واکنش‌های فیزیولوژیکی و زراعی ارقام مختلف کینوا (chenopodium quinoa willd) به هیدروپرایمینگ در شرایط تنش خشکی

آزمایشی به صورت اسپلیت پلات فاکتوریل در قالب طرح بلوک های کامل تصادفی با چهار تکرار در سال 1398 در مزرعه پژوهشی ایستگاه تحقیقات پسته دامغان اجرا شد. تیمارهای آزمایش شامل تنش خشکی در سه سطح 100 (شاهد)، 75 و 50 درصد براساس نیاز آبی گیاه به عنوان عامل اصلی، رقم در سه سطح titicaca، q26 و q29 و پرایمینگ در دو سطح عدم پرایمینگ و هیدروپرایمینگ به عنوان عامل فرعی در نظر گرفته شدند که به صورت فاکتوریل در تیمار فرعی خرد شدند. تنش خشکی شدید سبب کاهش شاخص پایداری غشاء برگ (2/21 درصد)، مقدار کلروفیل (38/7 درصد)، محتوای نسبی آب برگ (13/1 درصد)، وزن هزار دانه (18/2 درصد)، تعداد پانیکول در بوته (27/5 درصد)، تعداد دانه در پانیکول (7/71 درصد) و عملکرد دانه (40/4 درصد) گردید. استفاده از هیدروپرایمینگ موجب افزایش شاخص پایداری غشاء (55/3 درصد)، مقدار کلروفیل برگ (16/7 درصد)، وزن هزار دانه (5/31 درصد) و نیز تعداد پانیکول در بوته (15/3 درصد) شد. فعالیت آنزیم های آنتی اکسیدان شامل کاتالاز و آسکوربات پراکسیداز برگ در شرایط تنش 50 درصد نیاز آبی نسبت به شاهد به ترتیب 139/5 درصد و 42/5 درصد افزایش یافت. تنش خشکی هم چنین موجب افزایش درصد پروتئین بذر و نیز کاهش عملکرد دانه در کینوا گردید. در شرایط تنش خشکی، بین سه رقم مورد بررسی اختلاف معنی داری مشاهده نشد. رقم titicaca نسبت به سایر ارقام به خشکی مقاوم تر بود و در منطقه دامغان کشت این رقم پیشنهاد می گردد. بر اساس نتایج این پژوهش، کاربرد هیدروپرایمینگ در جهت بهبود صفات فیزیولوژیک در گیاه کینوا در شرایط تنش خشکی پیشنهاد می شود.

agrophysiological response of different cultivars of chenopodium quinoa willd to hydropriming under drought stress conditions

introduction: the cultivation of quinoa (chenopodium quinoa willd), an annual plant with high nutritional and economic significance, is expanding throughout the world. quinoa is a traditional andean seed crop highly tolerant to abiotic stresses. since most seed crop cultivars are sensitive to drought stress, quinoa is regarded as a valuable candidate for the plant’s exposure to harsh environmental conditions. due to the importance of quinoa in arid regions, the effects of seed priming on yield and certain morphological and physiological traits were investigated in this study.material and methods: a factorial split-plot experiment based on a randomized complete block was designed with four replications was conducted in 2019 at damghan research farm station. the experimental treatments included drought stress based on the plant’s water requirement at three levels (100% (control), 75%, and 50%) as the main factor, and sub-factors included three cultivars (titicaca, q26, and q29) as well as priming at two levels (no priming and hydropriming) as a factorial experiment into sub-levels. to perform water requirement (wr) treatment, wr were calculated using the cropwat program and then applied to the 6-leaf stage plants.results and discussion: the results demonstrated that drought stress (50% wr) reduced  relative leaf water content (13.1%), leaf membrane stability index (21.2%), chlorophyll content (38.7%), 1000-seed weight (18.2%), number of panicles per plant (27.5%), number of seeds per panicle (7.71%), and seed yield (40.4%). the use of hydropriming increased the membrane stability index, leaf chlorophyll content, 1000-seed weight, and the number of panicles per plant. under 50% wr, the activity of antioxidant enzymes such as catalase and leaf ascorbate peroxidase increased by 139.58 and 42.55 percent, respectively, compared to the control. additionally, drought stress increased quinoa seed protein content and decreased seed yield.. the percentage of seed yield reduction in drought stress was 50% and 75% of wr and was lower in titicaca than the other two cultivars.  the comparison of the mean of irrigation interactions in the cultivars revealed that 100% wr produced the maximum quantities of chl a, chl b, and carotenoids in all three cultivars. additionally, seed priming boosted the chl a, and chl b concentrations in titicaca and q26. furthermore, the highest biological yield in the damghan region was achieved in q26 with 100% wr. under normal irrigation conditions, q26 cultivar had the highest seed yield, whereas under drought stress conditions, the seed yield of all cultivars decreased significantly. nevertheless, this decline in the titicaca cultivar was 12% less than in q26 and q29. the findings of the mean comparison revealed that priming improved seed yield in all three cultivars, with the q29 cultivar producing the maximum seed yield at 1,452.03 kg/ha.conclusion: in general, titicaca cultivar was more resistant to drought stress than other cultivars, hence its cultivation is encouraged in the damghan region. within the scope of this study, the use of hydropriming to improve quinoa’s physiological features in conditions of drought stress is suggested. in conclusion, the results demonstrated that seed priming significantly increased seed yield, biological yield, leaf area index, and chlorophyll content in drought-stressed quinoa cultivars. these results indicated that seed priming can play a significant role in enhancing quinoa’s drought resistance under low irrigation conditions. this study could contribute to the understanding of seed priming effects, which could be applied as an effective strategy to mitigate the negative effects of drought stress on quinoa cultivars.