Study On Genetic Improvement Of Taste And Blast Resistance Of Several Rice Lines

As the main grain crop in China,rice breeding has experienced three major leaps.Breeding technology has developed rapidly,from systematic breeding to molecular marker rapid selection and genome breeding.In recent years,based on the functional gene molecular markers of traits,breeders have carried out line selection of target traits and bred a number of green rice varieties with high quality and yield,which not only meet the demand of consumers for rice quality,but also meet the actual production demand.In this study,soft rice YB8 containing fragrance gene Badh2-E2,rice blast resistance gene Pi2,Pikm and low amylose content gene Wx^mpwas identified;Y66 containing rice blast resistance gene Pikh and fragrance gene Badh2-E2;H82（Zhejing 165）containing low amylose content gene Wx^mp,rice blast resistance gene Pi2,Pikh,Pikm and Pita;057（Chunjiangnuo 7）containing rice blast resistance genes Pi5 and Pikm;060（Hefengnuo 331）,which contains rice blast resistance gene Pikh,is the parent,forming different hybrid combinations YB8/Y66,YB8/H82,057/060,etc.In addition,the F2 population material HP23 with YB8 as the parent and the F2 or F3 population material HPRF of a series of combinations were also included to improve the quality and resistance to rice blast by using the genotypic differences between their parents,so as to select lines with good taste and disease resistance.For the sake of variety breeding efficiency,this study will use anther culture technology to quickly obtain homozygous DH lines,and use molecular markers MPi2,Pikm,Pikh,Pita,molecular markers Indel-E2 of the aroma gene,and four primer markers of Wx^mp,a low amylose content gene,to identify the target gene of the anther culture lines.Based on the investigation of agronomic characters,rice lines with good genes of parents were screened.The main results of this study are as follows:1.The Wx gene of material YB8 was sequenced,and its Wx allele type was determined to be Wx^mp.The functional molecular marker of Wx^mpgene was designed by using its mutation site（G/A）according to the four primer blocked mutation system.Wx^mpgene can amplify 575bp and 237bp bands,while non Wx^mpgene can amplify575bp and 380bp bands.After identification,this marker can be used for Wx^mpgenotype identification.2.The anthers of HP23 and HPRF materials were cultured in vitro,and 194anther culture lines were obtained.According to the plant morphology,30 materials were selected for agronomic traits inspection.Four lines（W15,W30,W83,W139）were screened by combining the genotype detection of aroma gene,low amylose content gene Wx^mp,rice blast resistance gene,etc.W15 contains Wx^mp,Pi2 and Pid2genes;W30 contains Badh2-E2,Pi2,Pid2,Pita;W83 contains Badh2-E2,Wx^mp,Pi2,Pita,;W139 contains Badh2-E2,Wx^mp,Pi2.The panicle length and grains per panicle of the four materials were significantly better than those of YB8,among which the agronomic characters of W15 were significantly better than those of YB8,except for the average seed setting rate and 1000 grain weight.3.The F1 generation of YB8 and Y66 hybrids were cultured in vitro,and 32 lines were obtained.Three materials were screened by genotype identification,which polymerized the low amylose content gene Wx^mpof parent YB8 and the rice blast resistance gene Pikh of parent Y66.The agronomic character examination showed that the agronomic character of anther culture line 24 was significantly better than that of parent Y66,except the seed setting rate was significantly lower than that of parent Y66.4.13 lines were obtained from F1 hybrid plants of YB8 and H82 through anther culture.Through genotype identification,it was found that 3 lines of anther culture polymerized the aroma gene Badh2-E2 of parent YB8 and the rice blast resistance gene Pikh of parent H82.The agronomic characters of the three materials were investigated,and it was found that the plant height,panicle number,panicle length and seed setting rate of the three materials were significantly improved compared with the parent YB8.5.The F1 hybrid plants of 057 and 060 were cultured in vitro,and 3 lines were obtained.Through genotype identification,it was found that the Pi5 disease resistance gene of parent 057 and the Pikh disease resistance gene of parent 060 were aggregated in the three materials.In combination with agronomic traits,it was found that compared with parent 060,the number of grains per panicle in the three materials was significantly increased,and the seed setting rate,1000 grain weight,etc.were equal to or significantly improved compared with parent 060.The Wx^mpgene molecular markers designed in this study can be used for Wx^mpgenotype detection,providing a rapid selection tool for breeding rice with low amylose content.The selection of materials for aggregating superior genes of parents not only improved the parental traits,but also created new germplasm resources for rice breeding.