Improvement Of The Bacterial Blight Resistance Of Hua201S, A Photo-Thermo-Sensitive Genic Male Sterile Lines Of Rice

Seven indica photo-thermo-sensitive genic male sterile lines (PTGMS) containing bacterial blight resistant genes (Xa7 or Xa21 or both) developed by MAS and the recipient parent (Hua201S) were used as experiment materials in the study. The agronomic traits, growth characteristics and fertility dynamic performance were investigated under natural and artificial control conditions at Wuhan in 2008 and 2009.13 Xoo strains were used for identifying the resistance against rice bacterial blight. Seven breeding PTGMS lines and the recipient parent were used as female parents for crossing two set male parents by NCⅡdesign. The general combining ability and the specific combining ability of female and male parents were investigated and analyzed for yield and main agronomic traits in the year 2008 and 2009 at Wuhan. Several heterotic combinations were selected. The main results are as follows:1. Of seven newly developed indica PTGMS lines, the fertility alteration and stability of YR7009,YR7014,YR7016 and YR7023 were similar as the recipient parent (Hua201S). But, the performances of fertility alteration in YR7020,YR7026 and YR7027 were not satisfacted for applying in breeding practice.2. Under the artificial control conditions, four out of seven PTGMS lines, YR7009,YR701,YR7016 and YR7023 showed that the critical point temperature (CTP) of fertility alteration was lower than 23.5℃in daily mean temperature (19℃/night and 27℃/day). The CTP OF the other three lines was above 23.5℃.3. The PCR analyses of target gene with molecular markers illuminated that the BB resistance gene(Xa21 and Xa7) were homogeneous in each lines and they can be inherited to the next generation stably.4. The result of resistance identification in field showed that the virulence of PXO99 was stronger than ZHE173 and PXO61. Seven PTGMS lines containing BB resistance genes (Xa7 or Xa21 or both) were resistant against above three Xoo strains. susceptible to two Xoo strains, FuJ and YN24。The lines containing Xa7 were resistant against FuJ and YN24. The lines,YR7023,YR7026 and YR7027containing both Xa7 and Xa21were resistant against all of 13 Xoo strains.5. The analyses of general combining ability (GCA) and specific combining ability (SCA) showed significant at 5% or 1% levels for main traits. The additive effects were more important than non-additive effect. The effects of the GCA and SCA on various characters were not significantly related each other. YR7009 and YR7014 in seven PTGMS lines showed high general combining ability (GCA) in grain weight per plant. Guangchao624 and C60261 in restorer lines showed high general combining ability (GCA) in grain weight per plant. Specific combining ability (SCA) among all the combinations were not significant at 5% or 1% levels.6. Several heterotical combinations were selected among tested crosses. In 2008, YR7014/Keyou1 hao, YR7009/TME62089,YR7009/Ghuangchao624. YR7014/Guangchao624 showed high competitive heterosis. In 2009, YR7009/C60261 and YR7014/C60261 showed high yield.