Chromosome Behaviors in Meiosis of the Inter-specific Hybrids between Colocasia esculenta (L.) Schott and C. gigantea Hook. f.

Abstract

Cytogenetical studies were carried out on the artificial F₁ hybrids between Colocasia esculenta (2n=28) and C. gigantea (2n=28). Of 15 individuals 14 possessed 2n=28, the diploid level of x=14, while 1 of 15 showed 2n=42, the triploid level.
The diploid hybrids contained two chromosome sets, one from each parental species. In spite of the similar morphology of chromosome complements to each other parental species, the PMCs of the diploid hybrids showed an abnormal feature in meiosis; almost all chromosomes formed univalents. This abnormal pairing form resulted in the complete sterility of its pollen grains.
The triploid hybrid contained two chromosome sets from C. esculenta and one set from C. gigantea. The PMCs of triploid hybrid showed strikingly different aspects in meiosis from those of diploid hybrids; homologous chromosomes of C. esculenta formed bivalents, while chromosomes of C. gigantea formed univalents. The rate of good pollen grains increased to 21%.