Assessment of resistance to lodging of landrace and improved cultivars in foxtail millet

摘要

Lodging results in serious yield and quality reductions in foxtail millet (Setaria italica). Among summer crops, foxtail millet is a high density and soft stalked crop that is prone to lodging. Field selection for lodging resistance is difficult because the occurrence of lodging depends on the environmental conditions. A practical method for the evaluation of lodging is not available for foxtail millet, so an understanding of lodging-associated traits and identifying a suitable method to assess lodging are essential to select for lodging resistance and to predict the risk of lodging in a cultivar. In the present study, six stem and root traits associated with lodging was measured in the field and lodging coefficients were determined to evaluate lodging resistance in landrace and improved cultivars. Based on the results of correlation analysis, lodging coefficient is a suitable indicator for field selection for lodging resistance in both classes of cultivars tested for breeding purpose. Statistical analyses demonstrated that lodging was associated with stem quality rather than plant height and internode length at the stem base. The most important trait that directly impacted on lodging coefficient was mechanical strength of the stem and plant height in the landraces, while the weights of the above- and under-ground tissues, in combination with mechanical strength of the stem, were the most important contributors to lodging coefficient in the improved cultivars.