LAUSR

Oat has been gaining renewed interest due to its role in human healthy diet. A field study was conducted across three diverse locations in Canada to determine N and P uptake, agronomic traits and yield performance of 10–12 cultivars under four fertilizer N rates. Our data showed that ‘SA060123’ and ‘OA1331-5’ were the highest-yielding cultivars, and ‘Dieter’ and ‘Morrison’ the lowest, across sites-years. Yield components were altered to adapt to soil-environmental conditions, specifically, panicles m−2 mostly accounted for yield variation at Melfort, seeds panicle−1 and 1000-seed weight at Normandin, and lodging index was an additional yield-determining factor at Ottawa. It was noted that severe crop lodging that occurred mainly at Ottawa, was logically associated with greater accumulation of straw N and plant biomass under high N supply conditions, and that crop lodging displayed a strong correlation with straw P content. Relationship of lodging index and straw P was best-fit into a split-line model with a change-point of 13.6 kg P ha−1, below which lodging rarely occurred. We speculate that high straw P content, induced by external N supply, may have exhibited similar behavior as N in weakening the strength of stem base and anchorage system, leading to crop lodging. This study also demonstrated an interactive genotype-by-environment effect on all traits except for the seed number panicle−1. Multidimensional preference analysis revealed the best performance of ‘SA060123’ for outstanding yield and 'Minstrel' for harvest index, respectively.