| The thermo-photo-sensitive male sterile line BNS was developed in He'nan. In order to investigate the suitability of BNS in hybrid wheat breeding in Guanzhong area of Shaanxi, the method of interval sowing of BNS was conducted to identify the suitable sowing date for hybrid seed production and its propagation in Guanzhong area of Shaanxi. Seventy-eight hybrids between BNS and normal wheat lines were made and their fertility was checked to identify the restorer lines. Reciprocal F1 population of BNS and three lines (22Ai, Xiangcheng986, Zhengmai366) and four population (P1, P2, F1, F2)of BNS and three restorer lines (Zhoumai19, Kimai18, 9833) were set up to study the genetic characteristics of the fertility in BNS. The main results of this research are as follows:(1)The self-seedset rate of BNS had the tendency to rise with the sowing date postponed from October 1 to January 5 next year, while the self-seedset rate of check varieties (Xiaoyan 22 and Aikang 58) changed very little with the sowing date. The result showed that the fertility of BNS was sensitive to the sowing date. The average self-seedset rate of BNS was 1.41%, ranged from 0.11% to 4.96 %, indicating completely or highly sterility when it sowed before October 17 during four years, so BNS can be used in hybrid seed production. The average self-seedset rate of BNS sowed after November 18 was 68.23%, ranged from 43.79% to 98.96 %, which indicated that the fertility of BNS was restored, so BNS can be used in propagation. When sowed from October 25 to November 10, the self-seedset rate of BNS ranged from 17.48% to 46.77%, showing semi-sterility. The above fertility performance of BNS was stable among different years.(2) Three hybrids of 78 F1s, BNS/9833, BNS/SN055525 and BNS/CL0442, were restored to fertile during the three years, and their self-seedset were 118.54%,104.564% and 102.021% respectively. The results indicated that there are restoring genes in these three male lines, which could be used as restorer lines in further research and utilization. The self-seedset rate of 14 F1s between BNS and other wheat varieties (lines) including xi'nong 9871, xiaoyan 986 were less than 5%, showing that these varieties (lines) had no restorability to BNS.So these varieties (lines) could be used in breeding the new male sterile line. The self-seedset rate of other 61 F1s ranged from 5.79% to 78.01%, manifesting these lines cannot restore the sterile of BNS effectively.(3)There was no significance difference in fertility of reciprocal crosses of BNS and three lines (22Ai, Xiangcheng986 and Zhengmai366), indicating that male fertility of BNS was mainly controlled by nuclear genes. Four population (P1, P2, F1, F2) of BNS and three restorer lines (Zhoumai19, Kimai18, 9833) and the genetic model of major genes plus polygenes developed by Gai Junyi and Zhang Yuanming were used to study the genetic characteristics of the fertility in BNS. The frequency distribution of fertility in F2 population of three crosses showed characteristics of a mixed normal distribution, indicating the heredity of fertility was controlled by major genes plus polygenes, and the results of joint segregation analysis showed that the most suitable genetic model for the fertility was E-1 model. This is to say, the fertility of these three crosses was controlled by two additive-dominance-epitasis major genes plus additive-dominance polygenes. The additive effects of two major genes were -14.805, 0.223, -10.594, 6.83 and -16.669, -9.392 in three crosses, and the additive effects of polygenes were -15.937, -24.153 and -1.635, respectively. The heritabilitis of major genes were 89.177%, 87.211% and 83.22 % in 3 crosses, so the heritability of the major gene was relative high.It was concluded that both BNS'propagation and hybrid seed production could be conducted in Guanzhong area of Shaanxi, the fertility of BNS was controlled by two major nuclear genes and restoring genes could be found in common wheat. Hence, BNS can be used in hybrid wheat breeding program in this area. |
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