Isolation And Identification Of Representative Anthracnose Strains And Construction Of Applied Core Germplasm In Jute(Corchorus Spp.)

Jute,an annual herb of the genus Corchorus in Malvaceae,is one of the most important bast fiber crops in the world.Anthracnose seriously affects the yield and quality of jute fiber.It can be effectively controlled by making clear the species of the pathogen of anthracnose,which will facilitate controlling this disease resistance.It is necessary to construct a batch of excellent applied core germplasm,which will promote jute genetic breeding,mine excellent genes and improve fiber production.In this study,we constructed a batch of core germplasm for jute application,isolated and identified the pathogen samples of jute anthracnose collected from the main jute producing areas of China,and evaluated the resistance of jute germplasm resources.Then,we constructed the DNA molecular identity card of applied core germplasm by SSR fluorescence labeled capillary electrophoresis.The main results are as follows:1.Based on the isolation and identification of 92 strains of jute anthracnose in China,11 representive strains were selected for gene sequence analysis of r DNA-ITS and LSU regions.Phylogenetic tree indicated that the strains of ZZ4,GX19,et al are Colletotrichum gloeosporioides and the CS3 strain is Colletotrichum dematium.The main pathogens of anthracnose in the main jute producing areas of China in recent years are Colletotrichum gloeosporioides and Colletotrichum dematium at the molecular level.2.In order to determine the pathogenicity of these 11 representive anthracnose pathogens,Fuhuangma 3 and Funong 5 were used as research materials to determine the pathogenicity.According to the size of the lesion,the pathogenicity of 11 strains of anthracnose can be divided into three types: strong,medium and weak.Among them,the pathogenicity of the strain GX19 was strongest,the lesion size of Fuhuangma 3 and Funong 5 was 11.70±2.79 mm and 16.40±5.82 mm respectively in Fuzhou,and the size of lesion was 13.00±1.56 mm and13.40±2.32 mm respectively in Sanming.However,the lesion size of Fuhuangma 3 and Funong 5 by the strain CS3 was weak at the two regions.There sults showed that the pathogenicity between Colletotrichum gloeosporioides and Colletotrichum dematium was also different.The pathogenicity of Colletotrichum dematium was probably weaker than that of Colletotrichum gloeosporioides.3.Three hundred jute germplasms were identified by GX19.It can be divided into six types: high resistance,resistance,middle resistance,middle sensitivity,sensitivity and high sensitivity.Among them,40 germplasms,such as Aidianyeshengzhong,Bama72-1 and Guangbaai,showed high resistance,accounting for 13.33% of the total.On the basis of the statistics of agronomic characters of 300 jute germplasm resources in 2016-2018,combined with the further identification of agronomic characters in 2019 and the screening of resistant germplasm,we constructed the applied core germplasm including resistance to anthracnose.The applied core germplasm includes high fiber yield,elite fiber quality,resistance to stress,suitable growth period and mechanization.With the adding of 4 elite parents,16 applied groups can be divided according to the elite characteristics.After removing the same germplasm from different applied groups,a total of 58 varieties were enrolled in the applied core germplasm of jute,which can promote jute genetic breeding and mine excellent genes.4.In order to facilitate the identification,protection and intelligent management of jute applied core germplasm,the polymorphism of 12 pairs of fluorescent core primers was analyzed by SSR fluorescence labeled capillary electrophoresis,and 140 polymorphic loci were detected.The molecular weight data obtained by capillary electrophoresis were encoded in the form of numbers and English letters.And 12 pairs of fluorescent core primers were selected to construct 58 DNA molecular identity cards in the form of strings,bar codes and two-dimensional codes.The above results will provide the scientific basis of promoting the efficient utilization and rapid molecular identification of jute germplasm resources.