Inheritance of Secondary Morphological Traits for Among‐and‐Within‐Family Selection in Upland Tetraploid Switchgrass

Abstract

ABSTRACTMajor 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 (0.41) was estimated for plant height but was greater for selection of increased height. Heritability for tiller count was low overall (0.06), with greater values observed for reduced tillering selections. Flowering date was estimated to have high heritability (0.75) overall in both selection directions. Plant height and flowering date both appear heritable on a spaced‐plant basis and may 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 the timing of selections.