LAUSR

Abstract Developing an appropriate strategy to increase oat yield potential to meet the increasing market demand and overall returns is urgently needed. Crop lodging is the main constraint for improving oat yields. The objectives of this study were aimed to evaluate the effect of leaf posture on crop lodging resistance and lodging related traits, yield performance and their responses to plant populations. Four genotypes with similar yield potential, but differing substantially in leaf architecture, i.e., erect–leaf (E) vs. prostrate–leaf type (P), were tested under three plant population conditions. The results showed that with increasing plant densities from 200 to 600 plants m–2, resistance to stem lodging, resistance to root lodging, and grain yield were decreased, respectively by 21.9%, 14.9% and 6.8% for the P cultivars, but increased by 11.5%, 28.7%, and 3.2%, for E cultivars, averaged across both years. It implied that erect–leaf posture could promote crop resistance to lodging, especially under high plant population condition. Oat plants were more prone to anchorage failure than stem buckling, which was illustrated by the quantitative “safety factor” that was closely related to the visual lodging scores based on field investigation (R2 = 0.56* in 2017). Thus, root lodging should be targeted as the priority criteria in oat breeding for selecting more rigid root system. Taken together, two important attributes of the plant ideotype, i.e., erect–leaf architecture and rigid root system, could be recommended to plant breeders in selecting oat cultivars with improved high–yielding potential and strong lodging resistance.