| Rice is the staple food for more than half of the population over the world.But it always bear the dangers of many kinds of diseases and pests in growth process,and rice blast affect the yield and quality of rice.Rice blast is an epidemic diseases,and it caused by the sac fungi,and it happened in different periods of rice.Long-term production practice have proved that the use of pesticide control rice blast could cause the environmental pollution.Mining of new resistance loci,therefore,and importing the genes or loci into a new variety with the marker-assisted selection,are the most effective and insurance measure.Rice landraces evolved the unique resistance genes under the long-term natural selection.Mining and using these resistance genes are a direction of current research rice blast.Taihu Lake area is located in the middle and lower reaches of the Yangtze River,belongs to the ancient origin of rice,containing many excellent resources.Discovering and identifying new resistance loci from the resources are of great significance to rice blast resistance breeding work.Two varieties which belong to Japonica rice,Jiangnanwan and Suyunuo,were selected to construct RILs for QTL analysis.The parents and population were inoculated by Hoku 1 to identify the rice resistance at different place for three times.To dissect the genetic factors of rice blast,a linkage map which covered 1690.76cM on the chromosomes with an average distance between two connected markers of 18.18cM was established by QTL IciMapping 4.0.The phenotypic data of F2:5 RILs,F2:6 RILs and F2:7 RILs were used for QTL analysis.A total of 10 QTLs(LOD>2.5)for the traits were detected.Seven of the QTLs involved in the resistant to panicle blast,two QTLs(qPbj-7-1,qPbj-11-1)located on chromosome 7 and 11 were detected in Nanjing 2013,two QTLs(qPbj-7-2,qPbj-11-2)located on chromosome 7 and 11 were detected in Nanjing 2014,three QTLs(qPbj-6-1,qPbj-9-1,qPbj-11-3)located on chromosome 6,9 and 11 were detected in Nanjing 2015,respectively.qPbj-11-1 were all detected in the 1.48 cM region between markers RM27273 and RM27381 on the long arm of chromosome 11,explained 39.92%,53.68%and 42.49%phenotypic variation for panicle blast.QPbj-7-1 with LOD scores of 4.86 and qPbj-7-2 with LOD scores of 2.84 were detected in Nanjing 2013 and Nanjing 2014,respectively.They were all located in the 9.08 cM region between RM3186 and RM346 on chromosome 7,and explained 6.91%and 2.88%of the phenotypic variance.QPbj-6-1 with LOD scores of 3.28 and qPbj-9-1 with LOD scores of 2.55 were detected in Nanjing 2015.They were located in the 26.37 cM region between RM276 and AP5659-5 on chromosome 6 and 10.21 cM region between RM3164 and RM2144 on chromosome 9,respectively.QLbj-11-1 were all detected in the 1.48cM region between markers RM27273 and RM27381 on the long arm of chromosome 11,explained 18.84%,23.60%,and 10.91%phenotypic variation for leaf blast in three generations respectively.Considering the positive relationship between the panicle and leaf blast,there exist a major gene on chromosome 11 might not only influence panicle blast but also leaf blast resistance in Jiangnanwan.It affords a new genetic source for breeding blast resistance cultivars,and will improve understanding of the molecular basis of host resistance to panicle blast. |
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