塊莖形成 Solanum屬 植物에서 四倍體 × 二倍體 交配에 依한 三倍體 및 四倍體의 生産

Production of Triploids and Tetraploids by Tetraploid × Diploid Crosses in Tuber-bearing Solanum Species

Tetraploids were crossed as female parent with various diploid clones iu tuber bearing Solanum species. The ploidy leveles of the progenies were determined by chromosome count and they were all triploids or tetraploids. The male diploid parent were grouped into two, one which produce 2n male gametes along with n gametes and the other which produce n male gametes mostly and very few 2n gametes if any. As female parents S. tuberosum and tetraploid S. chacoense produced abundant seeds when crossed to the diploids of the first type but very few seeds when crossed to the second type. A pentaploid endosperm with a triploid embryo seems to have competitive disadvantage to a hexaploid endosperm with a tetraploid embryo in these two species. S. stoloniferum and S. fendleri produced more seeds than S. tuberosum and S. chacoense with diploids of the second type. A pentaploid endosperm with a triploid embryo might develop better in S. stoloniferum and S. fendleri than in S. tuberosum and S. chacoense. Leaf index of triploid is similar with diploid and lower than tetraploid. The triploids had lower pollen stainability than diploids but had equal or higher stainability than the tetraploids. Pollen size of S. chacoense increased with an increase in ploidy level.