Investigation Of Heterodera And Pratylenchus Species Co-Infection On Wheat In Huanghuai Area And Their Infection Dynamics In Wheat Field

Cereal cyst nematodes(CCN)are important plant parasitic nematodes seriously damaing wheat production in China.During our field survey,the co-infection of root-lension nematodes(Pratylenchus spp.)with CCN species was found occurring commonly in wheat field.In this study,the co-infection of Heterodera and Pratylenchus on wheat from Jiangsu,Henan and Anhui provinces in Huanghuai Region was surveyed,the co-infection dynamics of H.avenae and P.neglectus in wheat field from Peixian County,Jiangsu Province was investigated,and the effectively accumulated temperature model of H.avenae was established.The mian results are as the following:Twenty-five samples were collected from wheat fields in three provinces,and the co-infection species of Heterodera and Pratylenchus were molecular detected.The species detection by the duplex PCR showed that nine out of eleven samples from Henan Province were H.filipjevi,one sample was H.avenae,and one sample was the mixed populations of two species.The H.filipjevi is the dominant species in Henan wheat growing areas.Seven out of ten samples from Anhui Province were H.avenae,one sample was H.filipjevi,and two samples were the mixed populations.Four samples from Jiangsu province all were H.avenae.The H.avenae is the dominant species in wheat growing areas of Anhui and Jiangsu provinces.The Pratylenchus nematodes were extracted from sixteen out of twenty-five samples.The species detection by the multiplex PCR showed that three out of seven samples from Henan Province were P.neglectus,four samples were the mixed populations of P.neglectus and P.coffeae.Four out of seven samples from Anhui Province were P.neglectus,three samples were the mixed populations of P.neglectus and P.coffeae.Two samples from Jiangsu province both were P.neglectus.The P.neglectus is the dominant species in wheat growing areas of Huanghuai Region.The co-infection of H.avenae and P.neglectus were found in wheat fields of Jiangsu Province,while the co-infection of four species including H.avenae,H.filipjevi,P.coffeae and P.neglectus,were found in wheat fields of Henan and Anhui provinces.During October 2018 to June 2019,the soil temperature and the infection dynamics of H.avenae and P.neglectus in wheat field from Peixian County,Jiangsu province,were investigated systematically.The results showed that the average soil temperature ranged from 1.5? to 16.8?,presenting a dynamics of "V" type during the whole growing season of winter wheat.The hatching of second-stage juveniles(J2)of H.avenae in rhizosphere soil of wheat showed a dynamics of "M" type,presenting two hatching peaks which appeared in late December and early March of the following year,respectively.The peak of J2 infection to wheat root also appeared in early March.The population peaks of the third-stage juveniles(J3),the fourth-stage juveniles(J4),and the white females appeared in the root system in early April,late April and mid May,respectively.Two peaks of P.neglucts infection to root system appeared in early January and early April,respectively,and a peak of P.negluctus populaitons appeared in soil in early May.The data for soil temperature and the dynamics of different developmental stages of H.avenae inside root during four growing seasons of winter wheat in Peixian County were analysized according to the rules of effectively accumulated temperature.The effectively accumulated temperature of K value for J2 was calculated as 105.80 d·?,and the developmental starting temperature of C value was 2.45?.The linear regression equation for the developmental rate of J2 and the soil temperature is V=0.03821T-0.2714(r=0.90).The K value for J3 was 120.56 d·?,and C value was 3.74?.The linear regression equation for the developmental rate of J3 and the soil temperature is V=0.007973T0.02886(r=0.98).The K value for J4 was 25.09 d·?,and C value was 7.25?.The linear regression equation for the developmental rate of J4 and the soil temperature is V=0.007631T-0.01386(r=0.98).The results showed that there is a positive correlation between the develpmental rate of J2,J3,and J4 of H.avenae and the soil temperature,respectively.The resultes obtained in this study provide theoretical support for the intergrated management of nematode diseases in wheat root,and it is of great significance to protecting grain production in China.