Yield Physiology of a Semidwarf and Tall Oat Cultivar

Abstract

first registered semidwarf oat cultivar. The pedigree for AC Ronald includes Dumont 68, Robert, and OT207. Brown et al. (1980) developed the semidwarf oat OT207 the eastern Canadian prairies. The introduction of semidwarf oat cultiby selecting it from OT184 irradiated with fast neutrons. vars to this region has resulted in the need for research regarding how a semidwarf oat performs relative to conventional tall oat cultivars. Oat (Avena sativa L.) production has increased dramatically inDwarfing in OT207 is controlled by a single dominant Split-split plot experiments were conducted at three site-years during gene designated Dw6, which results in shorter internodes. and 2000 in Manitoba to examine cultivar responses of 'ACThe semidwarf character in cereals is associated with Ronald', a short-stature oat, and 'Triple Crown', a tall oat, under increased yield through increased panicle production different crop rotations (grain legume or oilseed as a previous crop) (Brinkman and Rho, 1984;Hamill, 2002), kernel proand N fertilizer rates. Triple Crown had greater (P Ͻ 0.05) dry matter duction (Anderson and McLean, 1989;Hamill, 2002), production than AC Ronald at anthesis (two of three sites) and matuharvest index (Pearman et al., 1978), and lodging resisrity (one of three sites). At two of three sites, Triple Crown also tance (Brown et al., 1980). displayed higher (P Ͻ 0.05) early season plant N uptake than AC Soil water availability is a major factor limiting cereal Ronald, and Triple Crown always had higher (P Ͻ 0.05) kernel weight. grain production in western Canada (DeJong and Step-However, averaged across sites, AC Ronald yielded 433 kg ha Ϫ1 greater (P Ͻ 0.05) than Triple Crown. Higher yield for the short-puhn, 1983). There has been no previous research comstatured cultivar was attributed to greater (P Ͻ 0.05) panicle and kernel paring the ET and WUE of semidwarf and tall oat densities, and better assimilate partitioning (i.e., higher harvest index). cultivars. In studies with wheat, Richards (1992) found Both cultivars were susceptible to lodging; however, Ha significant no differences in consumptive water use between tall cultivar ϫ site interaction indicated that under some conditions, AC and dwarf cultivars, though Ehdaie and Waines (1996) Ronald experienced less lodging than Triple Crown. No significant P.J. de Rocquigny, Manitoba Agriculture, Food and Rural Initiatives, following crops (Badaruddin and Meyer, 1990; Steven-Soils and Crops Branch, Carman, MB, Canada R0G 0J0; M.H. Entz son and van Kessel, 1996). and R.M. Gentile,

Spring Cereals: From Dynamic Ideotypes to Cultivars in Northern Latitudes

“…In oat, comparable Dw-genes have been incorporated into cultivars with nearly similar results as with wheat (de Rocquigny et al 2004). There are 20 dwarfing genes in wheat, out of which Rht1 and Rht2 are most widely used around the world, Rht8 and Rht9 have been occasionally used in European wheat varieties, Rht15, Rht16, Rht18, Rht19 and Rht20 have potential but are not currently used in breeding, Rht12 is dominant and Rht4, Rht6, Rht7, Rht11, Rht17 are recessive.…”

Soil water depletion by tall and semidwarf oat and wheat cultivars

“…Greater soil water depletion and biomass production may indicate that the conventional height oat performs better under excessive moisture conditions. Little lodging was observed at Winnipeg in 2000 (de Rocquigny et al 2004); however others (e.g., Brown et al 1980) observed that lodging may limit tall cultivar oat productivity under high moisture growing conditions. There were no significant interactions between cultivar and N rate or previous crop observed at any site-year, which indicates that the relative soil water depletion comparisons of the oat and wheat cultivars were stable across all N environments.…”

“…Soil tests the following year indicated that nitrate-N levels (0-120 cm) in the flax and pea rotations, respectively, were 127 and 193 kg ha -1 at Carman 1999, 83 and 174 kg ha -1 at Carman 2000, and 83 and 167 kg ha -1 at Winnipeg 2000. Across all 3 site-years the pea rotation contributed an average of 80 kg ha -1 greater soil nitrate-N than the flax rotation at the time of oat and wheat seeding (de Rocquigny et al 2004). …”

“…Treatment means were compared using a Fisher's protected least significant difference test at the P < 0.05 level. Oat yield, dry matter production and water use efficiency results from these trials have been published earlier (de Rocquigny et al 2004).…”

“…An explanation for greater water use by Triple Crown (the tall oat cultivar) at this site-year may be related to biomass production. The Winnipeg site-year was the only trial in which the short and tall oat cultivars differed in the amount of biomass produced, with Triple Crown having significantly greater dry matter production at maturity than AC Ronald (de Rocquigny et al 2004). Greater soil water depletion and biomass production may indicate that the conventional height oat performs better under excessive moisture conditions.…”