Use of SSR Markers to Increase Forage Yield in Timoty (Phleum pratense L.)

Molecular markers may provide a tool to overcome the forage yield plateau in timothy (Phleum pratense L.) breeding. The objective of this study is a proposal for reciprocal recurrent selection (RRS) scheme with clone and strain synthesis (CSS) development using molecular markers to increase forage yields. This study was conducted to examine the relative contributions of general combining ability (GCA) and specific combining ability (SCA) to forage yield in CSS breeding scheme by predicting yields of first synthetic (Syn1) generation and second synthetic (Syn2) generation with molecular marker and field evaluation data. Here we discussed feasible RRS schemes using genetic diversity based on simple sequence repeat (SSR) marker polymorphism with selection simulations. The selection simulations of three patterns combined procedures of top-cross or polycross progeny tests were performed on the assumption that only two heterotic groups were identifiable by genetic diversity, and that an initial pollen parental strain was not improved in selection schemes. Among the three patterns, the RRS scheme, which established top-cross progeny tests in one group and polycross progeny tests in the another group, showed approximately twice the genetic gains (10.3 % per decade) for yields as much as that in half-sib selection with avoiding loss of accumulating additive effect.