Identification And Advantage Analysis Of Newly Improved BT Type Japonica Rice Male Sterile Line

Indica-japonica hybridization is the effective means to improve the flowering habit of BT-type japonica rice,resulting in promoting the yield of hybrid seed of japonica rice.Recently,a series of BT-type male sterile lines deriving from indica-japonica crosses and showing partial-japonica phenotype have been bred by the Jiangsu Changshu Agricultural Science Institute.In order to identify the applying value of BT-type male sterile lines,5-55A,5-108A and 5-110A were selected.Taking Wuyunjing7A and ChangllgA,two japonica male sterile lines as control,the flowering habits,out-crossing characters and the sterility stability of these three sterile lines were identified and analyzed.Meanwhile,using the large-area planted Changyou4 and Changyou6 as control,the yield traits and heterosis of Changyou16-15,Changyou17-7,Changyou17-6,Changyou16-7 and Changyou16-8,deriving from the targeted BT-type male sterile lines were identified and analyzed.The main results were as following:1.Compared with Wuyunjing7A and Changll9A,the initial heading date of 5-55A,5-108A and 5-110A was 8-15d earlier,which increased the freedom of their combination utilization.2.Compared with Wuyunjing7A and Changll9A,the full-blooming stage of 5-55A,5-108A and 5-110A was 1-2d earlier and more concentrated.5-55A,5-108A and 5-110A showed he earlier daily blooming,more obvious flourishing peak period,larger flower opening angle,more stigmatic explosure and stronger vitality,and their outcross rate were higher by 10%,which were helpful for the high yield of hybrid seeds.3.Compared with Wuyunjing7A and Chang119A,5-55A,5-108A and 5-110A exhibited relatively higher plant height,longer ear and grain shape with the length-width ratio of 2.5-2.9.Moreover,5-55A,5-108A and 5-110A showed the detained abortion pollen grains and the bagging-self-fruited ration of zero,indicating these male lines were stably sterile,which were similar with Wuyunjing7A and Chang119A.4.Compared with the Changyou4 and Changyou6,the newly 5 hybrid combinations of Changyou16-15,Changyou17-7,Changyou17-6,Changyou16-7 and Changyou16-8 showed the positive characteristic advantages on plant height,number of efficient tillers,total number of grains,number of grain per plant,ripening rate and yield per plant,and the competitive advantage were over 40%on the yield per plant.As the above results,the newly bred 5-55A,5-108A and 5-110A are good at coordination,showing strong heterosis and seed-produced characteristics,and these male sterile lines might be useful in breeding of japonico hybrid rice.