| Diseases and insect pest are the most important factors that affect the rice yield, while the rice blast, bacterial blight, brown planthopper, leaffolder, stem borer, sheath blight are the major diseases and insect pests in rice, which can lead to great damage of rice yield. According to the statistics of the National Agricultural Technology Extension and Service Center (NATESC), in2010and2011, the major of rice diseases and insect pest occurrence areas are88.57and95.23million hm2, respectively. And these diseases and insect pests seriously threaten the rice yield quality and its commercial value. Development of resistant cultivars has been considered as the important method to prevent these diseases and insect pests by many researchs.Three bacterial blight resistance genes Xa7, Xa21, Xa23and one insect-resistance gene crylC*were introgressed into the restorer line Xianhui207by backcrossing, multicrossing and molecular marker-assisted selection and pyramiding. Blast resistance gene Pi9, bacterial blight resistance gene Xa23, two brown planthopper (BPH) resistance genes Bph14and Bph15, insect-resistance gene crylC*were introgressed into restorer line R1005by backcrossing, molecular marker-assisted selection and phenotypic selection. The evaluation results of resistance, yield, growth duration, main agronomic traits and rice quality traits showed as follows:1. Nine bred lines carrying Xa7, Xa21, Xa23, Xa7+Xa21, Xa7+Xa23, respectively, under the genetic background of Xianhui207were selected. Seven strains of Xanthomonas oryzae pv. Oryzae, PXO61, PXO99, ZHE173, GD1358, FuJ, YN24and HeNll were inoculated to nine bred lines and their hybrid combinations which Jin23A used as female parent for identifying the bacterial blight resistances. The results showed that bred lines and hybrid combinations carrying Xa7gene were resistant to five Xoo strains, PXO61, GD1358, ZHE173, YN24and FuJ. The bred line and their hybrid combination carrying Xa21gene were resistant to six Xoo strains, PXO61, PXO99, ZHE173, GD1358, YN24and FuJ. The bred lines and their hybrid combinations carrying Xa23, Xa7+Xa21, Xa7+Xa23genes were resistant to all of seven Xoo strains. The results of yield trials, main agronomic traits test and rice quality analyses showed that three combinations, Jin23A/CY10012-2and Jin23A/1436(carrying Xa7, resistance to five and six Xoo Strains) and Jin23A/CY10004-7(carrying Xa7and Xa21, resistance to seven Xoo Strains) were similar as Jinyou207.2. Eight bred lines carrying Xa21+cry1C*, Xa7+Xa21+cry1C*, Xa7+Xa23+cry1C*, respectively, under the genetic background of Xianhui207were selected. The resistance of bacterial blight showed that bred lines and their derived hybrids were better than Xianhui207and Jinyou207. The pyramiding lines with different resistance genes under the genetic background of Xianhui207showed higher level and wide-spectrum of resistance than the bred lines with only one resistance gene. The protein content of CRY1C*expressing in hybrid combinations was lower than the bred lines and donor parent. However, the results of evaluating the insect-resistance in field showed that two hybrid combinations were completely resistant to leaffolder and stem borer. The results of yield trials, main agronomic traits test and rice quality analyses showed that Jin23A/CY10034-8(carrying Xa21+crylC*,1000-grain weight was higher than Jinyou207), Jin23A/CY10038-1and Jin23A/CY10039-1(carrying Xa7+Xa21+cry1C*) were similar as Jinyou207, and yield trials were higher than Jinyou207.3. Sixth-one bred lines carrying Pi9, Xa23, Bph14+Bph15, cry1C*, respectively, under the genetic background of R1005were selected.The results of blast evaluation at Enshi and Yichuang where is the rice blast prevalent areas, showed that two bred lines (CY11705-38and CY11707-6) carrying Pi9gene were resistant against blast. The results of blast evaluation at Enshi showed that four hybrid combinations (Q2A/CY11705-38、 Q2A/CY11707-6、 Chuannong1A/CY11705-38、 ChuannonglA/CY11707-6) were also resistant against blast. The evaluation results of yield, growth duration, main agronomic traits and rice quality traits showed that CY11705-38, CY11707-6and their hybrid combinations (Q2A/CY11705-38、 Q2A/CY11707-6、 Chuannong1A/CY11705-38、 Chuannong1A/CY11707-6) were as similar as R1005, Q2A/R1005and Chuannong1A/R1005, respectively.One bred line designed as CY11701-4carrying Xa23gene with the genetic background of R1005and its hybrid combinations Q2A/CY11701-4、 Chuannong1A/CY11701-4were resistant to seven Xoo strains, i.e. PXO61, PXO99, GD1358, ZHE173, HeN11, YN24and FuJ.The evaluation results of yield, growth duration, main agronomic traits and rice quality traits showed that CY11701-4, Q2A/CY11701-4and Chuannong1A/CY11701-4were as similar as R1005, Q2A/R1005and Chuannong1A/R1005, respectively, and yield trials were higher than contrast.Three bred lines (CY11711-14, CY11712-5and CY11714-100) carrying Bphl4and Bphl5genes were developed by the BPH resistance of both seeding and adult rice plants which were assessed in the greenhouse and field situation. The results showed that all of the three bred lines were highly resistant to BPH. However, the BPH resistance of9hybrid combinations which Q2A, Chuannong1A and Tianfeng A used as female parent showed that all of the hybrid combinations weren’t resistant to BPH. It means that the BPH resistance of Bphl4and Bphl5genes heterozygous plants was not better than homozygous plants. It can be concluded that that hybrid combinations ware not resistant to BPH if restorer line carrying BPH resistance genes and CMS line don’t carrying BPH resistance genes. |
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