدگی در شرایط کنترل‌شده بود و پس از کشت گیاهان در مزرعه هر 15 روز یک‌بار تکرار شد. نتایج نشان داد تنش سرمازدگی اول فصل تاثیر معنی‌داری بر صفات موردبررسی نداشت. اثرات تنش خشکی و اسید سالسیلیک بر صفات مورد آزمایش معنی‌دار بود. اثرمتقاب لتنش خشکی و اسید سالسیلیک برعملکرد دانه،عملکردبیولوژیکی، شاخص برداشت، کارایی مصرف آب و بهره‌وری آب معنی‌دار بود. اثر اسید سالسیلیک بر بهبود رشد و افزایش عملکرد در هر دو شرایط تنش و غیرتنش معنی‌دار بود. بالاترین عملکرد دانه و بیولوژیک به ترتیب با میزان 8543 و 18220 کیلوگرم در هکتار مربوط به تیمار آبیاری مطلوب با محلول‌پاشی 400 میکرو مولار بود. درمجموع اسیدسالسیلیک باغلظت 400 میکرو مولار سبب بهبودعملکردذرتشد و اثرات منفی تنش‌های سرما و خشکی را بر عملکرد گیاه ذرت کاهش داد.

The effect of salicylic acid on alleviating the frost and drought stress on yield and related traits of maize hybrid SC400 (Zea mays L.)

IntroductionPlants are affected by many unfavorable environmental factors and therefore crop growth and development is retarded. Cold and water stress impose a considerable damage to the economy and country’s agricultural production every year. Salicylic acid is of phenolic compounds which is found in many plants, and considered as quasi hormonal substance that plays an important role in the growth and development of plants. Salicylic acid plays an important role in resistance to environmental stresses. The aim of this study was to investigate the effects salicylic acid spraying on alleviating the chilling and drought stresses on yield and agronomic traits of maize single cross 400.Materials and methodsThis experiment was performed as a splitsplit plot in a randomized complete block design with three replications during 1394 in the greenhouse and the Research Farm of Faculty of Agricultural Ferdowsi University of Mashhad. The main plot of cold stress at two levels (nonstress and cold stress at 5ºC for 12 hours at 4th leaf stage), sub factors were three levels of irrigation (100, 75 and 50% of water requirement) and subsub plot was spraying with salicylic acid (non (control) , 200 and 400 µM spraying After cold stress, seedlings of Single cross 400 were planted in the field. The plots were prapared with four meters length and three meters widths and row spacing of 75 cm with 75000 plants per hectare. At the end of the growing season to determine yield components, five plants were randomly taken from each plot from one square meter and biomass and kernel yield was recorded. MSTATC software implemented for statistical analysis and the means were compared using LSD test.Results and discussionThe effect of drought stress and salicylic acid on the seed number per plant was significant. So that 100% irrigation %cause to improve 34.2% %in seed number per plant compared to 50% %of water requirement. Spraying plants with 200 and 400 µM improved the trait at a rate of 13.6 % compared to nonspraying (control). Effects of drought stress, salicylic acid and interaction of salicylic acid with drought on seed yield were significant. The treatment of 100% water requirement with 400 µM spraying with an increase of 54.3% showed the highest seed yield compared to 50% water requirements with spraying. In another study also corn foliar spaying with salicylic acid in flowering stage increased seed yield (Bayat et al., 2010). Effects of drought stress and salicylic acid and their interaction on biological yield were significant. The highest biological yield was obtained in 100% water treatment with 400 µM salicylic acid spraying with 55.2% higher biomass compared to 50% water treatment with similar salicylic acid spraying.Harvest Index in treatment of 400 µM salicylic acid spraying in irrigation conditions of 100% water requirement was 11.1% more than in irrigation conditions of 50% water requirement with the same salicylic acid spraying. Setter et al (Setter et al., 2001) similarly reported that corn grain yield reduced under drought stress.ConclusionsThe results of this study showed that cold stress did not have negative impact on SC400 corn hybrid on tested traits. But the drought stress reduced corn yield components (such as the number of seeds and rows in corn), seed weight, biological yield, seed yield, and harvest index. 400 µM salicylic acid applications can be significantly increased biological yield and seed yield SC400 corn.