Mitochondrial DNA Diversity in Oat Cultivars and Species

Electrophoretic gel patterns of endonuclease restriction digests of mitochondria! DNA (mtDNA) isolated from oat ( Arena sativa L.) cultivars and other Avena spp. were examined for banding pattern differences indicative of cytoplasmic diversity. A knowledge of oat cytoplasmic diversity would he useful for assessing vulnerability of cultivars to pathogens, for elucidating phylogenetic relationships among Avena spp., and in testing for nuclear‐cytoplasmic interactions favorable to increased plant growth. The restriction enzymes Xho l, Pst l, Bam Hl, and Hind III were used to digest mtDNA isolated from 7‐d‐old etiolated oat seedlings. Among eight cultivars, variations in mtDNA patterns were observed for one band in Xho l, Bam l, and Hin Dall digests and two in PST digests. Exploit wild oat lines, including three A. sterilis L. and two A. fatua L. accessions, had mtDNA patterns very similar or identical to the cultivars. Patterns of two AABB genome tetraploids, A. abyssinica Hochst. and A. barbata Pott, and two AA genome diploids, A. strigosa Schreb. and A. canariensis Baum, Rajhathy et Sampson, differed from A. sativa ‘Victory’ by two to six bands, depending on the species and endonuclease. The CC diploid A. ventricosa Bal. cytoplasm mtDNA digest differed in at least 10 to 12 bands from the Victory mtDNA pattern. The AA and CC results are consistent with the idea that the cytoplasms of the hexaploid and tetraploid oats are derived from an AA‐genome and not a CC‐genome Avena diploid progenitor. The different mtDNA banding patterns of the diploids and tetraploids compared to the hexaploids indicate that the lower ploidy species may serve as a source for introgressing increased cytoplasmic diversity into hexaploid cultivated oats.