Isozyme variation in germplasm accessions of the wild oat Avena sterilis L.
1993
Phillips, T.D. (North Carolina State Univ., Raleigh (USA). Dept. of Crop Science) | Murphy, J.P. | Goodmann, M.M.
Avena sterilis L., the cultivated oat progenitor, contains a store of genetic diversity that is readily accessible to the oat breeder. 1005 accessions from 23 countries and 679 collection sites were screened for variation using 23 enzyme systems. The frequencies of bands in accessions from the various countries were used to calculate the probability of genotype identity, the probability of a unique genotype and an adjusted polymorphic index. Accessions from Turkey and Lebanon had the largest polymorphic index values, Turkish and Moroccan accessions displayed the greatest numbers of bands. Accessions from Iran, Turkey, Iraq, and Lebanon had the largest mean probabilities of containing unique genotypes. Based on isozyme data, Turkey appeared to represent the center of diversity in this germplasm collection. Band frequencies calculated among countries were used in principal component analysis. Accessions from Israel and Morocco clustered together; accessions from Iran, Iraq, Turkey, and Ethiopia formed another group; and Algerian accessions formed an outlying group. Several isozyme bands had a regional distribution. These results suggested that choosing accessions from countries based on their groupings in the principal component analysis should secure a greater range of diversity than sampling from the collection at random. Cluster analyses based on Jaccard's distances calculated for all pairwise combinations of the 1005 accessions revealed six broad genetic groups of accessions. By selecting representative accessions from these six groups, oat breeders could most effectively sample the range of genetic variation in this A. sterilis colletion.
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