New cytoplasmic male sterility sources in common wheat: Their genetical and breeding considerations.

Nuclei from Triticum aestivum L. cultivars 'Penjamo 62' and 'Siete Cerros 66' were introduced into the cytoplasms of different species of Aegilops and some subspecies (varieties) of T. dicoccoides by backcrossing. The sterile alloplasmic lines obtained were compared with the normal cultivars used as the recurrent pollen parents. According to the cytoplasmic effect, these cytoplasms were subdivided into three main groups. The first group possesses C(u) type cytoplasm, the second one possesses M type and the third group includes S, C and G type. Promising male sterile cytoplasms for hybrid wheat production were found in Ae. mutica, Ae. triuncialis and T. dicoccoides var. 'spontaneovillosum'. Based on these results and other information some conjectures were made concerning hybrid wheat breeding and phylogenetic differentiations of the cytoplasm.