| Alteration of growth habit and variation of heading
time induced by the alien cytoplasm in common wheats1) T. KINOSHITA*, I. OHTSUKA** and H. KIHARA** * Plant Breeding Lab., Faculty of Agri., Hokkaido Univ., Sapporo, Japan * * Kihara Institute for Biological Research, Mutsukawa, Minami, Yokohama, Japan Based on the extensive studies on nucleo-cytoplasmic substitution in wheats and their relatives, various cytoplasmic effects on genome manifestation have been reported (KIHARA 1951, FUKASAWA 1953, MAAN 1975, TSUNEWAKI et al. 1976). Recently KIHARA (1973, 1975) has suggested the possible utilization of the nucleo-cytoplasmic hybrid, as a mean of plant breeding for nucleo-cytoplasmic heterosis as it was revealed that the alloplasmic common wheats with Aegilops squarrosa cytoplasm provided complete pollen fertility and vigorous growth. SEMENOV (1978) reported the alloplasmic common wheat with Ae. ovata cytoplasm which had economically useful characters. In this paper, the authors clarified the cytoplasmic effect on the growth and flowering habits by using the alloplasmic common wheats with the cytoplasm of Ae. ovata. In addition, effects of the other cytoplasms such as Ae. squarrosa, Ae. umbellulata, Ae. vavilovii were also investigated both in the field and under the controlled environment. The alloplasmic common wheats used in the experiments are given in Table 1a. They have been established by the successive backcross method. After the proposal by TSUNEWAKI (1969), alloplasmic lines are expressed as the following example in the text; (ovata)-Chinese Spring indicates the nucleo-cytoplasmic substitution line of Triticum aestivum cv. Chinese Spring with cytoplasm of Ae. ovata. Field experiments were carried out in Sapporo (N43o, E 142o) and Kurasahiki (N35o, E134o) in Japan. Winter and spring wheats were sown in September and in April in Sapporo, respectively, while the both cultivars were sown in November in Kurashiki, with 20 cm x 40 cm spacing. The autors wish to express their sincere thanks to Prof. S. YASUDA and Mr. FUKUYAMA for their co-operation in the experiment at Kurashiki. 1. Heading time in the fields The nucleo-cytoplasmic substitution lines and their nucleus donors were grown in Sapporo and Kurashiki from 1977 to 1978 for the comparative observation of their heading time. Table 2 shows the heading dates of the cytoplasmic substitution lines and the deviation from their nucleus donors in two places. When the cultivar Chinese Spring was compared with the alloplasmic lines with Ae. ovata. Ae. squarrosa, Ae. umbellulata and Ae. vavilovii, significant differences were observed in the heading time. Among the alloplasmic lines of Chinese Spring, the heading time of (ovata)-Chinese Spring was most remarkably delayed as compared with the nucleus donor, by 35.2 days in Sapporo and 11.0 days in Kurashiki. The similar effects of Ae. ovata cytoplasm to Chinese Spring was noticed in the heading time in P168. In both lines, a considerable number of unemergent and sterile tillers were observed in Sapporo. |
| 1) The study is conducted as a part of The Co-operative Project on NC-heterosis initiated by Kihara Institute for Biological Research. |
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