Tillage and seeding rate effects on wheat cultivars: I. Grain production

Tillage is declining in wheat production systems in the Great Plains. Our objective was to determine if a tillage X cultivar interaction occurred for grain yield, protein concentration, kernel weight, and test weight for hard red spring wheat (Triticum aestivum L. emend. Thell.) in a wheat-fallow monoculture. We also wanted to know if seeding rate X cultivar and tillage X seeding rate X cultivar interactions occurred for these grain traits. The cultivars AC Minto, Amidon, Bergen, Grandin, and Norm were seeded at 123, 247, and 371 live kernels m(-2) in conventional-till (CONT), reduced-till (RT), and no-till (NT) systems in a randomized complete block with a split splitplot arrangement in southwestern North Dakota during 1995-1998. Tillage X cultivar, seeding rate X cultivar, and tillage X seeding rate X cultivar interactions did not occur for any grain trait (P > 0.05). Grain yield, protein concentration, kernel weight, and test weight were unaffected by tillage system. A positive quadratic response in grain yield occurred as the seeding rate was increased. Grain test weight increased from 577 to 586 g m(-3) as the seeding rate increased from 123 to 371 kernels m-2, but grain protein concentration and kernel weight were unaffected. Grain yield ranged from 2473 to 3063 kg ha(-1), crude protein from 141 to 154 g kg(-1), kernel weight from 30 to 32 g (1000 kernels)(-1), and test weight from 572 to 590 g m(-3) among the five cultivars. Results of this study suggest that cultivar recommendations under CONT can be extended to RT and NT systems in a wheat-fallow monoculture.