Abstract: The BNS sterile line is sensitive to temperature. It becomes infertile in the low temperature of sensitive period but restores fertility in high temperature. The fact has been found that the temperature of wheat growth stage is higher in 2014-2015 cultivation periods however the setting rate of BNS autocopuation is 50% lower than colder 2011-2012 cultivation period. In order to probe the reason resulting in the above phenomenon, it was analyzed that how the temperature of wheat growth stage altered and what were the relationship between temperature alteration and setting rate of self cross during 2012-2015. Based on the temperature changes, it was discovered that different winter/spring temperature alteration significantly influenced the setting rate of BNS sterile line, namely, warm winter and cold spring could result in less setting rate but cold winter and warm spring could increase setting rate of the line. The phenomenon may be because that warm winter promoted wheat ear development rate and beginning of sensitive period, along with normal or warm spring, which results in more rapid appearance of reproductive growth and higher setting rate, and vice versa. Therefore the typical warm winter and cold spring in 2014/2015 cultivation period brought the serious decline of setting rate. Further correlation analysis shows that, in the BNS line, the setting rate of self cross is negatively correlated with the accumulated temperatures during sow-ear stages, but positively correlated with ≥15℃ average effective accumulated temperature and accumulated days of average ≥15℃ after March 1 of second year. The threshold temperature of fertility transformation is 12℃, and ≥15℃would significantly influence setting rate. It was also found that the regression equation which based on two significantly positive temperature parameters might predict the setting rate of BNS sale sterile line. In short, the ≥15℃ average temperature obviously affected reproductive transformation of the BNS temperature-sensitive sterile wheat, and average ≥15℃ effective accumulative temperature and accumulated days of average ≥15℃ date were the two important parameters of the BNS reproductive transformation.

Key words: Wheat, BNS male sterility, Self-seedsetting rate, Accumulated temperature, Accumulated days