Study On Cross Breeding And Cultivar Comparison Of Petunia Hybrida

Petunia hybrida, originally found in South America, is an annual or perennial hebeceous flower, which is widely cultivated as "King of the flower bed" in world because of its outstanding advantanges such as rich color and flower shape, good adaptability etc. But due to the current seed resources in market are mainly imported from abroad, and expensive, so it is very necessary to develop our own petunia breeding program independly. In this study eight inbred lines of petunia were selected as parents for crossing according to GriffingⅡ,28 cross combinations and 8 self-crossed combinations were obtained. On one hand, the weight of each capsule, days from pollination to mature and seed germination ratio of all the combinations were investigated and compared, then based on the analysis of heterosis, combining ability and the heredity of flower colors of all the combinations, fifteen cross combinations with excellent ornamental traits and regular phenotype was selected; on the other hand, four cross combinations was selected to compare with popular cultivars in the market, sepecially in seed germination ratio and main ornamental characters, it clarified the traits advantages and application value of combinations we breed.The main results were as following:(1) The average weight of each capsule among Petunia hybrida combinations had significant difference. The average weight of each capsule of all cross combinations was 0.01976 g. Eighty percent of combinations had greater average weight than that of parents. The average of days from pollination to mature was 32.31 d among all combinations and they also differed significantly. The average seed germination ratio of 28 cross combinations was 82.37% compared with that of parents (69.80%), and we can see that fifteen combinations in the seed germination ratio were higher than their parents, so it shows obviously heterosis this aspect. Pollen germination rate of 11 inbred lines were seriously different, inbred lines H and 9 perform better than others, more than 50%, followed by inbred line S (44.75%), while inbred lines I and F White had the lowest pollen germination rate.(2) Heterosis analysis of main ornamental characters shows that plant height, flowers, branches, flowers, length of stalk, and internode distance in petunia have over-parent heterosis. The large variation of heterosis in all ornamental characters provides us more chances to select cross combinations in broad space.(3) Fifteen cross combinations with outstanding ornamental characters and regular phenotype were selected according to the analysis of heterosis, combining ability, the heredity of flower colors and field observation. They are Z×M,9×Y, Fwhite×Fyellow,9×I, 9×Fyellow, Z×Fyellow, Z×K, I×Fyellow, M×Fwhite, Y×M, Y×l, Z×Y, I×K, Y×Fyellow, and I×M.(4) According to the comparision with current popular cultivars in seed germination ratio and main ornamental traits, the cross combinations that we selected show some obvious competitive advantanges, which can undertake commercial application.