Increasing genetic variability in common wheat by utilizing alien cytoplasms - effects of four Aegilops cytoplasms on the genetic variability of the F3 generation of the cross, Norin 26 × Norin 61.

Cytoplasmic effects of the four Aegilops species, i.e., Ae.squarrosa, Ae.kotschyi, Ae.speltoides and Ae.longissima, on the genetic variability of agronomic characters of wheat were investi**ated using a total of 460 F3 lines which were randomly derived from the cross combinations of allo- and euplasmic Norin 26 with euplasmic Norin 61. It was observed, coincidently with the trend observed in the F2 populations (TSUNEWAKI et al. 1985), that cytoplasm of Ae.kotschyi caused the most prominent effect. The cytoplasm increased, statistically significantly and/or consistently with the F2 result, the genetic variability of the seven out of ten characters examined. Cytoplasm of Ae.speltoides showed the second most appreciable effect, enlarging the genetic variability of the length of internodes, culm and spike. Cytoplasmic effects of Ae.squarrosa and Ae.longissima were neither distinct nor desirable. The principal component analysis revealed that none of the alien cytoplasms tested substantially modified the phase or structure of character association, though they more or less changed the genetic variability of individual characters. Cytoplasms with a larger genetic distance from wheat cytoplasm (TSUNEWAKI 1980) caused a wider range of effects, suggesting that new and desirable nucleo-cytoplasmic interactions may occur in a combination of relatively distantly related cytoplasmic and nuclear genomes rather than closely related ones.