اثر محدودیت منابع فتوسنتزی بر عملکرد دانه و سایر خصوصیات زراعی ارقام و لاین‌های پیشرفته جو تحت شرایط کم‌آبی

به‌منظور بررسی اثر محدودیت منابع فتوسنتزی و تنش‌کم آبی بر عملکرد دانه و سایر خصوصیات زراعی ارقام و لاین‌های پیشرفته جو آزمایشی در سال‌های زراعی 94-1393 و 95-1394 در ایستگاه تحقیقات کشاورزی و منابع طبیعی میاندوآب انجام شد. در این تحقیق 12 رقم و لاین جو در پنج تیمار محدودیت منبع (شاهد (بدون محدودیت)، حذف برگ‌‌های زیر برگ پرچم، برگ پرچم، نصف سنبله و پوشش سنبله) در دو شرایط آبیاری نرمال و تنش کم آبی با سه تکرار ارزیابی شدند. مقایسه میانگین تیمارهای اثر متقابل ژنوتیپ در محدودیت منبع نشان داد اغلب ژنوتیپ‌های مورد بررسی در شرایط آبیاری نرمال، کمترین عملکرد دانه را در تیمارهای محدودیت حذف برگ پرچم، حدف نصف سنبله و پوشش سنبله نشان دادند، در حالی‌که تحت شرایط تنش کم‌آبی کمترین عمکرد دانه در ژنوتیپ‌های مورد بررسی تحت تیمارهای محدودیت حذف برگ پرچم و پوشش سنبله ثبت شد. در شرایط آبیاری نرمال تحت تیمار شاهد و حذف زیر برگ پرچم ژنوتیپ‌های شماره10، 2، 3، 4، 5، 6، 7، 8 و 12 از بالاترین عملکرد دانه برخوردار بودند و بین آنها اختلاف معنی‌دار وجود نداشت؛ تحت شرایط تنش کم‌آبی در تیمار شاهد کلیه ژنوتیپ ها به غیر از ژنوتیپ شماره 11 و در تیمار حذف زیر برگ پرچم کلیه ژنوتیپ‌ها به غیر از دو ژنوتیپ شماره 2 و 11 از عملکرد بالاتری در مقایسه با ژنوتیپ‌های دیگر برخوردار بودند. تحت شرایط آبیاری نرمال و تنش کم‌آبی در ژنوتیپ شماره 3، اختلاف معنی‌داری بین تیمار شاهد و تیمارهای محدودیت منابع حذف زیر برگ پرچم، حذف برگ پرچم و حذف نصف سنبله دیده نشد. در این مطالعه لاین‌های پیشرفته مورد بررسی برتری معنی‌داری نسبت به ارقام آزاد شده جو از نظر عملکرد دانه و سایر خصوصیات مورد بررسی نشان ندادند.

Effect of photosynthetic resource restriction on grain yield and other agronomic characteristics of cultivars and advanced barley lines under water deficit conditions

IntroductionBarley (Hordeum vulgare L.) is a widely cultivated cereal crop in many rainfed areas in the Mediterranean region where drought is considered the main yieldlimiting factor. In such marginal lands, yield losses are associated with drought conditions resulting from low and inconsistent precipitation during the whole plant growth cycle, either early in the fall or winter (initial drought conditions) or late during spring (terminal drought). Drought stress reduces grain yield of barley by negatively affecting the yield components i.e., number of plants per unit area, number of spikes and grains per plant or unit area and single grain weight, which are determined at different stages of plant development. Materials and methodsIn order to investigate the effect of sources limitation on yield and physiological characteristics in barley cultivars and advanced lines in various environmental conditions, an experiment was done in the Agricultural and Natural Resources Research Station of Miandoab in cropping 20162017. In this study, 12 varieties and lines of barley were evaluated in five sources limitation treatments including control (without limitation), leaf removal under flag leaf, flag leaf removal, half spike removal and spike coating in normal irrigation and water deficit conditions were evaluated in a randomized complete block design with three replications. In this study spike weight, leaf weight, peduncle weight, internode weight, seed number per spike, total plant weight and single plant yield were measured. Analysis of variance was performed using the SAS9.4 and SPSS programs. Result and discussionThe results of the combined analysis of variance showed that the effect of year on leaf weight and seed yield was significant at the level of 0.01. There was a significant difference between irrigation levels on all studied traits at the level of 0.01, the interaction effect of year in irrigation was also significant on all traits except total plant weight at the level of 0.01 probability. The effect of resource constraint, irrigation on resource constraint, genotype and the interaction of genotype on resource constraint were significant on all studied traits at the level of 0.01 probability. The interaction effect of year on resource constraint on leaf weight, peduncle weight, number of seeds per spike and seed weight was significant at 0.01 probability level. The interaction effect of year on genotype on total plant weight and number of seeds per spike was also significant. The interaction effect of irrigation in genotype was also significant on all traits at 0.01 probability level. Finally, the triple interaction of irrigation in source restriction in genotype on leaf weight and total plant weight was significant at the level of 0.01 and the number of seeds per spike and grain yield at the level of 0.05 probability was significant. Comparison of the mean of genotype with source restriction interaction treatments showed that most of the studied genotypes under normal irrigation conditions showed the lowest grain yield in treatments of flag leaf removal restriction, half spike target and spike cover, while under water deficit stress conditions, the lowest grain yield was recorded in the studied genotypes under the treatments of flag leaf removal and spike cover. Under normal irrigation conditions under control and removal under the flag leaf, genotypes No. 10, 2, 3, 4, 5, 6, 7, 8 and 12 had the highest grain yield and there was no significant difference between them. Under water deficit stress conditions, in the control treatment, all genotypes except genotype No. 11 and in flag removal treatment, all genotypes, except for genotypes No. 2 and 11, had higher yields compared to genotypes. Under normal irrigation conditions and Waterdeficit stress in genotype 3, there was no significant difference between control treatment and resource limitation treatments of remove below the flag leaf, flag leaf removal and half spike