Abstract: In order to clarify the regulation mechanism of stem lodging under different densities and irrigation schedules，an experiment was conducted in field． The experiment included 5 irrigation schedules such as no irrigation( W0), irrigation once at jointing(W1j) or at booting(W1b), irrigation twice at jointing and booting(W2),and irrigation three times at jointing，booting and grain-filling(W3),and 3 planting densities such as 180(D1),300 (D2) and 450 seedlings per square meter(D3). The results indicated that irrigation had a significant effect on stem traits and lodging index． Plant height， stem gravity height and grain yield presented a low-high-low variation trend with the increasing of irrigation times． Dry weight of stem and basal internodes per centimeter，dry matter output of stem and basal intermodes per centimeter， stem diameter and stem mechanical strength decreased significantly with the increasing of irrigation times． Stem indexes of W2 such as plant height，stem diameter，stem mechanical strength，dry weight of stem and basal internodes per centimeter and grain yield were superior to other irrigation schedules． At the same time，plant height and associated gravity height became increased significantly． With the increasing of densities． Stem diameter， stem mechanical strength，dry weight of stem and basal internodes per centimeter， dry matter output of stem and basal internodes per cetimeter decreased significantly with the increasing of densities． And grain yield of D2 was higher， followed by D3 and D1． It indicated that spring irrigations applied at jointing and booting stage(W2),and combining with 300 seedlings per square meter could improve stem quality， lodging resistance and grain yield effectively．

Key words: Irrigation schedules, Planting densities, Stem traits, Lodging, Winter wheat

CLC Number: 

• S275