بررسی تحمل ژنوتیپ‌های امیدبخش سیب‌زمینی به تنش خشکی در منطقه اردبیل

کمبود آب یکی از مهم‏ترین عوامل محدودکننده تولید گیاهان در مناطق خشک و نیمه خشک ایران می ‏باشد. به منظور گزینش ژنوتیپ‏ های سیب ‏زمینی متحمل به تنش خشکی، آزمایشی در قالب طرح پایه بلوک های کامل تصادفی به روش بلوک ‏های خرد شده نواری در سه تکرار طی دو سال زراعی 97-1396 و 98-1397 در منطقه اردبیل اجرا شد. تیمارهای افقی شامل 20 ژنوتیپ سیب‏ زمینی و تیمارهای عمودی شامل تنش و عدم تنش خشکی از طریق قطع آبیاری بودند. نتایج نشان داد تیمار تنش موجب کاهش معنی ‏دار در وزن غده و عملکرد غده در همه ژنوتیپ ‏ها شد. بیش‏ترین وزن غده در بوته و عملکرد غده با کم‏ترین کاهش نسبت به شاهد متعلق به ژنوتیپ 905675 و کم‏ترین مقدار این صفات مربوط به رقم مارفونا با بیش‏ترین درصد کاهش نسبت به شاهد بود. به علاوه درصد نشاسته،درصد ماده خشک و میزان پروتئین با عملکرد غده رابطه معکوس داشته و افزایش داشتند. نتایج نشان داد که در بین ژنوتیپ‏ های مورد مطالعه، در شرایط تنش ژنوتیپ 901375 از بیش‏ترین درصد ماده خشک و ژنوتیپ 901375 از بیش‏ترین درصد نشاسته برخوردار بودند. بالاترین بهره‏ وری مصرف آب در شرایط تنش مربوط به ژنوتیپ 905675 با عملکرد 9.89 کیلوگرم بر مترمکعب به دست آمد. از نظر شاخص ‏های تنش نیز ژنوتیپ ‏های 901375، 905676 و 901675 با بیش‏ترین مقدار عددی در هر چهار شاخص مورد ارزیابی به‏ ترتیب دارای پتانسیل بالای تحمل در شرایط تنش بودند. به ‏طور کلی با در نظر گرفتن میزان تغییرات عملکرد غده، وزن غده در بوته، هم‏چنین افزایش صفات نشاسته، ماده خشک، میزان پروتئین و بهره ‏وری مصرف آب و شاخص ‏های تنش، ژنوتیپ های 905675، 901575 و 901375 به‏ ترتیب به‏ عنوان ژنوتیپ ‏های متحمل و پتانسیل بالای عملکرد در هر دو شرایط تنش و عدم تنش انتخاب شدند. بنابراین، این ژنوتیپ ‏ها را می ‏توان جایگزین مناسب برای رقم پر سابقه آگریا در منطقه اردبیل و هم‏چنین ارقام میلوا، جلی و مارفونا را به‏ عنوان ارقام حساس معرفی نمود.

evaluation of tolerance of promising potato genotypes to drought stress in ardabil region

extended abstract 1.    introduction: water deficit is one of the most important factors limiting plant production in arid and semi-arid regions of iran. potatoes are highly sensitive to drought stress at all stages of development, especially the tuber formation stage. using genotypes that are adaptable and tolerant to water deficit is one of the main methods of preventing the reduction of agricultural production in arid regions. this study aimed to select drought-tolerant genotypes by examining water use efficiency, tuber yield, tuber weight per plant, and some potato quality traits including dry matter, starch, and protein of 20 potato genotypes in the ardabil region.2.    materials and methods: in order to select drought tolerant genotypes, an experiment in the form of a randomized complete block design with split strip blocks in three replications during the two cropping years 2018 and 2019 in ardabil region accomplished. horizontal treatments included 20 potato genotypes and vertical treatments included drought stress and no stress.in order to select droughttolerant genotypes, an experiment in the form of a randomized complete block design with split strip blocks in three replications during the two cropping years 2018 and 2019 in ardabil region accomplished. horizontal treatments included 20 potato genotypes and vertical treatments included drought stress and no stress. genotypes were obtained from the ardabil agricultural and natural resources research station based on ten-year selection in terms of yield and quality.  each plot consisted of four lines of four meters in length with a distance between the lines and on the lines of 75 and 25 cm, respectively (64 plants in each plot with an area of 12 square meters). to prevent lateral penetration of moisture, a distance of one and a half meters was considered between adjacent plots, and at the time of harvesting, the effect of the margin was minimized by removing the two side lines and the first and last plants in each row. in both years, sowing was carried out on the sixth day of may.3.    results and discussion: the results showed that stress treatment caused a significant reduction in tuber weight and tuber yield in all genotypes. the highest tuber weight per plant and tuber yield with the lowest decrease compared to the control belonged to genotype 905675 and the lowest value of these traits belonged to marfona cultivar with the highest percentage decrease compared to the control. in addition, starch content, dry matter percentage and protein content were inversely related to potato tuber yield and increased. the results showed that among the studied genotypes under stress conditions, genotype 901375 had the highest percentage of dry matter and genotype 901375 had the highest percentage of starch. the highest water use efficiency under stress conditions was related to genotype 905675 with a yield of 9.89 kg / m3. in terms of stress indices, genotypes 901375, 905676 and 901675 with the highest numerical values in all four evaluated indices had a high potential for tolerance under stress conditions, respectively. potato yield is primarily directly related to the amount of water consumed and is strongly affected by drought stress, and the stability of yield under stress conditions depends on the tolerance of genotypes. for this purpose, a numerical ranking between one and 20 was performed to select the genotypes more favorably. accordingly, the highest and lowest tuber yield, the lowest and highest percentage of change in stress and non-stress conditions were ranked one and 20, respectively. the lowest total rank belonged to genotypes 905675, 901575, and 901375, respectively, which were tolerant genotypes, and the highest total rank belonged to cultivars milva, marfona, and jelli, respectively, which were identified as sensitive cultivar. under stress conditions, the highest productivity (9.89 kg/m3) was related to genotypes 905675 with a 50% increase, followed by 901375 (9.84 kg/m3) with a 35% increase. the lowest productivity was related to the marfona variety with 5.66 kg/m3, and the lowest increase under stress (17%) occurred in the mileva variety. the results showed that the 901375 genotype had high productivity in both non-stressed and stressed conditions. in this experiment, it was found that water use efficiency increased differently in the genotypes by applying stress. this confirms that the higher water use efficiency for potato genotypes under drought stress conditions is an indicator that these varieties have a higher potential for higher yield even under low moisture levels, thus making them suitable for drought conditions.4.    conclusion: in general, considering the rate of changes in tuber yield, tuber weight per plant, as well as increasing starch, dry matter, protein content and water productivity and stress indices, genotypes 905675, 901575 and 901375 in both stress and non-stress conditions, respectively were selected as tolerant and high yield potential genotypes. therefore, these genotypes can be introduced as a suitable alternative to the well-known cultivar agria in ardabil region as well as milva, jeli and marfona cultivars were introduced as susceptible cultivars.