Identification Of Cherry Tomato Yellow Leaf Curl Virus Disease And Study On Fruit Nutritional Characteristics

Cherry tomato?Lycopersivonesculentum Mill.?has high nutritional value and health function,and plays an important role in human diet.In recent years,with the cherry tomato expanding production and the commercialization of germplasm resources,pests and diseases have spread rapidly,which has become the main factor affecting the yield and quality of cherry tomato.Tomato yellow leaf curl virusdisease?TYLCVD?had become one of the most important diseases causing devastating damage to cherry tomatoes because its large host range and difficult to control.At present,it is mainly prevented and controlled TYLCVD by isolation and chemical reagents,but the effect is not obvious and pesticides cause serious pollution to the environment.However,breeding new varieties of anti-TY can enhance their own disease resistance and increase the yield and quality of cherry tomatoes,which has important significance and practical application value for the development of cherry tomato industry.Therefore,in this study,self-raised 7 parental and 6 F₁ generation cherry tomato materials were used as materials to apply physiological,biochemical and molecular biological research methods,From three aspects to explore the genetic characteristics of tomato yellow leaf curl virus,including detecting the relation genes of yellow curl Virus?Ty-1,Ty-2,Ty-3?and comparing the expression of genes,analysing the defense enzyme activity and gene expression,studingthe nutritive characteristics and hereditary tendency of fruits,in this way we could screen and breed of materials resistant to yellow leaf curl virus and superior quality.Results are as follows:?1?7264 and 5718 of the F1 generation materials of cherry tomato had stronger anti-TY ability,and 855 and 811 as parents can become the superior parent material in the breeding process of cherry tomato anti-TY new varieties.Among them,F1 generation cherry tomato materials 7264,7263,7261,5718 and 5719 contained the disease-resistant hybrid material Ty-3/ty-3,in which 7264 and 5718 genes were significantly higher in expression,and the field showed resistance to disease,7264 has a high heritability,reaching more than 100%,with obvious hybridization advantage,but the 6744 gene expression level is relatively low,only containing the susceptible homozygous material ty-3/ty-3,the disease resistance may be weak.855 and 811 as the parent,the expression levels of the anti-TY gene were significantly higher in the parents and offspring respectively,and the Ty-3/ty-3 genotype of parent can be passed on to the offspring,and the field showed resistance to disease.However,the Ty-1 and Ty-2 genes only contain the recessive homozygous materials ty-1/ty-1 and ty-2/ty-2 in the parental and F1generation tomato materials.?2?The defense enzyme activity of cherry tomato seedlings and its heritability in hybrid breeding were significantly different?P<0.05?.The activities of defense enzymes?PAL,PPO,CAT,SOD,POD and APX?in the leaves of cherry tomato F1 generation material 7264 were more higher significantly,It has a high heritability and a super-high parental plant,while J5 and811 have obvious advantages as parents.The total phenolic,PAL,CAT and SOD activities,as well as the expression levels of both POD and APX genes,have a high heritability,and generally reach more than 90%.The genetic effects on the offspring are obviously,while the PPO and POD activities and the expression level of the CAT enzyme gene was not significant.?3?The quality of F1 generation cherry tomato 7261 and 7264 fruits was the best.Among them,the nutritional quality and secondary metabolites of total phenols and flavonoids were significantly higher,and the average yield was 6 kg/m².Soluble protein,VC content,total phenol and flavonoids have high heritability,reaching more than 100%,and the genetic effects on offspring are obvious.Among them,the genetic effects of 7261 indicators are obvious,and there are super-high parent plants,which have certain hybridization advantages,while the genetic effects of single fruit quality,lycopene,soluble sugar and titratable acid content are not obvious.Comprehensive anti-TY ability and quality,The F₁ generation materials 7264 was screened out strongest anti-TY ability and better quality.Parents J5 and 811 have obvious hybridization advantages,which can be used as the main object of attention for breeding excellent cherry tomato materials.