تاثیر تنش شوری بر صفات ریخت‌شناسی و الگوی الکتروفورزی پروتئین‌های رگه های خویش آمیخته نوترکیب آفتابگردان روغنی حاصل از تلاقی pac2 × rha266

به منظور بررسی تغییرات ریخت شناسی 98 رگه خویش آمیخته نوترکیب آفتابگردان دانه روغنی حاصل از تلاقی pac2 × rha266، در شرایط نرمال و تنش شوری 6 دسی‌زیمنس‌برمترمربع آزمایشی بصورت فاکتوریل در قالب طرح کاملاً تصادفی با 3 تکرار در مزرعه تحقیقاتی دانشگاه ارومیه انجام شد. در هریک از شرایط بعد از مرحله گلدهی صفات عملکرد دانه، وزن 100 دانه، تعداد برگ، طول برگ، عرض برگ، طول دمبرگ، قطر ساقه، وزن خشک طبق و روز تا گلدهی اندازه‌گیری شدند. بر اساس نتایج تجزیه واریانس اثر متقابل شوری × رگه برای تمامی صفات به غیر از ارتفاع بوته معنی‌دار بود مقایسه میانگین رگه‌ها در هر دو شرایط نشان داد که میانگین رگه‌ها در شرایط تنش شوری نسبت به شرایط نرمال، در همه صفات بجز طول دمبرگ کاهش یافته است. بیشترین مقدار درصد کاهش در عملکرد دانه (13.23) و وزن صد دانه (10.60) مشاهده شد. نتایج رگرسیون گام به گام نشان داد که صفات قطر طبق و وزن 100 دانه در هر دو شرایط نرمال و تنش شوری وارد مدل شدند. بنابراین انتخاب برای این صفات در هر دو شرایط به بهبود عملکرد دانه کمک خواهد کرد. بر اساس نتایج قسمت اول پژوهش، دو رگه متحمل و حساس به شوری (به ترتیب رگه‌های c86 و c64) انتخاب و الگوی الکتروفورزی پروتئین‌ها در سطوح مختلف تنش شوری صفر، 2، 4، 6 و 8 دسی‌زیمنس‌برمترمربع بررسی گردید. بر اساس نتایج حاصله، الگوی الکتروفورزی متفاوتی برای رگه‌های c86 و c64 در سطوح مختلف تنش شوری مشاهده شد که حاکی از واکنش متفاوت رگه‌ها به تنش شوری می‌باشد. احتمالا باندهای پروتئینی با وزن مولکولی 55 و 83.45 کیلودالتون، پروتئین‌های مرتبط با تحمل به تنش شوری هستند که در رگه متحمل تغییرات بیان نشان می دهند. نتایج حاصل از این پژوهش می‌تواند در برنامه‌های به نژادی آفتابگردان جهت تولید ارقام متحمل به شوری مفید باشد.

The effect of salt stress on morphological traits and electrophoresis pattern of proteins in recombinant inbred lines population of oilseed sunflower derived from PAC2 × RHA266 cross

IntroductionSalinity is one of the main abiotic stresses, especially in arid and semiarid conditions, which affects plant growth and thereby reduces seed yield. Materials and methodsIn the first part of this study, the morphological changes in 98 recombinant inbred lines population of oilseed sunflower derived from the cross of PAC2 × RHA266 were investigated in a complete block design with 3 replications under normal and 6 dS/m of salinity stress conditions. In both conditions, after flowering stage the characteristics including, grain yield per plant, 100 seeds weight, leaf number, stem diameter, plant height, capitol diameter, leaf length, leaf width, petiole length, capitol dried weight, date to flowering were measured. The relationship between grain yield and other morphological characteristics were investigated by simple correlation and stepwise regression analyses. Cluster analysis was used for grouping the genotypes based on all studied morphological characteristics in each one of normal and salinity conditions. Based on the results of the first part of work, two salt tolerant and sensitive lines (respectively C86 and C64 lines) were selected and planted at different salinity levels (0, 2, 4, 6 and 8 dS/m) conditions and their protein electrophoresis patterns were investigated using SDSPAGE. Results and discussionBased on the results of analysis of variance, salinity × genotype interaction effect was significant on all studied traits except for plant height, which indicated that the reaction of lines was different depending on different environmental conditions. Comparison of mean of lines in normal and salt stressed conditions indicated that the average of lines under salinity stress conditions decreased compared to normal one. However, the percentage of reduction is different depending on the traits. Heritability of traits varied between 0.07 for width of leaf to 0.50 for leaf number and day to flowering in normal conditions and in salinity stress conditions it varied between 0.09 for petiole length to 0.48 for weight 100 seeds and day to flowering. Based on stepwise regression analysis, the head diameter and 100 seeds weight were entered in the model and explained some part of yield variation in both salinity and normal conditions. So, selecting for these traits will improve grain yield in both conditions. In grouping of lines by using the minimum variance method (Ward method), all genotypes were grouped in 3 clusters in each of the environmental conditions. Under normal conditions, 49, 29 and 12 genotypes were grouped in the first, second and third clusters, respectively, and under salinity stress conditions, 42, 37 and 14 genotypes were placed in the corresponding groups. Based on the results of molecular experiment, different electrophoretic patterns for C86 and C64 lines were observed at different levels of salt stress, indicating a different reaction of lines to salt stress. ConclusionsThe highest coefficient of phenotypic variations was observed for grain yield, petiole length, leaf width, 100 seeds weight and head dried weight in both normal and salinity stress conditions which indicated their determinant roles in the development of phenotypic variation. In this study, traits such as capitul diameter and 100 seed weight due to high genetic variation, positive correlation and high direct effect on grain yield and moderate heritability, are suggested as desirable traits for selection of promising genotypes. In the second part of the study, based on the results, different electrophoretic patterns for C86 and C64 lines were observed at different levels of salt stress, indicating a different response of the genotypes to salinity stress.