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 × 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 × cultivar and tillage × seeding rate × 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 split‐plot arrangement in southwestern North Dakota during 1995–1998. Tillage × cultivar, seeding rate × cultivar, and tillage × seeding rate × 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.