Genetic diversity among dwarf inbred lines of oats revealed by microsatellites
Morikawa, Toshinobu; Kuriyama, Satoshi (2004)
Agrifood Research ReportsMaa- ja elintarviketalous
New dwarfing genes were introduced from five accessions of wild oats, Avena fatua, to the cultivated form, A.byzantina cv. 'Kanota'. This study determined allelism between recessive dwarfing genes and clarified genetic variation among the dwarf inbred lines by using microsatellite markers. Three dwarf inbred lines 153, 169(AV198 and Av202) and 812 of BC1F5 generation were used for allelism test. These three lines have recessive dwarfing genes, but the allelism between them is unknown. Two inbred lines AV198 and AV202, which were selected from the same accession 169 in the different backcross combinations, showed remarkably differences in the plant height components. So, AV198 and AV202 were expected to have different dwarfing genes. Three inbred lines AV202, 153 and 812 were extremely dwarf and the dwarfing genes reduced the plant heights by half of the tall parent. AV198 showed semidwarfness that the height was about 85 cm. In the two crosses AV198 × line153 and AV198 × line812, the F1 progeny was dwarf and frequency distribution of the height in the F2 population fitted to the single factor inheritance 3 extreme dwarf (153 and 812 type): 1 semidwarf (AV198 type) ratio. Therefore, the recessive dwarfing genes of AV198, lines 153 and 812 were allelic, and the dwarfing gene of line153 and 812 were dominant for the gene of AV198. In the two crosses AV202 × line153 and AV202 × line812, the F1 progeny was tall and F2 progenies were segregated in the ratio of 7 dwarf : 9 tall. The results indicated that the recessive dwarfing gene of AV202 was located independently at the different locus from Av198, lines 153 and 812. Two dominant dwarf inbred lines 288 and 342 of BC1F5, AV21 having Dw8 of BC4F5 in A.byzantina, NC2469-3 and 96-8 having Dw7 and Dw6 in A.sativa were used for microsatellite analysis of 20 primers (AM). The AM primers amplified maximum 3 multiple alleles in the Kanota inbred lines. Nei s genetic distance was calculated and cluster analysis was carried out. The dendrogram showed two strongly different groups were apparent, A.sativa and A.byzantina. Four lines having the recessive dwarfing genes were clustered together. Because three of the four lines share allelic dwarfing genes, it might be presumed that the chromosome region around dwarfing gene could be inherited as a cluster. The AV21, however, having Dw8 was far away from Kanota tall parent and the other inbred lines. These results indicated that the small chromosome segments originated from wild oat still remained in the dwarf inbred lines.
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