Identification Of Species And Pathotypes Of Four Cereal Cyst Nematode Populations From Shandong, Henan And Anhui Contiguous Areas And Resistance Evaluation Of Wheat Cultivars To Huaiyang Populations

The Cereal Cyst Nematode(CCN)is worldwide distribution of parasitic nematodes of wheat. It has become one of the most important problem to the Huanghuai wheat plant area in recent years in China. Wheat is one of major cereal crops in the contiguous areas of Henan, Shandong and Anhui province. The CCN has been constituted a serious threat to the local wheat's produce. Planting resistant cultivars is the most economic mothed to control this disease. The CCN has 12 valid and several indefinite species, and has 15 pathotypes which have been nominated and reported in the world. To identify species and pathotypes of the CCN is the groundwork of screening and breeding resistant cultivars. This research have identified species and pathotypes of 4 CCN populations from the contiguous areas of Shangdong, Henan and Anhui province, and evaluated the resistance of major wheat cultivars which were planted in this area to Huaiyang population of Heterodera filipjevi. The main research contents and results as follows:This species of 4 CCN populations from Zhoukou Huangyang, Shangqiu Suiyang, Heze suburb and Fuyang Yingshang were identified based on morphological and molecular methods. The results showed that the cysts of Huaiyang population have the distinct underbridge in the vulval cone area, but other three populations have no underbridge. The main morphological characteristics and measurements of cysts and the second juvenile of Huaiyang population accord with H. filipjevi, while the other three populations accord with H. avenae.The ITS-PCR products of four CCN populations digested by 8 restriction enzymes (TaqⅠ, AluⅠ, HaeⅢ, HinfⅠ, RsaⅠ, PstⅠ, CfoⅠ, Tru9Ⅰ) then we could observe the fragments obtained were the same of Shangqiu, Heze and Fuyang populations which accord to H. avenae type C , but different from Huaiyang population digested by TaqⅠ, PstⅠand Tru9Ⅰ. The fragments of Huaiyang population accord to H. filipjevi. TaqⅠdiggested PCR amplified ITS products of Huaiyang population obtained 3 fragments (350bp, 300bp, 150bp), but the other 3 populations obtained 3 fragments(400bp, 300bp, 150bp). PstⅠdigested PCR amplified ITS products of 3 populations (Shangqiu, Heze and Yingshang) obtained 2 fragments (713bp, 350bp), while Huaiyang population obtained 3 fragments (713bp, 213bp, 130bp). Tru9Ⅰdigested ITS products of the 3 populations yielded 3 fragments (560bp, 320bp, 200bp) while Huaiyang population yielded 2 fragments (560bp, 500bp). The results of rDNA-ITS sequence clustering analysis showed that Shangqiu, Heze and Fuyang populations might be type C of H.avenae and have a close relationship with H. australis. The sequence of Huaiyang population was clustered in a same group with H. filipjevi. By these researches we found Huaiyang population are according with H. filipjevi, and the other 3 populations are according with be type C of H.avenae.The pathotypes of the four CCN populations were identified by 23 standard international host differentials set and a local cultivar Wenmai 19. The results showed that the pathotypes of these four populations are different from anyone which have been nominated and reported. Heze suburb population and Fuyang Yingshang population belong to a same pathotype with coincident virulence to the standard international differential hosts of group A. The resistance reaction of the standard international differential hosts of group A to Shangqiu Suiyang population is similar to above two populations, with 13 accordance in 14 differential hosts, but wheat cv. KVL191 is resistant to Heze suburb population and Fuyang Yingshang population, and Shangqiu Suiyang population are virulent on this cultivar. Nevertheless, Zhoukou Huaiyang population has a wider virulent range then other three populations; most of 23 standard international differential hosts is susceptible reaction to it, but oat cv. A.sterilis I.376 and wheat cv. La Estanzuela and Harlan 43 are resistant reaction. Local wheat cv. Wenmai 19 was found to be susceptible to all of the four populations.The resistance of wheat cultivars including 41 domestic cultivars which are planted in the Huanghuai wheat plant area and 5 foreign cultivars for additional by J2 inoculation in greenhouse at about 15℃. The results showed that there was no immune cultivars in tested. The most susceptible cultivar is a domestic cultivar Yumai49-198 and take it as check to calculate the relative resistance index (RRI) of the others cultivars. Two foreign cultivars (Madsen and VPM) are the range of high resistant cultivars have less then 5.0 cysts/plant on the face of roots,with RRI above 0.90 and accounting for 4.3% rate in all tested cultivars. Four cultivars(Xinmai19, 04zhong36, Zhoumai23 and Hengguan35) are the range of resistant cultivars, with RRI between 0.70 and 0.89 and accounting for 30.4% in all tested cultivars. Fourteen cultivars (Tongzhoumai916, Xinmai18, Fumai936, Taikong6, et al.) are the range of moderately susceptible cultivars, with RRI between 0.50 and 0.69 and accounting for 30.4% in all tested cultivars. Eighteen cultivars are the range of susceptible cultivars, with RRI between 0.30 and 0.49 and accounting for 39.1% in all tested cultivars. The others eight cultivars are the range of high susceptible cultivars, average number of cysts of single plant more than 30, with RRI under 0.30 and accounting for 17.4% in all tested cultivars.