Application of AFLP and GISH Techniques for Identification of Festuca Chromosome Segments Conferring Winter Hardiness in a Lolium perenne × Festuca pratensis Population

Abstract

Diploid BC1, BC2 and BC3 introgression lines derived from the amphiploid Lolium perenne × Festuca pratensis cv. Prior were scored for freezing tolerance and analysed using AFLP markers and GISH in order to associate molecular markers to introgressed Festuca segments. The freezing tests showed highly significant differences between clones of the introgression lines. Two introgression lines were more frost tolerant than the diploid Lolium-control cultivars. Thirteen AFLP-primer combinations were tested. It was not possible to identify single markers that were present in the most freezing tolerant plants, and absent in the most susceptible ones. The GISH analyses of 20 diploid PriorBC1-plants with Lolium-morphology showed that 3 genotypes had no visible Festuca-segments, while the others had 1–5 segments of different sizes. Analyses of a Prior-BC3 population showed that introgression in the satellite region of chromosome 3 seem to confer enhanced frost tolerance to Lolium. Winter hardiness and freezing tolerance are quantitative traits governed by genes on different chromosomes, and combinations of AFLP markers tagging different chromosomal regions may be used together to select superior genotypes during introgression. AFLP markers most frequently present in plants with the highest freezing tolerance, and absent in plants with inferior freezing tolerance, were therefore chosen and associated with winter hardiness and with the presence of Festuca introgressions. These markers may be useful in marker-assisted breeding programmes.Key wordsFestucaLoliumfreezing-toleranceAFLPGISH