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P.M. Carr, R.D. Horsley, and W.W. Poland. 2003. Tillage and seeding rates effects on wheat cultivars II. Yield components. Crop Sci. 43:210-218.
Tillage is declining in dryland wheat production systems. Our objectives were to determine if tillage Í cultivar, seeding rate Í cultivar, and tillage Í seeding rate Í cultivar interactions occurred for the yield components of hard red spring wheat (Triticum aestivum L. emend. Thell.) in a wheat-fallow monoculture. The cultivars AC Minto', Amidon', Bergen', Grandin', and Norm' were seeded at 123, 247, and 371 kernels m-2 in conventional-till (CONT), reduced-till (RT), and no-till (NT) systems in a randomized complete block in a split-split plot arrangement during 1995-1998. Tillage Í cultivar and tillage Í seeding rate Í cultivar interactions did not occur for any yield component (P > 0.05). A seeding rate Í cultivar interaction occurred for both plant stand and tiller production, but the interaction resulted from a change in the magnitude of response and not in the ranking of cultivars to seeding rate adjustments for either yield component. Plant stand and the number of tillers plant-1 were unaffected by tillage systems, but the number of spike-bearing tillers increased from 411 m-2 under CONT to 457 m-2 under NT. Tillage systems did not affect the number of kernels spike-1 or kernel weight. More spike-bearing tillers m-2 occurred as the seeding rate increased, but there were fewer tillers plant-1 and a negative quadratic response in the number of kernels spike-1. Results of this study indicate that the ranking of contrasting hard red spring wheat cultivars for yield components is unchanged by reductions in tillage in a wheat-fallow monoculture.