Random amplified polymorphic DNA and pedigree relationships in spring barley

Random amplified polymorphic DNA (RAPD) in 27 inbred barley lines with varying amounts of common ancestry and in 20 doubled-haploid (DH) lines from a biparental cross was investigated. Of 33 arbitrary 10 base primers that were tested, 19 distinguished a total of 31 polymorphisms. All polymorphisms were scored as dominant genetic markers except for 1, where Southern analysis indicated the presence of 2 codominant amplification products. The inheritance of 19 RAPD polymorphisms and 1 morphological trait was studied in the DH lines. There was no evidence for segregation distortion, but a group of 4 tightly linked loci was detected. The frequencies of RAPD polymorphism in pairs of inbred lines were used to compute values of genetic distance (d), which were compared to kinship coefficients (r) between the same pairs of lines. A linear relationship between r and d was evident, but low values of r gave poor predictions of d. Cluster analysis showed that groups of inbred lines based on r were similar to those based on d with some notable exceptions. RAPD markers can be used to gain information about genetic similarities or differences that are not evident from pedigree information.