Marker-based parental selection to improve performance of orchadgrass polycross populations under water deficit environments

Abstract

Little is known about the application of parental molecular information to enhance the performance of synthetic populations of orchardgrass under water deficit environments. In this study, first generation progenies of four polycrossed groups constructed from a combination of several parental genotypes with contrasting levels of diversity (high and low phenotypic, high and low molecular) were assessed in a field trial for quantitative traits under normal and water stress conditions and in the laboratory for germination and seedling growth properties. To investigate genetic variation, the DNA from the selected genotypes were subjected to inter-simple sequence repeat and sequenced-related amplified polymorphism markers. The assessment of first generation showed a clear separation of the four progeny groups in both water environments indicating that the progeny performance depends on the level of diversity among the parental genotypes. Molecular distance was highly associated with progeny performances of all traits at both moisture conditions. Crosses between genetically distant parents led to significantly increased drought tolerance of progenies. Although significant associations between phenotypic diversity among polycross parents and progenies performance were found for some traits under normal conditions, no such relationship was observed under water stress conditions. The results indicated that the predictive ability of parental phenotypic distance was strongly affected by the target trait and moisture conditions. Superiority of first generation progeny from parents with high molecular diversity under both moisture conditions emphasizes the benefit of marker-assisted polycross breeding in orchardgrass.