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Divergent selection for single and multiple shoot tillering in big bluestem and switchgrass seedlings
Selecting seedling morphological traits may affect seedling vigor, stand establishment, and mature plant characteristics. Objectives of this research were to determine (1) the heritability of seedling tiller number and shoot weight in big bluestem (Andropogon gerardii Vitman) and switchgrass (Panicum virgatum L.) seedlings 6 to 8 weeks after planting, (2) the change in seedling tiller number and fresh shoot weight following two cycles of divergent selection for seedling tiller number while selecting for high shoot weight in big bluestem and switchgrass, (3) the effect of seedling tiller number on seedling morphological development and growth, and (4) the effect of seedling tiller number on mature plant characteristics and leaf elongation rate. ^ Results of these experiments demonstrated that seedling tiller number in big bluestem and switchgrass is moderately heritable (0.23 to 0.26) and that positive and negative changes in seedling tiller number were made by divergent selection. Seedling tiller number had no effect on seedling root growth and development, or stand establishment. Plant types derived from single tiller seedlings had a greater leaf elongation rate than plant types derived from multiple tiller seedlings. Plant characteristics, like plant height, leaf width, leaf length, and yield per tiller were greater for mature plants derived from single tiller seedlings. Number of tillers per plant was greater for mature plants derived from multiple tiller seedlings, but herbage yield of space-planted plants was not different for mature plants derived from seedlings differing in tiller number. Prior research has shown that high yield per tiller genotypes planted in swards have higher herbage yields than low yield per tiller genotypes, thus seedling tiller number in big bluestem and switchgrass should be a useful trait for changing mature plant morphology and improving herbage yield of these grasses. ^
Smart, Alexander John, "Divergent selection for single and multiple shoot tillering in big bluestem and switchgrass seedlings" (2001). ETD collection for University of Nebraska - Lincoln. AAI3016325.