Abstract: Through marker assisted selection (MAS), four isogenic lines were obtained, which contained both genes qSB9TQ (quantitative resistance to sheath blight) and  TAC1TQ (tiller angle control gene), either of them, and none of them in each background of two  japonica  varieties (Zhenjing 88 and Wulingjing 1). The agronomic traits, yield related components and sheath blight (SB) disease severity of different lines were investigated under three different favorable disease conditions, slight, moderate and severe. Results showed that: 1) In the same background, the lines harboring TAC1TQ showed significantly larger tiller angle than that of lines without this gene, but presenting a consistent phenotype on other agronomic traits. 2) The average SB ratings of the lines showed significant difference among different favorable disease conditions; in slight disease conditions, the four lines showed similar SB ratings with no significant difference, however, in moderate disease conditions, the lines contained both genes showed significantly lower SB ratings than that of the control; in severe disease conditions, the lines with both genes and with qSB9TQ alone all showed significantly lower SB ratings than that of the control, while the lines with TAC1TQ alone had lower SB ratings than that of the control, too, which further confirmed the contribution of qSB9TQ to SB resistance; the negative interaction between TAC1TQ and qSB9TQ on SB resistance was found. 3) In the same disease condition, the lines with different combinations of TAC1TQ and qSB9TQ did not show significant difference on yield related components; along with the increasing SB ratings, the plant yield, seed setting rate and 1000grain weight of all lines declined; the yield per plant of the four lines in severe disease conditions were all significantly reduced compared to those in slight disease conditions, and among them the control lines suffered from the biggest yield decline. Although the potential of TAC1TQ in japonica rice breeding needs further estimation, introducing both genes TAC1TQ and qSB9TQ is benefit to enhance rice SB resistance.

Key words: markerassisted selection, sheath blight, tiller angle, yield

摘要： 分子标记辅助选择获得两个粳稻背景（镇稻88、武陵粳1号）四种基因型（只带有抗纹枯病基因qSB9TQ、只带有分蘖角基因TAC1TQ、同时带有两个基因和两个基因都不带即对照）近等基因系。设置轻发病、中等发病和重发病3种纹枯病发病条件，调查近等基因系基本农艺性状、纹枯病病情及产量性状。结果表明：1）同一背景下，带有TAC1TQ的株系分蘖角度极显著大于不带TAC1TQ的株系，所调查农艺性状基本一致；2）同一基因型株系，不同发病条件下纹枯病病级差异达极显著水平；轻发病条件下，四种基因型纹枯病病情差异不显著，中等发病条件下，同时带有两个基因的株系纹枯病病级显著低于对照，重发病条件下，同时带有两个基因和只带有qSB9TQ的株系纹枯病病级极显著低于对照，而只带有TAC1TQ的株系纹枯病病级显著低于对照，表明qSB9TQ对纹枯病的抗性确实存在，TAC1TQ有利于减轻纹枯病，qSB9TQ和TAC1TQ间有一定的负向互作效应；3）同一发病条件下，四种基因型株系产量性状差异不显著；随着病情加重，单株产量降低，且结实率、千粒重也表现下降趋势。与轻发病条件相比，4个株系在重发病条件下产量均显著下降，其中以对照系减产幅度最大。就增强纹枯病抗性而言，选择qSB9TQ的同时宜选择TAC1TQ，带有TAC1TQ的粳稻品种生产能力有待实践检验。

关键词: 水稻, 分子标记辅助选择, 纹枯病, 分蘖角, 产量