| In the present study, rice variety WBB1 containing bacterial blight resistant gene Xa23 was crossed with the restoring lines containing the other blight resistant gene Xa4 and rice varieties with different genetic backgrounds respectively. In the F1 and F2 generations, the Xa23/Xa4 polymers were determined by SSR marker. The dominant character and resistant spectrum were observed by inoculating bacterial blight (BB) strains. The tested results were as follows.1. According to the results observed after inoculating the bacterial blight strains C1-C7, the lension length in the Xa23/Xa4 polymers was below 1.0 cm, realizing the level of high resistance. The resistant level was higher than that of Xa4.2. The dominant level of Xa23 gene was different in different genetic background. In the F1 populations of Indica×WBB1 and Japonica×WBB1, the resistant level reached high resistance, showing high dominance, but it only reached moderate resistance in the F1 progenies of sterile line×WBB1, showing moderate dominance.3. According to the results observed after inoculating bacterial blight strains C1-C7 and the high poisonous strain P6, the Xa23 gene showed wild resistant spectrum.4. The SSR marker RM206 closely linked to Xa23 was used for determinating the Xa23/Xa4 polymers in this study, and the results showed a good polymorphism and accuracy in the parents and hybridization progenies. In the F2 progenies of Gui99×WBB1, R402xWBBl and IR30xWBBl, the MAS efficiencies of RM206 were 97%, 96% and 98%, respectively. The results indicated RM206 should be a promising marker for the molecular assisted selection breeding for the Xa23 gene.5. In anther culture, the green plants were obtained only from the combination Gui99×WBB1, which showed a high callus induction rate. The suitable culture medium for green plant differentiation was N6 + KT2.0 + IAA1.0.6. By using the techniques of molecular marker and anther culture, the homozygote and F3 materials of Xa23/Xa4 polymer were obtained. |
