Use of Molecular Marker Information in the Construction of Polycrosses to Enhance Yield in a Lolium perenne Breeding Programme

Abstract

The aim of this study is to evaluate the use of molecular marker information in the construction of polycrosses to enhance yield in a diploid Lolium perenne breeding programme. The starting material used for this study consisted of 30 diploid late perennial ryegrass plants selected from advanced breeding material. Pairwise Jaccard similarities among these 30 genotypes were determined on the basis of 559 AFLP markers. Jaccard similarities varied between 0.334 and 0.686, with a mean value of 0.467. Nine polycrosses (PC) of four parental plants with different levels of genetic similarity were composed in 2007: three wide PC with low Jaccard similarities between parental plants (0.334–0.447), three medium PC with intermediate Jaccard similarities (0.405–0.540) and three narrow PC with high Jaccard similarities (0.523–0.686). Some parental plants were used in more than one polycross. The seed was harvested in 2008 and a progeny evaluation trial was sown in April 2009. The dry matter yield was measured in the growing season of 2010 and will be measured in 2011. Progenies from medium and wide polycrosses were on average significantly higher yielding than the progenies from the narrow polycrosses (yield increase of 4.2–6.1 % respectively) in 2010. There was a trend but not significant that the yield of the progenies of the same parental plant from wider polycrosses was higher compared to progenies from narrow polycrosses. We may conclude that the application of molecular markers to select genetically diverse polycross parents can result in an average yield increase.