MOLECULAR ANALYSIS OF PLANTS REGENERATED FROM EMBRYOGENIC CULTURES OFWHEAT (TRITICUM-AESTIVUM L)

Total DNAs of plants regenerated from immature embryo-derived 2-month- old embryogenic calli of wheat (cultivars Florida 302, Chris, Pavon, R H770019) were probed with six maize mitochondrial genes (atpA, atp6, a pt9, coxI, coxII, rrn18-rrn5), three hypervariable wheat mitochondrial clones (K', K3, X2), five random pearl millet mitochondrial clones (4 A9, 4D1, 4D12, 4E1, 4E11) and the often-used wheat Nor locus probe (pT A71), in order to assess the molecular changes induced in vitro. In ad dition, protoplast-derived plants, and 24-month-old embryogenic and no n-embryogenic calli and cell suspension cultures of Florida 302 were a lso analyzed. No variation was revealed by the wheat or millet mitocho ndrial clones. Qualitative variation was detected in the nonembryogeni c suspension culture by three maize mitochondrial genes (coxI, rrn18-r rn5, atp6). A callus-specific 3.8-kb HindIII fragment was detected in all four cultivars after hybridization with the coxI gene. The organiz ation of the Nor locus of the plants regenerated from Florida 302 and Chris was stable when compared to their respective control plants and calli. The Nor locus in regenerants of Pavon and RH, on the other hand , was found to be variable. However, Nor locus variability was not obs erved in 14 individual seed-derived control plants from either Pavon o r RH sources. In Pavon, a 3.6-kb TaqI or a 5.6-kb BamHI(+) EcoRI fragm ent was lost after regeneration. In one of the RH regenerants, which l ost a fragment, an additional fragment was observed.