Progress towards marker-assisted selection in forages

Abstract

In developing marker-assisted selection (MAS) for herbage yield and persistence traits in forages, traitlinked markers were tested in elite breeding populations of complex parentage, to identify population-specific marker:trait associations. The effectiveness of these were subsequently evaluated in progeny generated by MAS. In white clover (Trifolium repens), markers detected significant (P<0.005) within-population differences in node number, a trait contributing to plant persistence. Progeny carrying beneficial marker variants exhibited a 19% increase in node number compared to those lacking these markers. In perennial ryegrass (Lolium perenne), a single marker detected a herbage yield differential of up to 23% within the populations tested, and progeny from divergent MAS exhibited a similar performance difference. These findings show that traitlinked markers can be used to manipulate quantitative traits in elite breeding populations of forage species and may subsequently contribute to development of improved cultivars. A next generation of marker technology will support expansion from single locus selection approaches to genomic selection, applied directly in breeding populations, offering enhanced contribution to genetic gain. This proof of concept for MAS for yield and persistence traits in forage breeding is an important step toward acceleration of genetic gain in forages, underpinning the ongoing competitiveness of New Zealand's pastoral sector. Keywords: herbage yield, persistence, quantitative trait locus, simple sequence repeat, plant breeding