Tomato Quality Traits Diversity Analysis And Agronomic Characters Identification

Tomato is a self-pollinated crop.Tomato breeding has been devoted to breed varieties with high yield,disease resistance and storage tolerance for a long time,which caused the narrowing of tomato genetic base.At the same time,the blind pursuit of yield,resistance and so on inadvertently gave up some genes regulating flavor and nutrition,resulting in poor taste of most commercial tomato varieties,which is difficult to meet the needs of consumers.In this study,based on the analysis of the diversity of tomato quality traits,agronomic characters identification and new varieties comparison were carried out to provide basis for tomato quality improvement and new varieties selection.The main results are as follows.1.Genetic diversity of tomato quality traits.Genetic diversity analysis was carried out by 22 traits of different types of 181 tomato materials.The result showed that the nutrition quality had the highest genetic diversity index(1.38)among nutrition,sensory and commodity quality traits.In nutrition quality traits,lycopene content had the highest coefficient of variation 46.36%,followed by Vc content at 33.71%,and soluble solid content was the lowest at 15.66%.The genetic diversity index of sensory quality was in the middle(0.88).The variation coefficients of hardness,number of locules and total sugar content ranged from 21%to 26%,while total acid content,sugar acid ratio and flesh thickness were between 12% and16%.The commodity quality had the lowest genetic diversity index(0.61).The variation coefficients of size of cordy area around pedicel scar was 16.41%,while that of fruit shape index was 7.44%.2.Correlation of tomato quality traits.The result of correlation analysis showed that in sensory quality traits total sugar content was very significantly positively correlated with total acid content and sugar acid ratio,total acid content was very significantly negatively correlated with fruit hardness,flesh thickness was very significantly negatively correlated with total acid content and number of locules.In commodity quality traits,the size of cordy area around pedicel scar was very significantly positively correlated with fruit ribbing and fruit apex,fruit shape index was very significantly negatively correlated with color of mature fruit and the size of cordy area around pedicel scar.There was also a correlation between different types of quality traits,for instance total sugar content was very significantly positively correlated with soluble solids content,the same correlation existed between fruit shape index and total acid content,between fruit hardness and size of cordy area around pedicel scar,also between hardness and sepal shape.Vc content was very significantly negatively correlated with fruit shape index.And,total sugar content was significantly negatively correlated with lycopene content,soluble solids content was significantly negatively correlated with fruit hardness and flesh thickness.3.Cluster analysis of tomato quality traits.Cluster analysis was carried out based on the nutrition,sensory and commodity quality traits of tomato,classifying 181 tomato materials into 6,5 and 6 categories,respectively.Based on the quality characteristics of tomato,the ordinary berry-red and berry-pink tomato materials were analyzed by cluster analysis.The ordinary berry-red material was divided into 5 categories,and the pink,6 categories.Cluster analysis was conducted on ordinary small-fruit-type,medium-fruit-type and large-fruit-type tomato materials,and each got 3 categories.4.Identification and evaluation of tomato agronomic characters.Focusing on the main criteria of high nutritive value,good commodity nature,high yield and disease resistance,181 tomato materials were identified and evaluated.Materials with good overall performance were selected,including 8 ordinary berry-red tomato materials(P1,P8,P19,P23,P25,P31,P43,P45)and 7 ordinary berry-pink tomato materials(P90,P94,P97,P99,P120,P121,P124).5.Comparison of new tomato varieties.Focusing on the main criteria of high yield,good quality and disease resistance,14 tomato varieties from 7 breeding units in China were compared.Varieties with good overall performance were selected,including F02(‘Dongnong729’)、F06(‘Zhongza 1721’)、H1(‘Jingfan 502’)、Y3(‘Hongchuanzhu’)and Y4(‘ST18-1’).The results provided data and basis for tomato variety selection.