Introgression Mapping of Genes for Winter Hardiness and Frost Tolerance Transferred from Festuca arundinacea into Lolium multiflorum

• Published in: The Journal of heredity 2007-07, Vol.98 (4), p.311-316
• Main Authors: Kosmala, A, Zwierzykowski, Z, Zwierzykowska, E, Łuczak, M, Rapacz, M, Gąsior, D, Humphreys, MW
• Format: Article
• Language: English
• Subjects: Adaptation, Biological - genetics; Botany; Breeding - methods; Chromosome Mapping; Cold; Festuca - genetics; Festuca arundinacea; Festuca pratensis; Gene Transfer Techniques; Genomics; Genotype; Hybridization; In Situ Hybridization, Fluorescence; Lolium - genetics; Lolium multiflorum; Molecular biology; Plants, Genetically Modified; Seasons
• ISSN: 0022-1503; 1465-7333
• DOI: 10.1093/jhered/esm047

Genes for winter hardiness and frost tolerance were introgressed from Festuca arundinacea into winter-sensitive Lolium multiflorum. Two partly fertile, pentaploid (2n = 5x = 35) F1 hybrids F. arundinacea (2n = 6x = 42) × L. multiflorum (2n = 4x = 28) were generated and backcrossed twice onto L. multiflorum (2x). The backcross 1 (BC1) and backcross 2 (BC2) plants were preselected for high vigor and good fertility, and subsequently, a total of 83 BC2 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 BC2 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 BC2 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 BC2 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.