|Price, David -|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 26, 2013
Publication Date: March 4, 2014
Citation: Price, D., Casler, M.D. 2014. Inheritance of secondary morphological traits for among-and-within-family selection in upland tetraploid switchgrass. Crop Science. 54:646-653. Interpretive Summary: Efforts to increase the rate of progress for increasing biomass yield of switchgrass are focusing on morphological traits related to yield, including flowering time, plant height, and number of stems. Research demonstrated that each of these traits has a positive heritability value, indicating that there is significant genetic variation that can be utilized in a breeding program. Because flowering time had a very high heritability value, results suggested that this trait be given the greatest emphasis to select the best plants within the best families. These results will be of direct value to switchgrass breeding programs with improvement in biomass yield as a major goal.
Technical Abstract: Major efforts are currently being undertaken to improve biomass yield in switchgrass. Among-and-within-family selection has been proposed as an efficient selection scheme to increase rates of genetic gain. The objectives of this study were to estimate the heritability of three yield-related traits (plant height, tiller count, and flowering date) and evaluate the suitability of those traits as within-family-selection criteria. Divergent selections of parents were made for each trait from an upland-tetraploid population developed for use in temperate North America. Progeny from these selections were used to estimate narrow-sense heritability by both parent-progeny regression and response to selection. Moderate heritability was estimated for plant height but was greater for selection of increased height. Heritability for tiller count was low overall, with greater values observed for reduced tillering selections. Flowering date was estimated to have high heritability overall in both selection directions. Plant height and flowering date both appear to be effective selection criteria for within-family selection. The relative value of among-and-within-family selection within a practical breeding program will vary depending on what selection criteria are used and timing of selections.