‘Chromosome painting’ by fluorescent in situ hybridization (FISH) in hybrids and introgressions of Lolium and Festuca species

Abstract

Fluorescent in situ hybridization (FISH) was used to characterize genomic constitution and chromosome rearrangements in amphiploid ×Festulolium braunii cultivars ‘Punia’ and ‘Rakopan’ (winter-persistent and random plants), and Lolium perenne × [Festuca pratensis] introgression lines BC2-2 (freezingtolerant and non-tolerant) together with triploid parental plants and the previous generations BC1 and BC2. The presence of F. pratensis, L. Perenne and ribosomal DNA (rDNA) has been evaluated. Hybridization patterns in ‘Punia’ and ‘Rakopan’ revealed more L. perenne chromosomes in the winterhardy than in random plants. In intogression lines, frost-resistant plants had a higher number of introgressed F. pratensis DNA fragments and more rDNA sites than non-resistant ones. In BC2-2 plants, F. pratensis introgressions were very small and in most of the cases fragments were found next to rDNA sites. Keywords: FISH, GISH, Festuca, Lolium, Festulolium, species introgression, genome recombination, rDNA