The use of random amplified microsatellite polymorphic DNA and coefficients of parentage to determine genetic relationships in barley

Seventy European barley lines (Hordeum vulgare ssp. vulgare) and 29 Hordeum vulgare ssp. spontaneum accessions were evaluated for random amplified microsatellite polymorphism (RAMP). PCR was performed with 5'-anchored primers complementary to microsatellites in combination with random primers. Of 20 primers assayed in barley, only 9 produced well-resolved fragment patterns in H. vulgare ssp. spontaneum. On the basis of 56 polymorphic fragments, genetic distances between the two subspecies were calculated. Barley samples were subdivided according to growth habit and spike morphology. The smallest genetic distance was found between winter cultivars and accessions of H. vulgare ssp. spontaneum. The 20 primers assayed in the barley lines produced 140 polymorphic fragments that were used to calculate genetic similarity between lines. Mean genetic similarity within groups of lines ranged from 0.693 for 6-rowed winter barley to 0.657 for 6-rowed spring barley. Within these groups, mean values were significantly higher than mean genetic similarity between groups. Principal-coordinate analysis clearly separated the 2-rowed spring and 6-rowed winter types. Cluster analysis of spring and winter types showed subclustering consistent with the available pedigrees. Coefficients of parentage (COPs) were calculated for 29 spring and 20 winter lines. Mean values of 0.0741 for spring barley and 0.0458 for winter barley were obtained. RAMP-based genetic similarity matrices were compared with the corresponding COP-based matrices by the Mantel test. The correlation between them was poor (r = 0.21, P < 0.05), indicating little relationship between these two estimators of genetic similarity. The relative influence of factors involved in the calculation of these two estimators is discussed.