| Rice(Oryza sativa L.)is one of the most important staple food crops in the world.The production of rice directly affects the security and stability of world’s grain.But rice blast caused by Magnaporthe grisea is one of the most devastating disease and largely reduces the yield of rice every year..Breeding and rational utilization of disease resistant varieties are the main approach for rice blast control.Further more,using disease resistance genes to select resistant varieties is the most economical,effective and environmentally friendly method.So,in this study,the rice germplasm resources in Ningxia as material.the resistance to blast will be identified using dominant physiological races of rice blast pathogen in Ningxia through the method of artificial inoculation and natural induction by field identification and disease nursery identification.At the same time,the disease resistance genes were molecular detected using functional markers of disease resistance genes to identifing the Predominant genes and evaluation on its application in Ningxia rice germplasm resources.The results of this study will provide a theoretical basis for the use of cloned rice blast resistant gene for molecular marker assisted selection.It will certainly guide torationally utilize of the existing resistant varieties andbreed new rice varieties with broad-spectrum and long-lasting resistance to blast using molecular methods.The main results are summarized as follows:1、The blast resistance of 183 Ningxia rice germplasm resources was identified.The results showed that most of the tested materials were strong resistance to the tested blast strains.72.13%of the rice materials were moderate resistance,25.14%of the rice materials were moderate susceptibility,and only 1.09%and 1.64%of the materials were resistant and susceptible,respectively.Among them,there were 2 resistant materials,those were Hua 119 and XM-307,and there were 3 susceptible materials,those were Ningjing No.41,Ningjing No.42 and aristateDa huban rice.2、Using functional markers of 8 disease resistance genes to detecte the resistant gene in 183 rice materials.The results showed that the tested materials carrying the resistant gene Pita,Pib,Pikm,Pi9,Pi2,Pi5,Pikh and Pid2 were 168(91.8%),51(27.9%),110(60.1%),59(32.2%),74(40.4%),65(40.4%),65(32.2%),123(67.2%)and 33(18.0%).It was indicated that the blast resistant gene Pita,Pikm and Pikh were relatively widespread in Ningxia ricegermplasm resources.3、Through analyzing the distribution of 8 blast resistant genes in rice germplasm resources in Ningxia,it was found that with the increase of resistance gene loci,the proportion of resistant materials increased and indicated that the resistance of the tested materials increased with the polymerization of resistance genes.However,it is also indicated that the resistant of tested materials was not stronger with the the number of resistant genes increased,such as flower 119.It only contained 2 genes,but the resistance reached the level of resistance;while some other materials contain more numer genes,the resistance is poor,such as Ningjing No.35,which contains 6 resistance genes,but the resistance was expressed in the middle susceptibility.It is indicated that there are dominant resistance genes to blast races in Ningxia area.4、Based on the analysis of rice blast resistance and rice blast resistance genotypes in Ningxia rice germplasm resources,it was found that the materials containing the resistance gene Pi2,Pi5,Pi9 and Pid2 showed better resistance to rice blast.It was indicated that these resistant genes showed major resistance to dominant physiological races of rice blast in Ningxia region and could be considered as major resistance genes.The distribution of these genes in 114 rice varieties in Ningxia show that Pi2 gene were 32.4%,Pid2 were 20.1%,with Pi5 and Pi9 resistance gene were respectively 27.2%.It was further confirmed that the resistance of Ningxia rice varieties can reach the resistance. |
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