IDENTIFICATION OF PARENTAL AND RECOMBINED CHROMOSOMES IN HYBRID DERIVATIVES OF LOLIUM-MULTIFLORUM X FESTUCA-PRATENSIS BY GENOMIC IN-SITU HYBRIDIZATION

Genomic in situ hybridization (GISH) was used to identify Festuca chro matin in mitotic chromosomes of Lolium multiflorum (Lm)x Festuca prate nsis (Fp) hybrids and hybrid derivatives. In two inverse autoallotripI oids LmLmFp and LmFpFp, in situ hybridization was able to discriminate between the Lolium and Festuca chromosomes. In a third triploid hybri d produced by crossing an amphiploid of L. multiflorum x F. pratensis (2n=4x=28) with L. multiflorum (2n=2x=14), the technique identified ch romosomes with interspecific recombination. Also, in an introgressed l ine of L. multiflorum which was homozygous for the recessive sid (sene scence induced degradation) allele from F. pratensis, a pair of chromo some segments carrying the sid gene could be identified, indicating th e suitability of GISH in showing the presence and location of introgre ssed genes. By screening backcross progeny for the presence of critica l alien segments and the absence of other segments the reconstitution of the genome of the recipient species can be accelerated.