Studies On Heredity,Heterosis And RAPD Markers Of Fertility Gene For Thermo-sensitivity Male-sterile Line In Flax

A new thermo-sensitivity male-sterile line of Flax (Linum usitatissimum L.) were studied in this paper. With the research methods of traditional breeding and molecular biology, this work mainly focus on the analysis of heredity,heterosis and RAPD Markers of fertility gene for the new thermo-sensitivity male-sterile line 1S of Flax. The main results in this paper are as follow:1. Heredity of the thermo-sensitivity male-sterile line of FlaxThe identification of male fertility for F₁ and F₂ generations from six cross combinations under the natural conditions showed that all of F₁ populations were male fertile and in F₂ populations , there were fertile plant individuals and sterile ones, which indicated that the sterility of thermo-sensitivity male-sterile line of Flax was controlled by recessive nucleus genes. Through chi-square tests, the segregation ratios of fertile plants to sterile ones in observed F₂ segregation populations were coincided with the ratio 3:1 that is the segregation ratio of recessive single gene in F₂ generations.2. Heterosis of the thermo-sensitivity male-sterile line of FlaxThe heterosis of main agronomic and yield characters of F₁ and F₂ generations respectively from six cross combinations was analyzed. As far as the average heterosis of different cross combinations was concerned, both F₁ and F₂ genarations expressed negative over male-parent heterosis in plant height and technical length traits, however, positive over male-parent heterosis existed obviously in yield traits, including fruits per plant,seeds per fruit,1000-seed weight and seeds yield per plant. Compared with F₁ generations , the average heterosis of F₂ generations was lower.The order of heterosis is seed yield per plant>fruits per plant>1000-seed weight>seeds per fruit. The heterosis expression of F₁ and F₂ generations from different cross combinations was different. The heterosis of 1S×Heiya No.15 in yield traits was the largest among the six cross combinations not only in F₁ genarations but also in F₂ genarations.