抄録
Intra- and interspecific hybrids were easily obtained from crosses among two races (C. No. 1 and C. No. 3) of C. colocynthis Schrad. and a variety (V. No. 1) of C. vulgaris Schrad..
Chromosome behavior of the three parental races was normal throughout the course of their meiotic divisions. Chromosome conjugations at metaphase I in PMC's of the three hybrids showed 11 bivlaents in about 50% of the cells. The remaining cells showed irregular chromosome associations such as multivalents, mostly trivalents, and univalents. The frequency of the cells with multivalent associations differs among the three hybrids (Fig. 1 and Table 2). Pollen fertility was found to be approximately 50% in all of them (Table 3 and Fig. 3).
Morphological characters of the three hybrids were compared with those of their parents (Table 4, Figs. 4, 5 & 6). C. colocynthis was dominant over C. vulgaris in stripe pattern of exocarp and taste and color of flesh. On the contrary, C. vulgaris was dominant over C. colocynthis in seed and exocarp color.
Although C. No. 1 and C. No. 3 belong to the same species they differ in many morphological characters. C. No. 3 was dominant over C. No. 1 in color and stripe pattern of the exocarp. On the contrary, C. No. 1 was dominant over C. No. 3 in seed color.
Leaves of the three hybrids are intermediate in shape between their parents. Seeds and fruits of the three hybrids are intermediate in size and weight between their parents.
Female flowers of C. No. 3 were not produced until the end of August, however, two hybrids, C. No. 1×C. No. 3 and C. No. 3×V. No. 1 produced female flowers normally as early as the beginning of July.
All hybrids showed hybrid vigor and were resistant to Fusarium wilt.
