NOVEL DIPLOIDS FOLLOWING CHROMOSOME ELIMINATION AND SOMATIC RECOMBINATION IN LOLIUM-MULTIFLORUM X FESTUCA-ARUNDINACEA HYBRIDS

Crosses were made between diploid Lolium multiflorum (2n = 2x = 14) an d hexaploid Festuca arundinacea (2n = 6x = 42) in order to produce new forage hybrids. The F-1 were treated with colchicine to double the ch romosome number and to restore fertility in the amphidiploids (2n = 8x = 56). Chromosome counting in fertile hybrids revealed some unexpecte d diploid plants (2n = 14), as well as the expected amphiploids with 2 n = 56. The phenotype of the diploids showed Festuca-like inflorescenc es which indicated they were not selfs of the L. multiflorum parent. C hromosome painting with a L. multiflorum genomic DNA probe showed the diploid complements to be recombinant and to carry some whole chromoso mes, and some chromosome segments of L. multiflorum together with othe r chromosome parts which originated from the F. arundinacea genome. Me iotic behaviour of the diploids was regular, with seven bivalents. The results are discussed in terms of the segregation and recombination o f different genomic components in the F-1 hybrids during diploidizatio n.