Comprehensive Evaluation And Genetic Trend Analysis Of Skin Texture Of 50 Watermelon Germplasm Resources

This study used 50 watermelon germplasm resources as experimental materials to systematically identify and evaluate the fruit cortex of watermelon.In addition,watermelon varieties were selected as parents and hybrid combinations were prepared.10 groups of F1generation and parents were selected for genetic trend analysis of fruit cortex texture.The research results will provide a theoretical basis for the systematic evaluation of watermelon peel texture,the determination of the genetic law of watermelon peel texture traits,and the rational selection of cultivar and breeding parents.The main results are as follows:1.Thirteen peel traits of 50 watermelon germplasm materials were measured,including eight TPA texture analyzer traits（hardness,brittleness,chewiness,adhesiveness,cohesion,resilience,adhesiveness,elasticity）,peel color,texture color,texture shape,peel cell lignin content and stone cell content.The variation range of its genetic coefficient of variation is 7.48%to 63.33%.The trait with the lowest coefficient of variation is elasticity,while the trait with the highest coefficient of variation is skin color.This indicates that there is rich diversity and difference in watermelon peel traits.2.There is a correlation between fruit peel traits,with a correlation coefficient of as high as0.99 between hardness and brittleness,and a correlation coefficient of as high as 0.81 between hardness and adhesiveness,all showing extremely significant positive correlations.The correlation coefficient between lignin and stone cell content is as high as 0.85,indicating a highly significant positive correlation.3.Principal component analysis was conducted on the peel traits,lignin and stone cell contents of 50 germplasm resources,as well as texture indicators.A total of 6 principal components were extracted.Principal component 1 includes hardness,brittleness,chewiness,adhesiveness,and resilience,mainly reflecting the texture characteristics of watermelon peel;Principal component 2 includes lignin,stone cells,and peel thickness,which collectively reflect the structure of watermelon peel;Principal component 3 includes information on single fruit weight and stripe shape,reflecting the phenotypic traits of watermelon peel;Principal component 4includes cohesion and pericarp thickness,reflecting the cohesion of pericarp;Principal component5 includes elasticity indicators,which centrally reflect the elasticity of the fruit peel;Principal component 6 includes the skin color,reflecting the information of the skin color.4.The F₁generation was evaluated for genetic trends using indicators such as ultra-high parental rate,ultra-low parental rate,genetic transmissibility rate,and dominance ratio.The results showed that the lignin content,stone cell content,and texture elasticity indicators of the fruit peel cells had strong hybrid advantages,showing a genetic trend towards higher parents.The peel adhesiveness,adhesiveness and chewiness have relatively weak heritability,showing a genetic trend towards lower parents.The fruit peel hardness mostly exhibits a negative ultra low parent advantage in various F₁offspring combinations,indicating that the inheritance of fruit peel hardness tends to develop in the direction of ultra low parents.