استفاده از حافظه تنش برای بهبود تحمل تنش خشکی در سیب‌زمینی

شناخت و بهره‌گیری از کارکردهای فیزیولوژیک گیاهی می‌تواند در مقابله با تنش‌های محیطی مانند تنش خشکی به‌کار برده شود. پژوهش حاضر به‌منظور بررسی تاثیر وقوع تنش خشکی در سال‌های قبل، بر تولید سال جاری چهار رقم سیب‌زمینی انجام شد. به این منظور از آزمایش کرت‌های خردشده در قالب طرح بلوک‌های کامل تصادفی با سه تکرار استفاده شد. عامل اصلی شامل دو سطح آبیاری (آبیاری کامل در رطوبت ظرفیت مزرعه و آبیاری در 75 درصد رطوبت ظرفیت مزرعه) و عامل فرعی شامل هشت سطح (چهار رقم آگریا، مارفونا، آتوسا و آنوشا در دو حالت مقاوم شده و مقاوم نشده به خشکی) بودند.نتایج نشان داد کهتاثیر برهمکنش عوامل آبیاری و رقم بر صفت عملکرد کل در سطح پنج درصد و بر عملکرد غیرقابل فروش، عملکرد قابل‌فروش و بهره‌وری آب در سطح احتمال یک درصد معنی‌دار بوده است. کاهش عملکرد در شرایط تنش خشکی برای ارقام آگریا، مارفونا، آتوسا، آنوشا که مقاوم‌سازی به خشکی در آن‌ها انجام ‌نشده بود به‌ترتیب برابر با 30.6، 27، 39.7 و 38.9 درصد بود. در شرایط تنش خشکی و استفاده از ارقام مقاوم شده به خشکی، کاهش عملکرد دو رقم آتوسا و آنوشا فقط 8.5 درصد بود. ارقام آتوسا و آنوشا به‌ترتیب با شاخص تحمل به تنش 0.72 و 0.67 درصد نسبت به دو رقم مارفونا و آگریا برتری معنی‌دار داشتند. با توجه به نتایج به نظر می‌رسد در برخی از ارقام از حافظه تنش می‌توان در جهت تعدیل اثرات تنش در کشت‌های بعدی استفاده نمود.

The Use of Stress Memory to Improve Drought Stress Tolerance in Potato

Introduction Potato (Solanum tuberosum L.) as a drought sensitive crop is one of the main sources of human nutrition in different countries and it is cultivated almost all over the world. It is predicted that among the 25 studied countries, the decline in potato yield in Iran between 2040 and 2069 will be 13.3% for droughtadapted cultivars and 48.3% for nondroughtadapted cultivars. Annually 164.4 thousand hectares of agricultural lands in Iran are allocated to potato cultivation with a yield of 32.4 t ha1. Nowadays, plant biology is experiencing great advances in studies related to the complex behavior of higher plants, and stress memory is one of these progresses. Stress memory involves the accumulation of signaling proteins or transcription factors and epigenetic mechanisms in plants that leads to an improvement in the stress response when plants are exposed to a subsequent stress event. “Stress memory” in plants is also an essential feature of “intelligent” behavior and can be investigated at different levels. Materials and Methods In order to investigate the effect of drought stress on yield and yield components of four potato cultivars, a study was conducted in 2020 in Rozveh Agricultural Research Station, Chadegan city. Half of the required seed tubers were obtained from the previous year’s experiment. The treatments were laid out in a split plot arrangement in a randomized complete block design with three replications. Main plots included two irrigation treatments (100% and 75% of the field capacity) and subplots included four potato cultivars (Agria, Marfona, Atousa, and Anousha). Each plot consisted of four rows with four m length and 75 cm × 25 cm of plant density. At harvest time, two meters of the middle rows of each plot were used to estimate yield and yield components. Stress tolerance index and water use efficiency were investigated in this study. SAS software (version 9.1) was used to analyze the data and Duncan’s multidomain comparison method (5%) was used to compare the means. Results and Discussion The effect of irrigation treatment on total yield, marketable and nonmarketable yield, and on water use efficiency was statistically significant at the level of 1% and 5%, respectively. The effects of interaction between irrigation treatment and cultivar on total yield was significant at 5% probability level, and on nonmarketable yield, marketable yield, and water use efficiency were significant at 1% probability level. The total yield in 8 experimental treatments under full irrigation conditions ranged from 30 to 39 t ha1. In full irrigation conditions, Agria was the only cultivar that produced a significantly higher yield than other cultivars. Among the nonresistant cultivars, Atousa and Anousha cultivars experienced a greater yield decline of 40% and 39%, respectively, than Agria and Marfona cultivars. In drought stress conditions, two resistant cultivars, Atousa and Anousha, had the highest yield compared to other cultivars and the lowest yield compared to adequate water supply conditions (only 8.5% yield loss). Droughtresistant Atousa and Anousha cultivars with water use efficiency of 7.1 and 7.6 kg m3, respectively, compared to the nonstress condition (6.1 and 6.2 kg m3, respectively) had significant superiority. Conclusions The results indicated that not only drought tolerance is different in different potato cultivars but also stress memory is different in different cultivars. The use of tubers that have been exposed to drought stress (drought tolerant) during previous growth stages can affect plant behavior in the current growth. According to the results, it seems that in some cultivars, stress memory can be used to moderate the effects of stress in subsequent cultures.