Yield Physiology of a Semidwarf and Tall Oat Cultivar

Abstract

Oat (Avena sativa L.) production has increased dramatically in the eastern Canadian prairies. The introduction of semidwarf oat cultivars to this region has resulted in the need for research regarding how a semidwarf oat performs relative to conventional tall oat cultivars. Split-split plot experiments were conducted at three site-years during 1999 and 2000 in Manitoba to examine cultivar responses of 'AC Ronald', a short-stature oat, and 'Triple Crown', a tall oat, under different crop rotations (grain legume or oilseed as a previous crop) and N fertilizer rates. Triple Crown had greater (P < 0.05) dry matter production than AC Ronald at anthesis (two of three sites) and maturity (one of three sites). At two of three sites, Triple Crown also displayed higher (P < 0.05) early season plant N uptake than AC Ronald, and Triple Crown always had higher (P < 0.05) kernel weight. However, averaged across sites, AC Ronald yielded 433 kg ha -1 greater (P < 0.05) than Triple Crown. Higher yield for the short-statured cultivar was attributed to greater (P < 0.05) panicle and kernel densities, and better assimilate partitioning (i.e., higher harvest index). Both cultivars were susceptible to lodging; however, Ha significant cultivar x site interaction indicated that under some conditions, AC Ronald experienced less lodging than Triple Crown. No significant cultivar effect was observed for evapotranspiration (ET) or water use efficiency (WUE). Both oat cultivars responded similarly to crop rotation and N fertilizer rate. While the grain yield advantage of AC Ronald appeared stable across treatment environments tested here, some differential cultivar responses for kernels per panicle and lodging resistance across sites were observed. This research supports an expansion of semidwarf oat production in the eastern Canadian prairies.