Temperature, planting depth, and genotype effects on seedling characteristics and seeding rate effects on agronomic and quality performance of winter wheat (Triticum aestivum L.)

Temperature levels, planting depths, and cultivars, affected seedling traits as expected. An increase in temperature from 12.8/12.8 to 20/20°C increased coleoptile length by 21 min implying that higher temperatures facilitated coleoptile elongation. An increase in planting depth from 2.5 to 7.5 an increased coleoptile length, shoot length, and fresh weight and decreased root length and germination % of the seedlings across cultivars. Cultivars had a wide range of responses in their mean performance for the seedling traits. Scout 66, Nekota, and Niobrara were considered to have good seedling vigor while Alliance, Arapahoe and Centura, were considered to have poor seedling vigor. Strong and significant positive correlation between coleoptile length and germination %, shoot length and fresh weight, and fresh weight and dry weight were observed. In summary, planting depths and cultivars had a greater impact on seedling traits than did our temperature levels. Planting depth and cultivars are controllable management factors; hence the optimum depth must be practiced for the appropriate cultivar. Coleoptile length is the trait that was most significantly affected by temperature regimes, planting depths and cultivars. It is the best predictor of seedling vigor and hence can be used as a selection criterion in the development of cultivars with vigorous seedlings. While numerous experiments have studied how seeding rates affect agronomic performance of wheat (Triticum aestivum L.) cultivars, there are no or very few experiments which have studied how seeding rates affect end use quality particularly of modern wheat cultivars. Twenty winter wheat cultivars, were evaluated to assess the effect of cultivar and seeding rate on agronomic and quality performance of wheat. Significant differences among environments, seeding rates, cultivars and some of their interactions were identified. Lower seeding rates decreased stand density, grain yield and thousand-kernel weight and caused l