Identification On The Species And Pathotypes Of Four Cereal Cyst Nematode Populations From Western And Northern Henan,southern Hebei And Evaluation Of Wheat Cultivars Resistance To Two Populations

Wheat(Triticum aestivum L.)is one of the most important corps in the world. The Cereal Cyst Nematode (CCN) as a most potentially serious constraint to wheat production has become an important disease and cause serious economic losses more and more at present in China. The pathogens cause the disease contain more than 12 species. This article studied the species and pathotypes of four CCN populations from Northwest Henan and Southern Hebei and appraised resistance of the wheat cultivars to Jiaozuo and Puyang populations in the greenroom. The main research contents and results are as follows:Four CCN populations of wheat were collected from Luoyang, Boai, Qingfeng, county in Henan province and Handan county in Hebei province were identified based on morphological and molecular comparisons. The cysts of Luoyang and Boai populations have distinct under-bridge in the vulval cone area, but other two tested populations don't have it. The cysts and the second juvenile main morphological characteristics and measurements of Luoyang and Boai populations conform to Heterodera filipjevi, and the populations from Qingfeng and Handan conformed to H. avenae. The 18S rDNA and 5.8S-ITS rDNA sequences of 4 CCN populations are amplified by polymerase chain reaction (PCR) with the general primers for nematode, and all populations obtain a 1060bp specific fragment. The eight restriction enzymes were used for cutting the ITS-PCR products of four CCN populations. ITS-RFLP analysis showed that the populations from Qingfeng and Handan are identical with the type C of H. avenae, and Luoyang and Boai populations was consistent with the H. filipjevi. Haeâ…¢digested PCR amplified ITS products of H. filipjevi obtained 3 fragments(420, 350, 180bp), but Boai population was digested by Haeâ…¢obtained 4 fragments(550, 420, 350, 180bp). The result of ITS sequences analysis and alignments between Luoyang, Boai populations and related species H. filipjevi from America andItaly was clustered in a same group with close relationship by MP of MEGA 4,and the populations from Qingfeng Handan with the related species H. avenae from Tongzhou and Zhengzhou were clustered in a same group with close relationship. Based on the morphological and molecular characteristics, the Luoyang and Boai populations were identilied as H. filipjevi, other two populations were identilied as H. avenae.The pathotypes of the above-mentioned four populations of CCN were identified by the International Host Differentials Set (IHDS) and a common local cultivar Wenmai 19. The results showed that the pathotypes of these populations are different from ones which have been nominated and reported. Luoyang population and Boai population belong to a same pathotype with coincident virulence to the standard international differential hosts of group A and have a wider virulent range than other populations. The resistance reaction of the standard international differential hosts to above two populations is similar to the"Gotland strain East"which is reported in 1985 by Ireholm in Sweden. The pathotype of Qingfeng population is the same as the pathotype of Handan population, Only La Estanzuela is susceptible to Qingfeng population and resistant to Handan population, all other hosts have the same reaction to both populations. The both populations are avirulence to the barley cultivars with resistance genes Ha1, Ha2 and Ha3. So the pathotype of the both populations should be belong to the first group and named as Ha?1.The resistance of wheat cultivars (lines) which are planted in Northern Huanghuai area and 4 foreign cultivars (lines) to H.avenae Puyang population and H. filipjevi Jiaozuo population were identified and evaluated in the greenroom. The results showed that the resistance between cultivars (lines) were significantly different, but the overall resistance is less. There was no immune and high resistant cultivars in tested 45 cultivars to Boai population, four foreign cultivars (Madsen, VPM, SS679, MILAN) and two domestic cultivars(Zhongyu 6, Pumai 9) were resistant. The identification result of resistance to H.avenae Puyang population showed that there were also no immune cultivars in all cultivars, three foreign cultivars(Madsen, VPM, MILAN) and two domestic cultivars(Xinmai18, Xinmai 19) were the range of high resistant cultivars, accounting for 11.9%, their relative resistance index (RRI) above 0.9; five cultivars(SS679, Pumai 9, Kaimai 18, Luomai 4-168, Zhongyu 6) were the range of resistant cultivars, accounting for 11.9%.