Identification And Study On The Diversity Of Insect Resistence Markers Of Soybean Germplasm Resources For Resistance To Common Cutworm(Spodoptera Litura)

Soybean（Glycine max（L.）Merr.）is one of the most important cultivated crops in the world and is the main source of plant protein and oil for humans.However,diseases and insect pests such as Spodoptera litura,Lamprosema_indicata Fabricius and SMV have seriously affected the growth and development of soybean,resulting in reduced yield and decreased quality.Therefore,it is necessary to strengthen the management of pests and diseases of soybean.Breeding resistant soybean germplasm requires accurate phenotypic identification of disease and insect resistance with special test conditions and large amount of work.With the help of polymorphism of molecular markers among resistant and susceptible varieties,genotypic identification of tested varieties is carried out to select disease and insect resistant varieties.This method is more convenient and fast than traditional phenotypic identification.In this thesis,the larvae weight as antibiosis indicator of Spodoptera litura on the sixth,ninth and twelfth days of treatment were used.At the same time,the differences of resistance to Spodoptera litura among Soybean Germplasms from different ecological regions were evaluated,and a number of insect-resistant varieties were selected according to the sources of ecological regions.The SMV resistance was evaluated by the disease index of soybean V4,V6 and R1 stage.The polymorphism differences of disease and insect resistance markers among different soybean materials were analyzed and evaluated,and polymorphic markers for resistance classification of soybean resources against pests and diseases were selected.The main results are as follows:（1）Antibiosis resistance of soybean resources to Spodoptera litura:Through the summer sowing of soybean resources in summer 2017 and spring sowing in 2018,the antibiosis identification of Spodoptera litura was found to have the highest F value on the 12th day of feeding.Moreover,this study indicating that compared with the sixth day and the 9th day,the difference between the different varieties was most significant on the 12th day of feeding.The covariance analysis of larvae on the 6th,9th and 12th day of the two years showed that the difference in the weight of the larvae of Spodoptera litura at the same feeding days for two years reached a very significant level.Through the correlation analysis between different feeding days in two years,it can be found that correlation between the different feeding days of the same batch,the same feeding days of different batches,and the different feeding days of different batches of the larvae of Spodoptera litura are reaching the extreme.Significant levels indicate that the resistance of different species to Spodoptera litura is stable.（2）Differences in antibiosis resistance between soybean germplasm from different ecology region and selection of insect resistant resources:The number of insect-resistant varieties in soybean germplasm in the North Eco-region is the highest,accounting for 72.3%of the total ecological area;the highest number of soybean germplasm in the Huanghuaihai Eco-region is the medium-resistant variety,accounting for 43.8%of the total ecological material;The number of susceptible species in the Middle and Lower Yangtse River Eco-region germplasm was the highest,accounting for 43.2%of the total ecological material.Insect-resistant varieties were screened out in different ecological regions,including KeC14-732,Jinyuan 71,Ha12-3510,Heihe 35 and Ha13-2413 in North Ecoregion;Shangdou 066,Jidou 21,Jidou 12,Longzhong Huang601 and Shanning 18 in Huanghuaihai Eco-region;Zhexian 9,Nannong 415,Nannong 38,Nannong 43 and Zhexian 8 in the Middle and Lower Yangtse River Eco-region.（3）Identification of soybean resistance to SMV:It was found that,the disease resistance index of soybean varieties gradually decreased with the change of growth period.The soybean resources in different ecological regions in each survey period have significant differences in SMV resistance.In contrast,the soybean varieties in the North Eco-region and the Huanghuaihai Eco-region are more resistant to SMV than the soybean varieties in the Middle and Lower Yangtse River Eco-region.Based on the weighted average of the three periods,most of the soybean resources in the North Eco-region are medium-resistant and medium-sensitive.Most of the soybean resources in the Huanghuaihai Eco-region are medium-sensitivity and high-sensitivity,and most of the materials in the Middle and Lower Yangtse River Eco-region are high-sensitivity.（4）Selection of soybean germplasms resistant to Spodoptera litura and SMV:27 soybean germplasms resistant to Spodoptera litura and SMV,such as Zhongke Maodou 1,Liaoqingdou 1,Shangdou 066,Jihei 4,Jiyu 109,Jilin Xiaogudou 7,Jimidou 3,Jiyu 72,Jiyu 401,Heihe 49,Heihe 35,Heihe 43 and Heihe 44.（5）Diversity and effectiveness evaluation of insect-resistant markers:The phenotype of larval weight was combined with the genotypes of SSR markers Sat₂58,Satt175,Satt702,Satt323,Satt626,Satt536 and PAV markers Gm07PAV0595,Gm07PAV0389 linked to the insect-resistant QTL.It was found that there were significant or extremely significant differences in larval weight between the different genotypes of Satt323,Satt626,Satt536,Gm07PAV0595,Gm07PAV0389.The allelic variation Satt334216 bp,Satt626-283 bp,Satt626-271 bp,Satt536-166 bp,Gm07PAV0389-787 bp and Gm07PAV0595-1463 bp are allelic variation for insect resistance,which can be used to screen insect-resistant germplasm;allelic variation Satt702-285 bp,Gm07PAV0389-962 bp and Gm07PAV0595-750 bp are allelic variation for insect susceptibility,which can be used to eliminate the germplasm of the insects.The efficiency of identification can be improved by simultaneous identification of multiple molecular markers.Compared with SSR markers,PAV markers are easier to distinguish between soybean germplasm resources and are more ideal marker types for molecular marker-assisted identification of germplasm resources.（6）Evaluation of the diversity and effectiveness of anti-SMV markers:The genotyping with the SSR markers Satt334,Satt634,Satt266,Sat₂46,and Satt286 linked to the anti-SMV gene combined with the disease index showed that there were significant or extremely significant differences between the phenotypes.Furthermore this information indicating that Satt334,Satt634,Satt266,Sat₂46,and Satt286 can be used to classify the resistance of soybean germplasm to SMV.The allelic variation Satt334-216 bp,Satt286204 bp and Sat₂46-225 bp can be used to screen disease-resistant germplasm;the allelic variation Satt634-102 bp and Satt266-106 bp can be used to screen susceptible germplasm.