不同遗传背景籼稻Xa23基因品系的白叶枯病抗性筛选和评价

【目的】系统比较分析含Xa23基因的籼稻品系白叶枯病抗性，为白叶枯病抗性育种及水稻白叶枯病防治等提供种子资源，同时为白叶枯病分子抗性育种提供参考。【方法】以14种遗传背景不同且含有Xa23基因的81份籼稻品系为材料，孕穗期采用剪叶接种法接种7种南方稻区白叶枯病生理小种代表菌株（FuJ、YN24、HNA1-4、GDA2、PXO86、GD1358和PXO99），接种20 d左右当参试材料的病情趋于稳定时，量取病斑长度，鉴定参试材料的抗病性。【结果】供试材料对7株白叶枯病菌菌株的抗感分析结果显示，81份品系中有74份品系对7株白叶枯病菌菌株均为抗病，其中35份品系对所有菌株为高抗；含Xa23基因品系对7株白叶枯病菌菌株的抗性频率大小为:PXO86和YN24（100.0%）>GD1358和HNA1-4（98.8%）>PXO99（96.3%）>GDA2（95.1%）>FuJ（93.8%）；同一遗传背景品系对7株白叶枯病菌菌株病斑长度的变异系数在100.0%以上的有遗传背景为A、B、C、E、F和H类品系对菌株FuJ，遗传背景为A、B、D和E类品系对菌株GDA2，遗传背景为A类品系对菌株GD1358和HNA1-4，遗传背景为A和B类品系对菌株PXO86、PXO99，遗传背景为A、C和E类品系对菌株YN24；对14种遗传背景不同品系白叶枯病抗性的方差分析结果表明，不同来源含Xa23基因的品系与7株白叶枯病菌菌株间病斑长度均无显著差异（P>0.05）；对含Xa23基因的品系在7株白叶枯病菌菌株诱发下的菌斑长度的相关性分析结果表明，菌株GD1358、HNA1-4、PXO86和YN24与对应的其他菌株间呈显著（P<0.05）或极显著（P<0.01）正相关。【结论】在白叶枯病抗性研究时选用菌株GD1358、HNA1-4、PXO86和YN24其中1种抗源接种试验材料，即可得到较宽抗谱的抗性材料，提高育种效率。

Screening and evaluation of resistance of Xa23 gene line in Indica rice varieties with different genetic backgrounds against bacterial blight

【Objective】This study comparatively analyzed bacterial blight resistance of Indica rice line with Xa23 gene, provided germplasm resources for bacterial blight resistance breeding and prevention, and meanwhile provided reference for molecular breeding of bacterial blight resistance.【Method】The 81 Indica rice cultivars with Xa23 gene in 14 genetic backgrounds were used as materials, were inoculated with 7 widely used bacterial blight pathogens(FuJ, YN24, HNA1-4, GDA2, PXO86, GD1358 and PXO99) at booting stage in southern rice areas, measured the lesion length and estimated the disease resistance of the cultivars when the condition of the materials tended to be stable after about 20 d.【Result】Study result of disease resistance and susceptibility about 7 bacterial blight pathogens showed that the 74 rice cultivars among 81 materials had strong resistance to 7 bacterial blight, 35 cultivars of that were HR(high resistance). The resistance frequency of the lines with Xa23 gene against the 7 pathogens were PXO86 and YN24(100.0%) >GD1358 and HNA1-4(98.8%) >PXO99(96.3%) >GDA2(95.1%) >FuJ(93.8%).The coefficient variation of the cultivars with the same genetic background against the lesion length of the 7 bacterial blight pathogens were more than 100%:the FuJ induced the cultivars of genetic background A, B, C, E, F and H, the GDA2 induced the cultivars of genetic background A, B, D and E, the GD1358 and HNA1-4 induced the cultivars of genetic background A, the PXO86 and PXO99 induced the cultivars of genetic background A and B, the YN24 induced the cultivars of genetic background A, C and E. Variance analysis of bacterial blight resistance of the14 genetic backgrounds showed that no significant difference in the lesion length between the lines with Xa23 gene and 7 bacterial blight pathogens(P>0.05, the same below). The correlations of the lesion length of lines with Xa23 gene induced by 7 bacterial leaf blight pathogens showed that there were significant difference or extremely significant(P<0.01) positive correlation between the strains GD1358, HNA1-4, PXO86 and YN24 with corresponding to the other 6 pathogens.【Conclusion】One of the GD1358, HNA1-4, PXO86 or YN24 are selected for the study of bacterial blight resistance, the resistant materials with widely resistance spectrum can be obtained, that can improve breeding efficiency.