Genetic tools for increased white clover seed production

Abstract

Genome maps and DNA markers allow plant breeders to decipher the genetic control of commercially vital quantitative traits. Discovery of the components of these genetic control networks will create opportunities to implement more efficient forage breeding systems. Gene mapping research strategies, using a combination of field trials and DNA-marker data, were used to discover quantitative trait loci (QTL) impacting seed production in white clover (Trifolium repens). Twelve QTL influencing seed yield (SY) or the two component factors inflorescence density (ID) and seed provisioning (SP) were detected using a full-sib gene mapping population in the 2002 trial at Lincoln, New Zealand. Three of these QTL also were detected in the 2003 trial, of which one for ID and one for SP harboured alleles that accounted for up to a 50% change in ID and SP trait value, respectively. Genetic tests for these two alleles were used in a marker-assisted selection (MAS) experiment to identify the plants in the gene mapping population with the highest commercial potential. This initial proof-ofconcept MAS design was successful in identifying the subpopulation with the highest SY value. Implementation of MAS designs will result in increased ability for plant improvement programmes to assure development of commercially successful forage cultivars. Keywords: marker-assisted selection, QTL, seed production, white clover