Abstract: The seed set of outcross was studied with photo-thermo-sensitive male sterile wheat line BS366 which was under different pollen density in this paper. The results showed there were no significant differences between positions of tiller, and the grain number per spike was 0.02 in BS366. This could ensure that the grains were from outcrossing seed set. The outcrossing rate increased firstly and decreased subsequently under the condition of adequate foreign pollens. The outcrossing rate was over 80% from the fourth to eighth day after BS366 flowered, and reached 88% on the fifth day. The ability of outcross seed set was better and the variation of outcross seed set was more distinctness in the middle of spike than that in other position of spike. The outcrossing rate was 94.7% in BS366 which was treated by artificial pollination time after time. In the filed, there was significant variation in the range of 1.5 m from restoration line and there was no difference out of 2.0 m from restoration line among the different rows of the outcrossing rate. In the 1.5-m distance from male sterile wheat line BS366 to restoration line, the outcrossing rate was higher and had no difference in different rows of BS366. The outcrossing rate and the weight of hybrid seed had more increase in the 1.0 m distance between parents when supplementary pollination was done. Therefore, it is important to achieve the purpose of high outcrossing rate in BS366. The first is that the width of BS366 planted should less than 2.0 m. Secondly, supplementary pollination should be made for 8 d after BS366 flowered, especially from the fourth to eighth day.

Key words: Wheat, Photo-thermo-sensitive male sterility, Outcrossing seed set, Pollen density

CLC Number: 

• S512.1

• S334.2+