RFLP AND CYTOGENETIC ANALYSES OF HYBRIDS BETWEEN FESTUCA-MAIREI AND LOLIUM-PERENNE

Information is lacking on the genomic relationships between Festuca mairei St. Yves and Lolium perenne L. Tetraploid (2n = 4x = 28, where x = the related affinity of the more closely related genome) F. mairei, diploid (2n = 2x = 14) L. perenne, and their intergeneric hybrids were used to determine their genomic relationships based on RFLP patterns of parental species and meiotic chromosome pairing of the hybrids. Among 41 heterologous probes randomly chosen from a F. arundinacea PstI-genomic library, 70 and 87% hybridized to L. perenne and F. mairei, respectively. However, different restriction patterns occurred between the two species, indicating their distant relationship. Eighteen triploid (3x) and two tetraploid hybrids between F. mairei and L. perenne were obtained. The formation of 4x hybrids from 4x x 2x crosses confirmed that L. perenne is a 2n pollen producer. Triploid and tetraploid hybrids had high levels of chromosome pairing with an average of 6.60 and 11.62 bivalents, respectively. Optimization analysis of meioses in 3x and 4x hybrids strongly confirmed that F. mairei is a fragmented allotetraploid with MMM'M' genomes. The M genome is closely related to the M' genome. The L genome of L. perenne is, however, distantly related to the M and M' genomes.