中文摘要：

为了解当前大面积种植小麦品种及种质资源对小麦黄矮病（BYDV）的抗病性,在利用自然发病和人工接种的方法对小麦抗病性进行鉴定的基础上,构建了可同时检测病原BYDV三个不同种群的多重PCR体系,并检测了陕西省杨凌地区的种群发生状况以验证体系的稳定性。结果表明,2007年田间BYDV自然发病率高达86.5%,2008年和2009年发病率降低,分别为10.6%和14.0%,不同年份间自然发病率差异大。2009年在自然发病的基础上进行人工接种鉴定,发现品种和资源发病率较自然发病率升高43.7个百分点,而已感病材料的发病率变化不大。小冰麦×小偃22（F1）、小偃22×小偃6号（F1）、石5144×小偃22（F2）等分离群体和小冰麦、豫麦34等小麦品种部分植株感病初期发病级别分别达到3、2、5、5、6级,而后期级别分别降至0、0、1、2、0级,表现出恢复现象。小偃6号、小偃54、小偃597等小偃系列品种发病率高,2009年人工接种后小偃系列品种发病率高达总调查材料数（157种）的13.5%。秦丰148、西农402、陕715、西农979四个品种连续三年表现抗病。利用多重PCR体系检测了杨凌地区的8个田间自然发病样品,发现混合感染现象严重,PAV感染率达到25%,也证明多重PCR体系稳定可靠。

英文摘要：

The methods of strip cropping and artificial inoculation were used to investigate the natural resistance to wheat yellow dwarf virus（BYDV） of different wheat varieties from national wide and determinate the prevalent population of BYDV in the field of Yangling of Shaanxi province.A multiplex PCR system was established to detect BYDV population in Yangling,which can detect BYDV popula-tion -GPV,GAV and PAV simultaneously.The results showed that the morbidity of BYDV in 2007 reached up to 86.5%,while it reduced to 10.6%and 14%in 2008 and 2009,respectively.A second survey was did and the morbidity increased largely while it changed little in some varieties been infected after the artificial inoculation.Several segregation population or varieties,such as Xiaobingmai×Xiaoyan 22（F_1 generation）,Xiaoyan 22×Xiaoyan 6（F_1 generation）,Shi 5144×Xiaoyan 22（F_2 generation）, Xiaobingmai and Yumai 34 showed a recovery phenomenon,disease degrees of some of their plants reduced from 3,2,5,5,6 to 0,0,1,2,0 at early and late stages,respectively.Qinfeng 148,Xinong 402,Shaan 715 and Xinong 979 showed resistance to BYDV in successive 3 years,while several strains of Xiaoyan,such as Xiaoyan 6,Xiaoyan 54,Xiaoyan597 showed high susceptibility.The morbidity of Xiaoyan after artificial inoculation account for 13.5%of all the 157 varieties or strains.Eight samples from Yangling infected by BYDV were successfully verified with multiplex PCR system,the phenomenon of mixed infection was heavy,the infection rate of PAV is 25%,and the measured results indicated that the system was stable and reliable.