Screening For Resistant Restorer Lines To Brown Planthopper And Bacterial Blight In Indica Rice And Genetic Analysis Of The Resistance

Based on the completion of identification of resistance to brown planthopper and bacterial blight in indica rice restorer lines, the genetic control and mechanism of the resistance in several restorer lines and their combining ability of yield characters were studied. The main results were as follows:1. Through repeated screening, of the 249 tested materials, 123 resistant lines to brown planthopper were identified, 30 lines with strong resistance.2. Comparison of differential resistance reaction to brown planthopper at maximum tillering stage showed that restorer line Fc598 et al. possessed not only strong antibiosis but desirable non-preference and tolerance as well.3. Testcrosses between Fc598, a highly resistant line to brown planthopper, and the susceptible male sterile (MS) lines, II-32A and Xieqingzao A, were made. The resistance in the derivated progenies from the crosses and their parents as well was determined. The result demonstrated that Fl progeny showed non-full dominate character of resistance and that F2 population displayed double-peaks distribution for the quantities of died tillers of resistant and susceptible lines. X2 prove-test verified that the resistance was controlled by one single dominant gene.4. Restorer line Fc585 also possessed strong resistance to bacterial blight besides to brown planthopper. The hybrid Fl using Fc585 as restorer line showed non-full dominance of the resistance. There existed a double-peak distribution for the quantities of resistant lines and susceptible lines. X2 prove-test verified that resistance to bacterial blight was controlled by one single dominant gene. Meanwhile, resistance level of the MS lines can also significantly influence the resistance performance in hybrid combinations and the derived progenies. Moreover, genetic study on bacterial blight resistance indicated that low level of the resistance in MS lines can also significantly influence the resistance level of the hybrid combinations and the derivated progenies, showing that there existed additive effect caused by minor genes besides the dominant major gene.5. Cross-test displayed that the selected resistant lines all have strong restoring ability to the three different MS lines, Zhengshan 97A, XieqingzaoA and II-32A, withseed-setting rate around 80%. Test of combining ability showed that two resistant lines, Fc560 and Fc589, possessed desirable general combining .ability (OCA). However, most resistant lines showed weak combining ability while suitable for mediate resistance donor for further use.