Increasing genetic variability in common wheat by utilizing alien cytoplasms - Characterstics of nearly fixed alloplasmic lines selected in the cross, alloplasmic Norin 26*Norin 61.

Abstract

Effects of the cytoplasms of Aegilops squarrosa. Ae.kotschyi, Ae.speltoides and Ae.longissima on the effectiveness of selection and association of agronomic characters were investigated using a total of 200 F4 and F5 lines which were derived through selection in early generations of the cross combinations between allo- and euplasmic Norin 26 and euplasmic Norin 61. The selection was carried out on heading date, ear length, ear weight, ear number and yield per plant. The selection was effective for heading date and ear length and weight in all of the cytoplasms tested, No remarkable difference was recognized among the cytoplasms regarding the frequency of deviant lines for each selection character. It was observed, however, coincidently with the previously reported results of F2 and F3 populations, that the cytoplasm of Ae. kotschyi produced the widest range of combination of characters. Some promising early lines which were rather positively modified for the size of ear, were obtained in the cross combination carrying this cytoplasm. These lines may be used effectively as a genetic stock for wheat breeding in Japan. Effects of the other Aegilops cytoplasms were neither prominent nor con-sistent with the results observed in the F2 and F3.