The effect of drought stress and plant density on yield and yield components of irrigated wheat cultivars in the temperate region of Lorestan province

This study was conducted to investigate the effect of drought stress and plant density on yield and some yield components of wheat cultivars in Boroujerd Agricultural Research Station in 2019-2020. The experiment was performed as a split factorial in a randomized complete block design. The main plots belonged to drought stress treatments (at three levels of control, irrigation to flowering, and irrigation to grain filling). The sub-plots consisted of plant density treatments (300, 400, 500, and 600 plants m−2) and cultivars (Mihan and Baharan). The results showed that drought stress, density, and cultivar treatments influenced grain yield components, and the interaction of stress ×plant density significantly affected plant height and spike length. The interaction of cultivar × stress significantly influenced plant height, 1000-seed weight, grain yield, and flag leaf area index. The interaction of cultivar × density was also significant on plant height, spike length, and internode diameter. The highest plant height (87 cm) was obtained in the treatment of 600 plants/m2 without applying drought stress. The highest plant height among all treatments belonged to the Baharan cultivar cultivated at a density of 600 plants/m2. The spike length was higher in full irrigation treatment and at the level of 500 plants/m2 than in the other experimental treatments. The dry weights of flag leaves were 2.8 and 3 g in Mihan and Baharan cultivars, respectively. The highest 1000-seed weight (43.7 g) in the Mihan cultivar at the level of complete irrigation treatment increased by about 12% compared to that in irrigation....