Genomic constitution of Festulolium cultivars released in the Czech Republic

Kopecký, David; Lukaszewski, A.J.; Doležel, Jaroslav
PLANT BREEDING 124: 454-458, 2005

Keywords: Festulolium; chromosome translocations; GISH
Abstract: Genomic in situ hybridization (GISH) was used to characterize the chromosome constitutions of individual plants from a set of tetraploid and hexaploid cultivars of Festulolium developed and released in the Czech Republic from hybrids of Lolium multiflorum with Festuca pra-tensis and F. arundinacea. A simplified GISH protocol readily discriminated parental geno-mes in the hybrids and facilitated the screening of large numbers of plants per accession. The contribution of parental genomes in the cultivars tested ranged from predominance of chroma-tin from one of the parents to a more balanced contribution from both parents. However, in none of the cultivars were equal proportions of chromatin from both parents present. The par-ental contribution to the hybrids was both in the form of complete chromosomes or as chro-mosome translocations. In hexaploid cultivars from (L. multiflorum × F. arundinacea) × F. arundinacea hybrids the average numbers of complete L. multiflorum chromosomes ranged from 4.95 to 7.5 and the numbers of translocations from 6.33 to 10.21. Two tetraploid culti-vars from (L. multiflorum × F. arundinacea) × L. multiflorum hybrids showed a strong preva-lence of L. multiflorum chromatin and intergeneric translocations were rare. In the tetraploid cultivar „Perun“ of the L. multiflorum × F. pratensis hybrid there were 11.7 chromosomes of L. multiflorum and 14.7 recombined chromosomes on average. Reasons for the domination of one of the parental genomes in hybrid cultivars are not clear and are only partially explained by breeding history. Recombination rates of individual genomes in hybrids involving F. arundinacea were evaluated in double hybridization experiments. The results indicated a strong affinity of the L. multiflorum genome for the F. pratensis genome present in F. arundi-nacea and little affinity for the F. glaucescens genome. This suggests that introgressions from F. arundinacea into L. multiflorum are primarily limited to the F. pratensis genome which can be more readily accessed in L. multiflorum × F. pratensis hybrids.
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IEB authors: Jaroslav Doležel, David Kopecky