Breeding Blast Resistant Aromatic And Soft Rice Varieties By Molecular Marker And Anther Culture Techniques

In this study,the medium-maturing mid-season japonica variety Rundao 118 containing the rice blast resistant gene Pikm,and soft rice variety Nanjing 9108 with rice blast resistant gene Pb1,low amylose content gene Wx-mq,and fragrance gene badh2 were used for hybrid pyramiding breeding.In order to speed up the breeding efficiency,molecular marker-assisted technology was utilized to select target traits,and the molecular markers for Pikm,Pb1,badh2 and Wx-mq were Pb1-7,Pikm-2,fgr6 and Wx-mq respectively.By combining molecular marker detection with field phenotype identification,Pb1,Pikm,Wx-mq,and badh2 were successfully aggregated,and then assisted by anther in vitro culture technology,stable new rice lines with good resistance to rice blast,good taste quality and high yield,were cultivated rapidly.1.Combing molecular marker technology with field phenotype identification,6 out of30 F3 plant families were selected to anther culturation in vitro.Among the 1,332 green seedlings from anther culture,the plants haplontic or with poor leaf morphology were eliminated,and 80 strains were selected and harvested for the plot test.And then 16 strains with good performance were selected for testing and agronomic character investigation in field.2.Carrying out molecular marker detection of Pb1,Pikm,Wx-mq and badh2 gene to the 16 strains.The results showed that,5 strains contained Pb1,Pikm,Wx-mq and badh2 genes,7 strains contained Pikm,Wx-mq and badh2 genes,three strains contained Pb1,Pikm and badh2 genes.,and one strain contained Pb1 and Wx-mq genes.3.Field identification of blast resistance of 16 strains were performed.Eight strains carrying two rice blast resistance genes,Pb1 and Pikm,HP-12,HP-15,HP-16,HP-18,HP-22,HP-26,HP-27 and HP-53,all showed moderate blast resistance,with an average blast resistance composite index of 3.0.It was more resistant to blast than the control varieties Nanjing 9108 and Rundao 118.4.The grain quality,aroma and other appearance qualities of 16 strains were detected.The results showed that the endosperm of 14 strains containing Wx-mq was opaque and misty,and the amylose content was 11.9 on average,which was soft rice type,consistent with the results of molecular marker detection.All the 15 strains containing the aroma gene badh2 had aroma,but the degree of aroma was different.3 strains smells very sweet,8strains had middle aroma,and 4 strains smells the light fragrance,which was presumed to be caused by different genetic backgrounds.