The Research On Japonica Rice Breeding Of Broad-spectrum Blast Resistance Gene Pi40in Yunnan

Rice blast disease caused by Magnaporthe grisea which was a continuous threat to the stable of riceproduction in the world. The development of varieties with broad-spectrum and durable resistance toblast disease is essential for increased rice production and sustainability. Currently, there has beenreported in at least68blast resistance loci. of83major genes, Pi40is the latest major gene of whichwas identified with the broad-spectrum blast resistance gene by IRRI.Rice blast was the main disease in Yunnan Plateau, many japonica rice varieties were bred and plantin Yunnan. With the growth of these varieties,the big problem were the genetic background of cultivarswere quite narrow, rice blast resistant source was very single. The introduction of some new germplasmand genes are the very useful method. From2010, we introduced the new rice blast materials of Pi40,and some research are carried. The resistance spectrum analysed by Pi40and the races of YunnanPlateau Japonica.To identify the blast resistance spectrum reaction of Pi40with Yunnan complex anddiversity races. The SSR molecular markers tightly linked to Pi40were applied for molecularmaker-assisted selection. Some results are following:The polymorphism were checked using the300SSR marker for the balst susceptible varieties of LTHand the near-isogene line of IR83260-1-1-1-3-2-1-3-1-2carried Pi40, there were79SSR marker withthe polymorphic between LTH and IR83260-1-1-1-3-2-1-3-1-2, the polymorphism rate were23.66%.Using the balst susceptible varieties of LTH from Yunnan province as the female parent, and thenear-isogene line of IR83260-1-1-1-3-2-1-3-1-2carried Pi40as the donor, the cross was made and theprogeny were tested using the79SSR marker.21isogene lines with the LTH background were gottenand will be used for future research.From2010,the near-isogene line of IR83260-1-1-1-3-2-1-3-1-2carried Pi40was identifid for leafblast resistance under natural conditions in Baoshan, Yiliang and Yuxi in Yunnan procince at the sametime, the near-isogene line of IR83260-1-1-1-3-2-1-3-1-2carried Pi40showed a broad-spectrumresistance to the leaf blast and the disease grade were0,0,4; also resistant to he neck blast and thedisease grade are lower than5. Meanwhile in the lab,49rice blast races collection from different placein Yunnan were used for blast resistance test, and the near-isogene line of IR83260-1-1-1-3-2-1-3-1-2carried Pi40show a broad-spectrum resistance, and resistant to43races and susceptible to6races, thevarieties of race disease frequency was87.8%.For widely use the new blast resistance gene, IR83260-1-1-1-3-2-1-3-1-2as the donor, and thejaponica rice varieties of Yunjing19, Yunjing20and Dianchao4were used for the femaleparent,respectively, the cross was made and the progeny were tested using the79SSR marker. Thescreening was carried in the field in the same time,9new lines were selected for the breedingprogram.