نوع مقاله : مقاله پژوهشی
نویسندگان
گروه زراعت و اصلاح نباتات دانشکدگان کشاورزی و منابع طبیعی دانشگاه تهران، کرج، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Drought, a major factor limiting wheat yield worldwide, affects sink strength by disrupting key physiological processes such as endosperm cell division and grain filling. This study investigated the impact of drought stress on sink capacity and grain filling, focusing on endosperm cell division characteristics during the 2020–2021 growing season in the greenhouse of the Department of Agronomy and Plant Breeding at the University of Tehran. Two wheat cultivars differing in drought sensitivity (Hamoon: resistant; Shoosh: sensitive) were evaluated under two moisture regimes: well-watered (70% field capacity) and drought-stressed (50% field capacity). The results indicated that drought stress caused a 31.70% reduction in grain yield in Shoosh and a 25.34% reduction in Hamoon. It also significantly decreased final grain weight, grain-filling rate, and the active grain-filling period in both cultivars. The decline in the final number of endosperm cells (41.66% in Shoosh and 29.41% in Hamoon), along with a shortened cell division period (by approximately 4–5 days), directly reduced sink strength and grain-filling rate. Indeed, the reduction in cell division disrupted assimilate mobilizatin to the grain and underscored the critical role of this process in regulating the grain-filling rate. Overall, the greater stability of cellular activity in Hamoon contributed to better maintenance of sink strength and final yield under drought stress conditions. These findings emphasize the importance of selecting genotypes with strong cell division capacity under drought conditions.
کلیدواژهها [English]
)