Marker assisted polycross breeding to increase diversity and yield in perennial ryegrass (Lolium perenne L.)

Abstract

In this study, the application of molecular markers to optimise genetic diversity in a polycross breeding program of perennial ryegrass (Lolium perenne L.) was evaluated. The genetic diversity among 98 potential parental plants from three maturity groups (early, intermediate and late flowering) was investigated using amplified fragment length polymorphism (AFLP) markers. For each maturity group, two polycrosses of six parental plants with contrasting levels of genetic diversity were composed. Average genetic diversity among parents selected for narrow polycrosses was 36% lower than among parents selected for wide polycrosses. Diversity within first generation synthetic progenies (Syn1) was proportional to the diversity within the respective parental polycrosses. However, differences were less pronounced with Syn1 progenies from narrow polycrosses showing 16% reduced diversity when compared to Syn1 progenies from wide polycrosses. Multivariate analyses allowed for a clear separation of the six Syn1 progenies based on AFLP markers and demonstrated their genetic distinctness. Evaluation of dry matter yield, date of ear emergence and stem length of Syn1 and Syn2 progenies showed progenies from wide polycrosses to be constantly higher yielding when compared to progenies from narrow polycrosses. On the other hand, there was no significant difference in variability for the two morphological traits between progenies of narrow-and wide polycrosses. The results presented here provide evidence for an efficient application of molecular markers to select genetically diverse polycross parents which resulted in an average yield increase of 3.8%.

Implementation of Molecular Markers Diversity in Parental Selection of Alfalfa (Medicago SativaL.) Germplasm

“…in comparison with their parents characterised by large genetic distances, the progenies values of the number of stems (nS) and plant height (Ph) were greater with 10.84% to 30.29% (nS), and 8.01% to 22.01% (Ph) ( Table 4, Table 5). these results are consistent with the results obtained in research on different plant species (11,13,14,22,29) where significant positive associations between the genetic diversity of parental genotypes/ populations/germplasm and the yield of their single-cross progenies/breeding lines/hybrids were also reported. *,** significance at the probability level of 0.05 and 0.01, respectively in the group of combinations where parental components had a smaller genetic distance (similar germplasm), most derived F 1 progenies achieved lower values for the yield and other analysed traits comparing to their parents ( Table 2, Table 3, Table 4 and Table 5).…”

Applied Genetics and Genomics in Alfalfa Breeding

“…Markers could be useful simply by assessing genetic diversity in a set of potential parents and selecting the most genetically divergent group as parents of the next generation (or synthetic cultivar) [46,47,103]. In these experiments, synthetics developed based on diverse parents had improved yield.…”

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

“…The use of molecular marker information in the parental selection may optimise the parental combinations to maximize heterosis. According to Kölliker et al (2005) application of molecular markers to select genetically diverse polycross parents can result in an average yield increase. In this study molecular markers were used to compose polycrosses with different levels of genetic diversity.…”