Submitted to: Eucarpia Congress Plant Breeding Sustaining The Future
Publication Type: Abstract Only
Publication Acceptance Date: June 6, 2008
Publication Date: September 9, 2008
Citation: Casler, M.D. 2008. Optimizing Among-and-Within-Family Selection in Forage Crops [abstract]. Eucarpia Congress Plant Breeding Sustaining The Future. p. 341. Technical Abstract: Genetic gains in forage yield lag far behind the gains made in grain yield of cereal crops, partly due to the use of inefficient selection methods that make little use of additive genetic variance within half-sib or full-sib families. Theoretical expected gains show that among-and-within-family (AWF) selection is equal to or better than family selection under all circumstances provided the within-family selection criterion (X or Y) is heritable and has a positive genetic correlation with the desired trait (Y). AWF selection is favored over progeny-test selection by: (1) high heritability on an individual-plant basis (relative to heritability on a family-mean basis), (2) within-family selection intensity greater than among-family selection intensity, and (3) possibly a shorter cycle time (for some species and some breeding programs). Empirical studies on three perennial grasses demonstrated a positive genetic correlation between forage yield (Y) and survivorship (X), resulting in a significant improvement of AWF selection over family selection in two rhizomatous species.