Interspecific Cross-Breeding between Iris domestica and I. dichotoma

Interspecific hybridization is an important way to acquire new traits in the breeding of Iris. Both Iris domestica and I. dichotoma are native wild species in China and both bloom in summer. The result of AFLP (Amplified Fragment Length Polymorphism) analyses indicated that the genetic relationship between them was relatively closer with respect to some other species in Iris genus. When I. domestica was used as female parent, the flower color of offspring was significantly similar to that of female parent, while when I. dichotoma was the female parent, the general appearance of the only interspecific hybrid plant was intermediate between its parents. Its flower color was purple which differed from that of either parent, who were respectively orange and white. Its blooming time was about 10: 00 am, while I. domestica bloomed at 8: 00 am and I. dichotoma at 3: 30 pm. In AFLP analysis, it had bands specific to both parental species indicating that it was interspecific hybrid. Self crossing of this F-1 plant was made, and the seed setting rate was 58.3% while no capsule was set when backcrossing with pollen parent. Germination ratio of the seeds obtained from the F-1 plant was very low, only 3.08%, but F-2 seedlings were obtained finally. The F-2 hybrid plants developed flowers possessing richer variations which were very beneficial to future breeding as well as preparation for QTL analyses of the major ornamental traits.