Improvement Of Brown Planthopper Resistance Of Rice Restorer R666 By Marker Assisted Selection

Brown planthopper(Nilaparvata lugens)(BPH) is one of the major pests which decrease the yield in the production of rice around the world, especially in Asia. With the gradual development of molecular marker technology, gene selection breeding for resistance has already become the main breeding method. With the new method, we could develop the resistant varieties to control the infestation of BPH timely and effectively.R666 is an elite lodging-resistance restorer line of two-line hybrid rice. All the hybrid combinations in which R666 was used as male parent showed lodging resistance, high quality and high yield, but susceptible to BPH. In this study, we introgressed two BPH-resistance genes, Bph14 and Bph15, into the genetic background of R666 by using molecular marker assisted selection(MAS), backcrossing and phenotypic selection. Through the identification of resistance to BPH, the investigation of main agronomic traits and combining ability analysis, we have got some resistant breeding lines and hybrid combinations. The main results are as follows:1. Fifteen homozygous lines with the two resistance genes(Bph14 and Bph15) were obtained and the result of identification of resistance to brown planthopper showed that the resistance level of three, breeding lines JQ13001-46-34-5, JQ13001-46-45-4 and JQ13002-6-11 reached resistance(R), the resistance level of other, breeding lines JQ13001-46-34-4, J13001-31-23 and JQ13002-6-16 reached moderately resistance(MR). According to the identification of resistance to brown planthopper, the investigation of main agronomic traits and combining ability analysis, we generally selected three excellent breeding lines: JQ13001-46-34-5, JQ13001-46-45-4 and JQ13002-6-11.2. Forty five crosses were made from fifteen selected breeding lines and six thermo-sensitive genic male sterile lines. The results of identification of BPH resistance at seedling stage showed that the combinations with homozygous Bph14 and Bph15, i.e. the two parents had homozygous Bph14 and Bph15, were resistant against BPH. The resistance score of Hua1165S/JQ13001-46-45-10 was 1, reached highly resistance(HR). The resistance score of other five combinations was 3, reached resistance(R) levels. Eleven combinations were moderately resistant(MR) BPH. The seedling of combinations with heterozygous Bph14 and Bph15, i.e., one of two parents had no Bph14 and Bph15, were susceptible to BPH.3. The main agronomic traits, yield and rice quality of the selected fifteen breeding lines and their derived forty five combinations were investigated. The results indicated that most of breeding lines were similar to R666 except of several traits. Synthesizing the results of BPH resistance, the main agronomic traits, yield and rice quality, six combinations, Hua1165S/JQ13001-46-34-5, Hua1165S/JQ13001-46-45-4, Hua1165S/JQ13001-9-79, Hua1165S/JQ13001-26-32, Hua1165S/JQ13002-6-11 and Luohong 4A/JQ13002-25-29 were promising. These combinations were needed to evaluate the application value in production in future.