0023-6152

AA00697606

22703

Unrefereed

0023-6152

AA00697606

1. The aim of this investigation was to make clear the occurrence of an alloplasmatic effect in carinata-cytoplasmic F₁ hybrids derived from the crosses between pekinensis plants having carinata's cytoplasm and some other species in Brassica. Plants of 8 species including 13 horticultural varieties were used. 2. In the production of F_1 hybrids, the carinata-cytoplasmic pekinensis plants behaved quite similarly as the normal pekinensis plants, revealing that these two kinds of plants were somewhat identical in their crossability irrespective of their cytoplasmic nature. 3. The carinata-cytoplasmic effect, i.e., chlorophyll deficiency, was observed exclusively in the carinata-cytoplasmic F₁ forms containing genomes aa, but not in the carinata-cytoplasmic F₁ plants containing genomes aac. Genome c added to genome a became to harmonize with the carinata-cytoplasm and could eliminate the carillata-cytoplasmic effect induced upon the genome a. 4. The carinata-cytoplasmic effect manifested itself conspicuously in (10Ⅱ + 1Ⅰ) plants, i.e., in pekinensis plants containing one extrachromosome derived from B. carinata (whose genome constitution is bbcc), and only slightly in 10Ⅱ plants. Compared with the vigor and the fertility of the plants, excepting the chlorophyll character, the carinata-cytoplasmic (10Ⅱ + 1Ⅰ) plants were definitely inferior to the carinata-cytoplasmic 10Ⅱ plants, and the pef;:inensis-cytoplasmic (10Ⅱ + 1Ⅰ) plants were, in turn, quite equal to or a little exceed the normal control pekinensis plants. Those facts enumerated above may be taken to indicate that an alloplasmatic effect appeared always severely incorporated with a genotypically unbalanced nucleus.