Selection & Analysis Of Three Bacterial Blight Disease Resistance Genes Pyramiding Crossbreed In Rice

Bacterial Blight, caused by Xanthomonas oryzaepv oryzae, as one of the most serious disease to rice, had made great lost on rice production in China. To solve the problem, the best method is breeding new rice species, and to complete several different resistance gene pyramiding is a key step in the whole strategy, though which we can get the useful seed parent within highly resistance, experts had drawn the same conclusion . In the study, we inducedXa-21,Xa-4 andXa-23 into ShuhuiSSl, Mianhui725, Yihuil577, Yihui3551, Yanhui559 and Minghui63 while IRBB60 and WBB1 as the target gene provider. After pyramiding genes analysis and background analysis we got following results:1. We got several Xa-21/Xa-4 gene pyramiding lines including Yihuil577, Yihui3551,Yanhui559 and Minghui63, and the hybrid gene pyramiding lines ShuhuiSSl and Mianhui725 inherent Xa-21/Xa-4/ Xa-23. we also got the lines only within Xa-23 including Yihuil577, Yihui3551,Yanhui559 and Minghui63.2. After different gene transferred into different varieties, they showed different resistance, in general, under the background of Yihui3551, they showed better resistance than others.3. Improved ShuhuiSSl and Mianhui725, inherent Xa-21/Xa-4/ Xa-23, show the great resistance and the lension length was below 1.0 cm , its resistance approach to IRBB60.4. Yihuil577, Yihui3551, Yanhui559 and Minghui63, the lines had been improved which inherent Xa-21/Xa-4 or Xa-21/Xa-23, its resistance also improved prominently and the lension length was 2.0cm or so, and heterozygote or not show the inconspicuous different in disease resistance.5. The disease resistance of the lines within Xa-23/Xa-4 was not better than WBB1 (only inherent Xa-23), it indicated that not all the gene pyramiding can enhance the disease resistance prominently.6 Among the different gene pyramiding lines , anyone inherent Xa-21 can demonstration quite good resistance on Bacterial Blight disease, it showed that the gene Xa-21 was good and efficient, in the later gene pyramiding we should select the one inherent Xa-21 first of all.7. Analysis indicated that the background similarity between the selected lines and backcross parent was 90%.