title: Introgression mapping of genes for winter hardiness and frost tolerance transferred from Festuca arundinacea into Lolium multiflorum.
abstract: Genes for winter hardiness and frost tolerance were introgressed from Festuca arundinacea into winter-sensitive Lolium multiflorum. Two partly fertile, pentaploid (2n = 5x = 35) F(1) hybrids F. arundinacea (2n = 6x = 42) x L. multiflorum (2n = 4x = 28) were generated and backcrossed twice onto L. multiflorum (2x). The backcross 1 (BC(1)) and backcross 2 (BC(2)) plants were preselected for high vigor and good fertility, and subsequently, a total of 83 BC(2) plants were selected for winter hardiness after 2 Polish winters and by simulated freezing tests. Genomic in situ hybridization (GISH) was performed on 6 winter-hardy plants selected after the first winter and shown to be significantly (P < 0.05) more frost tolerant than the L. multiflorum control. Among the analyzed BC(2) winter survivors, only diploid (2n = 2x = 14) plants were found. Five plants carried 13 intact L. multiflorum chromosomes and 1 L. multiflorum chromosome with a single introgressed F. arundinacea terminal chromosome segment. The sixth BC(2) winter survivor appeared to be Lolium without any Festuca introgression capable of detection by GISH. A combined GISH and fluorescence in situ hybridization analysis with rDNA probes of the most winter-hardy (after 2 winters) and frost-tolerant BC(2) plant revealed the location of an F. arundinacea introgression on the nonsatellite arm of L. multiflorum chromosome 2, the same chromosome location reported previously as a site for frost tolerance genes in the diploid and winter-hardy species Festuca pratensis.
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479 Poznań, Poland. akos@igr.poznan.pl
authors.forename: A
authors.initials: A
authors.lastname: Kosmala
authors.forename: Z
authors.initials: Z
authors.lastname: Zwierzykowski
authors.forename: E
authors.initials: E
authors.lastname: Zwierzykowska
authors.forename: M
authors.initials: M
authors.lastname: Luczak
authors.forename: M
authors.initials: M
authors.lastname: Rapacz
authors.forename: D
authors.initials: D
authors.lastname: Gasior
authors.forename: Mw
authors.initials: M
authors.lastname: Humphreys
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D001947:Breeding / Q000379:methods; D002874:Chromosome Mapping; D031751:Festuca / Q000235:genetics*; D018014:Gene Transfer Techniques; D005838:Genotype; D017404:In Situ Hybridization, Fluorescence; D008129:Lolium / Q000235:genetics*; D030821:Plants, Genetically Modified; D012621:Seasons