Breeding Of Rice Blast Resistant Rice Cultivar No. 131 (Pi2) And Kongyu 131 (Pi9)

Rice blast is the world's common threats of rice cultivation,which serious influence rice production and food security.As a big province of grain in our country Heilongjiang has become a frequent blast area in recent years,and the prevention and cure still depends on the variety of blast resistance to rice blast.The molecular Marker B-assisted selection(MAS)could help to select the targeting rice plants fast and accurately,reduce the linkage-redundancy and facilitate the recovery of genetic background to the maternal genetic background.So MAS could be used to culture the blast-resistant rice variety.The rice Kongyu131 is the major rice variety planted in Heilongjiang Province,as it is with the characteristics of short growing period,good quality,high yield,resistance to cold and better adaptation to different kinds of environments.The Kongyu131 don't have effective blast resistance genes.In the meanwhile,with the wide variety of rice blast physiological races,at the same time,the races easy to mutant,which cause Kongyu131 to suffer from this disease.Pi2 and Pi9 come from the rice varieties BL6,K22 and RH2 which have the broad-spectrum,high resistance to rice blast.This research aims to improve the blast-resistant ability of Kongyu131 and culture two new rice varieties Kongyu131(Pi2)and Kongyu131(Pi9)by introgressing Pi2 and Pi9 into Kongyu131 with MAS and Cross-backcross breeding methods respectively.The main results of this research are as follows:1.79 Single-spore strains were isolated from diseased samples of Kongyu131 which get from Heilongjiang and Hainan Provinces.2.One SSR Marker PI2-4 which is close linked to the target gene Pi2 was detected its polymorphism between the donor parent BL6 and the receptor parent Kongyu131 and could be used to identify the foreground of Kongyu131(Pi2).Another SSR Marker AP5930 which is close linked to the target gene Pi9 was detected its polymorphism between the donor parent K22 and the receptor parent Kongyu131 and could be used to identify the foreground of Kongyu131(Pi9).And another SSR Marker PI31 which is close linked to the target gene Pi9 was detected its polymorphism between the donor parent RH2 and the receptor parent Kongyu131 and could be used to identify the foreground of Kongyu131(Pi9).3.Two SSR Markers RM527 and RM19960 were selected.The two Markers located in Pi2/Pi9 gene on both sides.The two Markers could be used to identify the cross changes of the two sides of Pi2 or Pi9,which would be effectively reduce the linkage-redundancy in the culturing of Kongyu131(Pi2)and Kongyu131(Pi9).4.Screened 48 background selection Markers to identify the background of Kongyu131(Pi2)from the 300 pairs of SSR Markers.26 SSR Markers were selected to identify the background of Kongyu131(Pi9)which is nurtured by K22 and Kongyu131.24 SSR Markers were selected to identify the background of Kongyu131(Pi9)which is nurtured by RH2 and Kongyu131 respectively.5.By the foreground selection,cross changes selection and background selection of each generation of Kongyu131(Pi2)and field trail of blast-resistant.The rice plants which were Pi2 positive,two sides of the target gene exchange with double chromosome segment,genetic background was 100%and highly resistant to rice blast were got.6.Taking K22 and Kongyu131 as parental nurtured Kongyu131(Pi9).By the foreground selection,cross changes selection and background selection of BC4F3,BC5F1,BC6F1 and BC7F1 generations of Kongyu 131(Pi9)and field trail of blast-resistant.The BC7F1 generations of rice plants which were Pi9 positive,On both sides of the target gene exchange with double chromosome segment,genetic background was]00%and highly resistant to rice blast were got.These rice plants could be used to culture Kongyu 131(Pi9).7.Taking RH2 and Kongyu131 as parental nurtured Kongyu131(Pi9).By the foreground selection,cross changes selection and background selection of F1,BC1F1,BC2F1 and BC3F1 generations of Kongyu131(Pi9)and field trail of blast-resistance.The BC3F1 generations of rice plants which were Pi9 positive,two sides of the target gene with exchange double chromosome segment,genetic background was 95.83%were got.These rice plants could be used to culture Kongyu 131(Pi9).