【作者】 李丽华；

【导师】 何中虎； 段霞瑜；

【作者基本信息】 中国农业科学院 ， 作物遗传育种， 2001， 硕士

【摘要】 本研究选用我国北方冬麦区的主栽品种、高代品系和国外抗源共计88份，于1999-00和2000-01年度研究了小麦白粉病的苗期抗性和成株期抗性。苗期选用20个白粉菌株，21个鉴别寄主，根据基因对基因学说推导已知抗白粉病基因。成株期用0～9级法和倒二叶严重度法调查植株叶片发病情况，以病程曲线下面积（AUDPC）、流行速率、倒二叶严重度作为叶片成株期抗性的指标。植株开花10天左右调查穗严重度。根据苗期鉴定和成株期调查结果，了解了我国北方冬麦区的抗白粉病基因，研究了慢病性特征，分析了苗期抗性和成株期抗性的关系，筛选了一批慢白粉病材料。主要结果如下：1.88份参试品种基因推导结果表明，我国北方冬麦区高代品系主要含Pm2、Pm4a和 Pm4b，系谱分析表明，这些基因来源单一。多数主栽品种不含抗白粉病基因，个 别主栽品种含已丧失抗病性的Pm3d、Pm8。2.国外慢白粉病参照品种在本试验中表现晚熟，其田间发病规律与感病品种差异很 大，调查倒二叶严重度比“0～9”级法更能反应慢病性特征。慢白粉病参照品种的 AUDPC＜0.94、R₂＜0.014、倒二叶严重度＜13％。慢白粉病参照品种叶片上病斑菌 丝层薄，对叶片损害小。3.成株期表现不同程度感病的79份参试品种按AUDPC做聚类分析，距离在0.55水 平上，可以明显将这些品种分为4类。第1类品种的AUDPC介于0.21到1.66之 间，包括所有慢白粉病参照品种，因此将慢白粉病指标定为AUDPC＜1.66。4.21个品种符合上述指标，其中13个品种的AUDPC、R₂、和倒二叶严重度值与慢 白粉病参照品种各相应参数很接近，8个品种的各参数值略大，表明发病程度略重。 国内慢病性品种比慢病性参照品种叶片上的菌丝层略厚，但与感病品种仍有显著差 别。另外，小分蘖比主蘖发病重，为避免调查误差，对分蘖少的品种应主要调查主 蘖的严重度。小分蘖发病重也从另一个侧面说明植株营养期长短可能影响抗病性强 弱。兴麦99、CA9550、CA9641含Pm2，可能类似于Bennett提出的背景抗性品种， 另外这些品种叶片上的菌丝层非常薄，而且有轻微的坏死斑。5.感病品种间在AUDPC、R₁、R₂、倒二叶严重度等参数上有很大差别。用倒二叶严 重度调查值计算的AUDPC和用“0～9”级调查值计算的流行速率R1显著相关， 相关系数R=0.499（P＜0.01），因此在筛选慢病性抗源时，对病情上升快的品种， 可以用操作简单的“0～9”级法淘汰感病品种。穗严重度和叶片严重度无相关关系， 应单独调查。 6．比较‘慢白粉病品种和感病品种田间发病情况可以看出，慢病性品种在成株期表现抗 性，与感病品种有明显差别。但以济南门为代表的第2类品种与慢病性品种的差 别较小。系谱分析表明，如果慢病性是由数量性状控制的，两类之间个别品种可能 有一定的遗传关系。 7．比较茁期抗性和成株沏抗性可以看出，苗期鉴定含有厂抗谱基因的品种，成株期被 毒性菌株侵染时，可能表现高感。慢白粉病品种多数不含己知抗白粉病基因，或在 苗期仅对个别菌株表现抗性，但在田间成株期表现发病程度很轻的抗性反应。更多还原

【Abstract】 Eighty-eight wheat varieties and advanced lines from northern China winter wheat region and foreign winter wheat varieties conferring resistant to powdery mildew resistance were used to investigate seedling and adult resistance in 1999-00 and 2000-01. Seedling test was performed with 20 isolates and 21 tester lines carrying known genes. Resistance genes were postulated based on the application of gene-for-gene concept. Adult resistance was recorded with 0? scale method and severity on penultimate leaf method. Adult resistance of leaves were evaluated by area under the disease progress curve (AUDPC), apparent rate, severity on penultimate leaf Spike severity was also collected at about ten days after flowering. The major results are presented below: 1. Gene postulation results indicate that advanced lines in northern winter wheat region mostly carry Pm2, Pm4a and Pm4b. Pedigree analysis shows that these genes have narrow origin. Most cultivars in northern winter wheat region carry no gene or only carry Pm3d and Pm8 which have already lost their resistance. 2. Nine foreign slow-mildewing varieties and advanced lines with very late maturity serve as slow-mildewing checks. Its disease progress pattern is better observed by severity on penultimate leaf method than by ???scale method. Characteristic of such slow-mildewing checks are severity on penultimate leaf less than 13%, apparent rate (R2) less than 0.014, area under the disease progress curve (AUDPC) less than 0.94. Spore density on the leaves of slow-mildewing checks is thin so that the damage to leaves is slight. 3. Seventy-nine varieties and advanced lines apprearing susceptible to E20 isolate on different levels were classified by AUDPC. They can be distinctly classified into four groups. AUDPC for the first group including all the slow-mildewing checks ranged from 0.21 to 1.66. AUDPC<1.66 was therefor used as a criterion for slow-mildewing. 4. Twenty-one variaties conform to that criterion. Thirteen were more or less the same asslow-mildewing checks for such parameters as AUDPC, R2 and severity on penultimate leaves, while the other eight were relatively high. Spore density of native slow-mildewing varieties is slightly thicker than slow-mildewing checks. Small tillers of slow-mildewing varieties are more susceptible than the main tillers so that severity should be collected mainly from the main tillers for those varieties with few small ones. Xingmai 99, CA9550, CA9641 may be backgound resistant varieties proposed by Bennett because they carry Pm2. Spore density on the leaves of these three varieties were very thin with slight necrosis spots. 5. Significant difference was observed among susceptible lines regarding parameters such as AUDPC, R1 and R2. AUDPC calculated from the data by the severity on penultimate leaf method is positively correlated with the apparent rate (R1) calculated from the data obtained by scale method, with the correlation coefficient R=0.499 (P<0.0]). This indicated that susceptible varieties can be discarded if they appear rapid disease developmental progress by the relatively easy scale method. Spike severity and leaf severity do not show significant correlation and they must be investigated separately. 6. Comparison of the disease progress of slow-mildewing varieties and susceptible ones indicate that slow-mildewing varieties were significantly different from susceptible ones because they perform high resistance at adult st更多还原