Genetic Diversity Ananlysis Of Two Maize Leaf Spot Pathogens And Resistance Identification Of Maizecultivars In Henan Province

Maize southern leaf blight and Maize Curvularia leaf spot are two worldwide diseases that occur on corn.These two diseases are common in Henan Province,and Maize Curvularia leaf spot has a tendency to worsen year by year,causing great harm to corn production.In this study,samples were collected from the northern,eastern,southern and central Henan provinces in September 2018,and they were isolated,purified and identified to identify the pathogens of Maize southern leaf blight and Maize Curvularia leaf spot.ISSR technique was used to analyze the genetic diversity of Bipolaris maydis(B.maydis)isolated from Maize southern leaf blight and Curvularia lunata(C.lunata)isolated from Maize Curvularia leaf spot,and selected some resistant germplasm resources.The main research results are as follows:1.A total of 151 strains were isolated from Maize southern leaf blight samples and identified as B.maydis.A total of 154 strains were isolated from Maize Curvularia leaf spot samples and identified as C.lunata.2.the ISSR primers were used to amplify the isolated Bipolaris maydis(B.maydis)and Curvularia lunata(C.lunata).the statistical data were processed by POPGENE,NTSYS and other software to analyze their genetic diversity and genetic relationship among populations.The results of the analysis of B.maydis showed that the most abundant genetic diversity was found among the B.maydis in central Henan,while the lowest genetic diversity was found among the B.maydis in southern Henan.The genetic relationship between the populations of B.maydis in central and eastern Henan was the closest,and the genetic relationship between the populations of B.maydis in southern and eastern Henan was the farthest.Using NTSYS software for cluster analysis,the four geographical groups are divided into three groups.The first group is in the northern part of Henan Province,the second group includes the eastern and central parts of Henan Province,and the southern part of Henan Province is the third group.The analysis results of C.lunata showed that the genetic diversity among C.lunata strains is the most abundant in northern Henan,and the genetic diversity among C.lunata strains is the lowest in central Henan.The genetic relationship between C.lunata populations in northern and eastern Henan was the closest,and the genetic relationship between C.lunata populations in southern and eastern Henan was the farthest.Using NTSYS software for cluster analysis,the four geographical groups are divided into three groups,the first group includes the northern and eastern areas of Henan,the second group is the central area of Henan,and the south area of Henan is the third group.3.The results of disease resistance identification of 94 introduced varieties showed that the varieties with high resistance to Maize southern leaf blight were Tiantai 366,Longsheng 3 and Longsheng 209,accounting for 3.19%of the identified varieties.22 varieties such as Nongdan 476,Tianhua 001 and Jiahua 909 showed disease resistance,accounting for 23.40%of the identified varieties.Li Yu 151,Hong Rui 101,Ji Nong 321 and other 47 varieties showed moderate resistance,accounting for 50.00%of the identified varieties.Mengyu 306,Wugu 631,Hongrui 158 and other 16 varieties were susceptible,accounting for 17.02%of the identified varieties.Jiyu 517,Shandan 638,Shandan 618 and other 6 varieties showed high sensitivity,accounting for 6.38%of the identified varieties.There are no varieties with high resistance to Maize Curvularia leaf spot.Fuyu 88,Xiangeng 303 and Dongdan 2184 showed disease resistance,accounting for 3.19%of the identified varieties.Hongrui 158,Jinong 366,Jinong 367 and other 20 varieties showed moderate resistance,accounting for 21.28%of the identified varieties.Annong 9,Tianhua 001,Jiahua 909 and other 43 varieties were susceptible,accounting for 45.74%of the identified varieties.28 varieties such as Jinong 802,Sanbei 63 and Fuyu 69 showed high sensitivity,accounting for 29.79%of the identified varieties.4.The results of disease resistance identification of 117 regional test varieties showed that DH682,Kang Rui 108 and Fu Rui 6,which accounted for 2.56%of the identified varieties,showed high resistance to Maize southern leaf blight.Huaiyu 68,Ruibang 16,Mingyu 3 and other 28 varieties showed disease resistance,accounting for 23.93%of the identified varieties.Jin Liang 516,Xiangyu 683,Junyan 0998 and other 49 varieties showed moderate resistance,accounting for 41.88%of the identified varieties.29 varieties such as Jiayu 34,Xiangnong 16 and Yu 'an 006 were susceptible,accounting for 24.79%of the identified varieties.Eight varieties,GX26,Jinbei 126 and Dedan 142,showed high sensitivity,accounting for 6.84%of the identified varieties.There are no varieties with high resistance to Maize Curvularia leaf spot.Simon 3358,Xianyu 1773,Gaoyu 66 and granong 16 showed disease resistance,accounting for 3.42%of the identified varieties.41 varieties such as Jin Liang 516,Huaiyu 68 and Ruibang 16 showed moderate resistance,accounting for 35.04%of the identified varieties.54 varieties such as DH682,Fu Rui 6 and HY107 were susceptible,accounting for 46.15%of the identified varieties.18 varieties such as Yuxing 198,Jingyu 787 and Jiayu 34 showed high sensitivity,accounting for 15.38%of the identified varieties.