engleski

Genetic diversity among populations of Lolium perenne L. measured by RAPD markers

Lolium perenne L. (perennial ryegrass is distributed all over Europe, which is considered to be the centre of diversity. It is the most important forage grass in North-West and Central Europe. Most of the current cultivars are synthetics or openpollinated varieties and, like ecotypes, they represent heterogenous populations. Informations on the amount of genetic diversity in perennial ryegrass is necessary to enhance the effectiveness of breeding programs. Genetic diversity was investigated by means of RAPD (Random Amplified Polymorphic DNA) markers in 13 ecotypes and 13 cultivars based on 24 individuals per populations. Six primers amplified a total 169 polymorphic bands. On average cultivars revealed a higher degree of polymorphism than ecotypes (161 vs. 151). The mean number of pairwise differences (i.e. Euclidean distance) also reflected these findings (cultivars 15.5 to 29.9, ecotypes 12.8 to 26.3). Genetic similarity (GS) within populations, calculated according to Jaccard, ranged from 0.30 to 0.81. Among the 624 plants analyzed, no indentical banding patterns could be detected. Cluster analysis as well as principal coordinate analysis (PCoA) performed on GS estimates resulted in a clear separation of all populations. AMOVA (Analysis of Molecular Variance)was applied to partition the variation amnod and within populations, and within and among groups (cultivars vs. ecotypes). A significant genetic difference was found between ecotypes and cultivars. On average, variation within populations was larger (70%) than among populations (30%). The latter can be used as a measure of genetic diversity and was slightly higher for cultivars than ecotypes. The results are discussed with respect to the interrelationship among ecotypes and cultivars.

Lolium perenne; populations; genetic diversity; AMOVA

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