Comparison of the thermo-sensitivity difference of three sister lines of YS type thermo-sensitive male-sterile wheat lines

【Objective】 The study investigated the critical temperature difference of fertility exchange of thermo-sensitive male-sterile wheat lines and their genetics mechanism,and bred the thermo-sensitive male sterile lines that could be used in wide-range areas.【Method】 Experiments were done to compare the thermo-sensitivity of three sisters lines of YS type thermo-sensitive male-sterile wheat lines A731,A732 and A733,which were bred by backcrossing with the same recurrent parent 3314 and transferred the same major thermo-sensitive gene form 1B chromosome of T.spelta var.duh.,through sowing at different time and redeveloping tillers of the cuttillers at different time and combining their fertility exchang critical temperatures and rate of selfed seed under fertility condition with mteorologic conditions during the experiments.【Result】 It showed that the fertility exchang critical temperature of A731,A732 and A733 was 18.92,17.90 and 18.54 ℃ respectively.Selfed seed rates of ratooning of 3 sister lines were 9.80%,34.30%and 14.75%under fertility condition 27.85 ℃ respectively.However,when the temperature descended to 24.45 ℃,their selfed seed rates fell to 5.00%,10.01% and 8.35% respectively.When under different fertile conditions there were different fertility-restoration levels,which was irrelevant with their fertility exchange critical temperature value.【Conclusion】 Thermo-sensitive of three sister lines,which contained the same major thermo-sensitive gene,was different,indicating that the genetic mechanism of selfed seed rate of YS-type thermo-sensitive male-sterile wheat line was quite complicated.