ISOZYME AND QUANTITATIVE TRAITS POLYMORPHISMS IN EUROPEAN PROVENANCESOF PERENNIAL RYEGRASS (LOLIUM-PERENNE L)

Twenty populations of Lolium perenne originating from a range of habit ats in Europe were compared for isoenzyme polymorphisms and agronomica lly important quantitative traits in order to establish relationships of the levels of diversity with the origin of each population and to a ssess their suitability to be included in the European core collection of Lolium germplasm. Forty genotypes from each of the twenty populati ons and each genotype represented by three clonal propagules, were fie ld planted in a fully randomized spaced plant design and fifteen quant itative characters including yield, persistency, reproductive and dise ase resistence characters were evaluated over a period of two years. S even putative isozyme loci were assayed to compare the allozyme diverg ence of populations. The results of the isozyme survey indicate that 7 1-100% of the loci were polymorphic, 2.3-3.0 alleles/locus and the gen e diversity was varying from 0.234-0.410. Of the total allelic diversi ty 94% remained within populations (H-s) whilst only 6% was distribute d among populations (D-st). The differences between populations were d etermined on the basis of allele frequencies and multivariate analyses of quantitative characters. Populations significantly differed in the ir allele frequencies at all loci analysed. Random mating was predomin ant in all populations at most of the loci. The study revealed that th e German accession BA 10998 was clearly distinct from the rest both in quantitative characters and allele frequencies. German accession BA 1 1015 with the lowest gene diversity showed the highest genetic variati on for quantitative characters. However, no strict relationship was fo und between the genetic distance and the geograpical distribution of t he populations. Among the quantitative characters, flowering time show ed a strong relationship with the type of management practised at the collection site than their place of origin.