| Rice often encounters the invasion of rice blast bacterial blight and brown planthopper,which seriously affects rice yield and grain quality.The use of chemical pesticides to control pests and diseases is a common method,but seriously deviates from the purpose of green and safe production of crops.Developing new varieties with multi-resistance genes is an effective measure for the green production.In this study,we used the rice variety "Huanghuazhan",which is widely used in production,as the basis,the pyramided lines with multi-genes for disease and insect resistance and grain quality were developed by cross and backcross schemes combined with a genomic selection strategy,In addition,in order to further meet the needs of the people,new pyramided line with low amylose content were further cultivated based on the high-quality pyramided line that had been cultivated to resist disease.By analyzing the agronomic traits and the quality performances of these pyramided lines,the breeding value was evaluated.The main results are as follows:1.Genotypes of rice blast resistance genes(Pi1,Pi2,Pi9,Pigm),brown planthopper resistance genes(Bph6,Bph9,Bph14),bacterial blight resistance genes(xa13,Xa21)or aroma genes(fgr)were identified.24 pyramided lines with 3-4 disease resistance genes and aroma genes were selected to evaluate their agronomic and quality traits.2.The resistance of four pyramided lines introduced bacterial blight gene was identified by inoculating ZHE173 and PXO99 strains.The results showed that 21WHP7(Pigm+xa13+fgr),21WHP20(Pi1+xa13+Bph6+fgr),21WHP23(Xa21+Bph9+fgr)and21WHP24(Pigm+xa13+Bph6+fgr)significantly increased the resistance to bacterial blight than Huang Huazhan.At the same time,the blast resistance of four rice blast resistance lines,21WHP20,21WHP24 and 21WHP25/26(Pi1+Pigm+Bph6+fgr),were identified by leaf blast at seedling stage.It was found that the blast resistance grade of the pyramided lines was significantly higher than Huang Huazhan.3.The agronomic and quality characters of 24 new pyramided lines were investigated.the results showed that there were no significant differences in yield,panicle length and quality among the pyramided lines.however,there were some differences inheading date,plant height,panicle number,primary branch number,grain number per ear,grain length,seed setting rate and 1000-grain weight.According to the effects of different resistance genes and quality genes on agronomic and quality traits,pyramided lines composed of Pi9,Bph9 and Xa21 were recommended.4.Based on the polymerization line 21WHP24(Pigm+xa13+Bph6+fgr)with four genes,the low amylose content gene Wxmq was further polymerized by genome selection breeding technique,and a high quality multi-resistant 5 gene pyramided line(Pigm+xa13+Bph6+fgr+Wxmq)was obtained.compared with Huang Huazhan,the amylose content decreased significantly from 15% to about 10%.5.Based on the analysis of field agronomic characters of 5-gene pyramided line selected by plot planting,it was observed that there were great differences in heading date among individual lines.Through the analysis of genetic background on breeding chip,it was found that there were non-target gene fragments of dth2 and COLD1 on chromosomes 2 and 4,respectively.On this basis,new lines with 7 genes pyramided line such as cold tolerance,short growth period,disease and insect resistance and high quality were further selected.The newly developed lines with high-quality and multi-resistance rice material with the background of "Huanghuazhan" selected in this study has lay a good material foundation for the promotion and application of green high-quality rice. |
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