A COMPARATIVE-STUDY OF THE MITOCHONDRIAL GENOME ORGANIZATION IN IN-VITRO CULTURES OF DIPLOID, TETRAPLOID, AND HEXAPLOID TRITICUM SPECIES

Southern-blot hybridizations of total DNA to mitochondrial DNA (mtDNA) probes were used to investigate the extent of mtDNA variability in cu ltures derived from immature embryos of diploid (Triticum monococcum, genomic formula: AA, T. tauschii, genomic formula: DD), allotetraploid (T. durum cv ''Creso'', genomic formula: AABB). and allohexaploid (T. aestivum, genomic formula: AABBDD) wheat species. Similar distinct ch anges in mtDNA organization were observed in in vitro cultures of the derived tetraploid and the hexaploid species with related genomes. The tetraploid and hexaploid species share the B genome and mtDNA variabi lity in in vitro culture is known to be under nuclear control. These r esults suggest that a study of B genome diploids and other polyploid c ombinations would now shed light on whether or not mtDNA variability i n tissue cultures is under B-genome control.