GENETIC-VARIATION OF RAPD MARKERS IN A PICEA-ABIES KARST - POPULATION

We report the results of the screening of 20 mapped RAPD loci over hap loid megagametophytes from 48 individual trees of an Italian populatio n of Norway spruce. LOD scores for 190 pairs of loci were calculated o ver families of megagametophytes from 'informative' trees, and linkage relationships between pairs of markers were analysed. Single-locus ge notypes were inferred from haploid progeny-array data and were used to estimate linkage disequilibrium between loci. Significant deviations from equilibrium did not appear to be randomly distributed over loci. Most of the markers analysed showed an excess of heterozygotes and fiv e out of 20 RAPD markers showed significant deviations from Hardy-Wein berg equilibrium. A weak spatial structure was detected by spatial aut ocorrelation at the scale considered (0-180 m), suggesting a lack of ' family structure' arising from isolation by distance. Nonrandom distri bution of the genetic variability was limited to some loci. Di- and tr i-locus spatial autocorrelation of loci showing linkage disequilibrium was also carried out.