A restriction fragment length polymorphism based linkage map of a diploidAvenarecombinant inbred line population

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Abstract
A population of 100 F6-derived recombinant inbred lines was developed from the cross of two diploid (2n = 14) Avena accessions, CI3815 (A. strigosa) and CI1994 (A. wiestii). Restriction fragment length polymorphism (RFLP) probes previously mapped in other grass species were used to develop a framework linkage map suitable for comparative genetics. Nine linkage groups were identified among the 181 loci mapped, with an average interlocus distance of 5 cM, and a total genetic map length of 880 cM. A cluster of five tightly linked crown rust resistance genes (Pca) was localized on the map, as were five loci identified by disease resistance gene analogs from maize, sorghum, and wheat. None of the five loci identified by the gene analogs were linked to the Pca locus. The linkage map was compared with previously published diploid and hexaploid linkage maps in an attempt to identify homologous or homoeologous chromosomes between populations. Locus orders and linkage relationships were poorly conserved between the A. strigosa × A. wiestii map and other Avena maps. In spite of mapping complications due to duplications within a basic genome as well as the allopolyploid constitution of many Avena species, such map comparisons within Avena provide further evidence of substantial chromosomal rearrangement between species within Avena.Key words: grasses, oat, genetic mapping, homoeology.