Genetic Analysis About F₂Generation Of Petunia Hybrida Superiority Combination

Petunia hybrida Vilm, a kind of widely used annual flowers in the world, has a large popularity among people for its various colours and styles. With the development of creating new varieties in foreign countries, China is pushing the progresses of petunia breeding with independent patents. In order to protect the patents of new varieties of petunia, we abserved many characters of F1and F2of six combinations based on the good parents which has purified through years of self hybridization. At the meantime, the correlation analysis, path analysis, some initial discussions of the inheritance modes as well as the inheritance laws were performed to provide instructions of petunia breeding. Also the principal component analysis of F2was crried out to offer the objective standards for choosing excellent individuals. The main results are as follows:1.There exists very obvious differentiates of characters between F1and its correspoding F2of various combinations. The whole F2generation showed the degenerating trend to a large extent. The fading rate of flowers reached the highest to-40.5%. The funnelform length of F2was longer than of F1generation. From the aspect of genetic variation coefficient, the variation range of flower numbers is the largest which is50.8%and diameter is the smallest which is13.2%.2.The analysis of path coefficient and genetic correlation coefficient was performed according to the measurement of the11ornamental traits respectively. The result shows that the number of flowers was positive correlated to the plant range, plant height, branch number, leaf length as well as leaf width; flower diameter was positive correlatied to the sepals length, branch number and funnelform length; and funnelform length was positive correlated to the branch number, sepals length, internodal length, flower diameter, plant range as well as plant height; Pedicel length was positive correlated to internodal length, sepals length, leaf length, leaf width, plant height, plant range and branches number. And all the correlation coefficient achieved significant level respectively. Comprehensive analysis indicated that much more flowers plant varieties breeding requires for robust plants and more branches as well as shorter flower diameter; bigger flower diameter varieties breeding requires for longer sepals, more branch as well as less individual flowers; and try to choose fewer branches, shorter internodal length and sepals as much as possible for shorter pedicel length varieties. At last, this project obtained ten excellent individuals which ranked the top ten in the F2population by principal component analysis, and the individuals number were181,87,75,89,83,84,95,25,124,180. 3. The genetic model of pedicel length、flower diameter and funnelform length were analysised by using master genes and mulitiple genes mixture genetic model methods.It shows pedicel length and flower diameter were accord with the genetic model of C which controled by multiple genes and E model which controled by two major gene and multiple genes; Funnelform length was accord with the genetic model of C, D which controlled by a pair of major gene and multiple genes or genetic model of E which controlled by two pairs of major gene and multiple genes. This result can provide a theoretical basis for the ornamental traits breeding of petunia.