Pyramiding Breeding Of Genes For Diseases And Pest Resistances Based On SSSLs In Rice (Oryza Sativa L.)

Rice is one of the most important food crops in the world.Rice blast,Bacter ial leaf blight and Brown planthopperare the three common diseases and insect pests to affect the yield and qualityof the rice,and which reduce theproductionof the rice seriously.Now,Scientists has made great progress in rice breeding of resistance disease and insect pestfrom all over the world.Thelong-term practice provedthat using marker-assisted selection technology pyramiding multiple resistance genes to cultivate rice varieties has a broad spectrum and durable resistance to prevent and control the rice diseases and insect pests is the most cost-effective way.Used thebuilt single segment substitution lines,this research maindly mapped resistant disease and insect pestsgene s,and builtmuch more resistance pyramiding lines simultaneously,by the SSSLs and pyramiding lines.The results were as followed.1.25 pyramiding lines and 1 single segment substitution lines materials with rice blast resistance gene q BLAST-11-1were usedin the research.The rice blast resistance gene q BLAST-11-1which came from the donor parent,Lemont(W23)was mapped at the same position with Pik-m,one of which cloned on chromosome 11.Natural evaluation test indicated that all the pyramiding lines containing rice blast resistance gene,q BLAST-11-1reached 1 or 2 level with the leaf blast resistance and 1 or 3level with the panicle resistance blast.Most of the homozygous materials showed resistance to rice blast.2.16 homozygous pyramiding linesmaterials were obtained in 2016 early season through16 different heterozygous pyramiding lines materials and 7 differenthomozygous pyramiding linesmaterials,which carried the bacterial leaf blight resistance genexa5,Xa21.Bacterial leaf blight resistance tests showed thatfive physiological races of bacterial leaf blight reached medium resistance level and above for the pyramiding lines materials containing xa5.And the pyramiding lines materials containing Xa21 also reached medium resistance and abovelevel for all physiological races of bacterial leaf blight except for physiological races I Vand V.The leaf blight of five physiological races of resistance has reached a high level for the pyramiding lines material which contained both of genes xa5?Xa21.3.Linkage analysis indicated that the Bph24 locus may existed two or above genes commonly controlling rice BPH resistance.Rice BPH resistance tests showed thatthe materials which carried rice BPH resistance genes Bph24 or both Bph24 and Bph14 was as the same resistance level as the donor parent,T499,while the materials which contained rice BPH resistance genes Bph14 showed very low resistance level,just as the control HJX74.Therefore,Bph24,a Brown plant-hopper resistance gene,was of great value in the resistance breeding.In this research,marker-assisted selection technique was appliedto the polymerization breeding related with the rice blast resistance genes,bacterial leaf blight genes and Brown plant-hopper resistance.It is the purpose of improving the disease and insect resistance of superior varieties.Resistance tests showed that the constructed new lines in resistance to disease and insect pest have a big ascension,and basically achieved thepurpose of the pyramiding genes of disease and insect pests.