1989 年 54 巻 3 号 p. 513-521
Interspecific hybrids between S. lucani and S. surattense (violet and white varieties both) were successful in forward and reciprocal directions. The crossability index between them was low, which suggests low degree of crossability relationships between hybridizing parents. Meiotic studies on parental genomes showed normal bivalents, most of which were ring shaped and chiasma frequency was high.
Interspecific hybrids showed abnormal synapsis and unpaired chromosomes/chromosome parts with less staining ability. Metaphase I was characterized by the appearance of univalents, chains of three or six chromosomes, Y-shaped trivalent and rarely tetravalent association. Most PMCs contained 9 bivalents of which 5-7 were ring bivalents suggesting full homology between 7 chromosomes of S. surattense and 7 chromosomes of S. lucani, and the remaining 2 pairing partners exhibited partial homology by showing rod bivalents. Failure of synapsis in the rod bivalents could produce occasionally univalents only. Asymetrical chain made of three or six chromosomes indicated interchange of unequal segments due to heterozygosity for reciprocal translocation, in which 3 chromosomes from each parent were involved. Formation of Y-shaped trivalents was due to joint of interstitial break points. Further, occurrence of chromatid bridge with or without acentric fragments, presence of univalents, lagging and eliminated chromosomes indicated heterozygosity between parental genomes which contributed to formation of sterile pollen. However, all hybrids showed partial fertility except S. lucani×surattense var. white which was completely sterile.