Study On Diversity Of Quality Traits In Tomato Germplasm Resources

Tomato is one of the most important vegetables in the world. In the view of its development trend, not only a bigger amount , but higher quality, high nutritions,nice flavor and commodity characters are also demanded. So, more attentions have been paid to improving the quality chatacters of tomato in recent years. In order to clarify and evaluate the quality characteristics and make the basis for the utilization of germplasm resources in tomato quality improvement,17 quality traits including commodity characters,flavor characters and nutrition characters of 30 tomato germplasm materials were measured and analyzed by morphological markers and molecular markers in this study. The main results were as follows:1. The diversity analysis on 17 quality traits of the 30 materials showed that there were different extend of diversity among different materials and traits, all the coefficient variations were beyond 15%,the average coefficient variation of the tested traits was 32.83%,lycopene content had the largest coefficient variation of 95.42%, soluble solids content had the smallest of 17.43%. The tomato germplasm with better comprehensive quality had been selected, namely TTI1406A,HV-082,HV-028, D550, TTI1110B, TTI1109B, TTI1409A and Ensalada.2. The correlation analysis on the traits showed that there were very significant positive correlations between 12 pairs traits, such as thickness of flesh and longitudinal diameter of fruit, lycopene content and total acidity, weight per fruit and number of locules; very significant negative correlations between 8 pairs traits, such as soluble solids content and transverse diameter of fruit, number of locules and fruit shape index; significant positive correlations between 8 pairs traits, such as weight per fruit and availability of fruit shoulder, lycopene content and soluble solids content; significant negative correlations between 5 pairs traits, such as lycopene content and sugar-acid ratio, color of fruit and fruit shape index. Lycopene content was significant positively correlated with soluble solids content, total acidity and number of locules, negatively correlated with thickness of flesh and fruit firmness;Vc content was significant positively correlated with fruit carpopodial depression size, availability of fruit shoulder, number of locules, weight per fruit and fruit shape index.3. With principal component analysis, 17 principal components were summarized into six principal components which cumulative contributive rate accounted for 80.99%. The six principal components were fruit shape factor, fruit firmness factor, flavor factor, nutrition factor, commodity factor and appearance factor. 4., 30 cultivars were classified into six categories by cluster analysis as the genetic distance was 7.37. The main features of group I: flat round fruit, no fruit shoulder, short stalk, high acidity; groupII: low acidity, high sugar-acid ratio, flat round fruit, low lycopene content ; groupIII: big shape, multiple number of locules, high soluble solids content, high content of lycopene, high VC content, low sugar-acid ratio, this group had good quality traits; groupIV: long-shaped fruit, thickness flesh, high firmness less number of locules, low VC content ; group V: scarlet fruit, small fruit shape, light weight per fruit, less number of locules, high soluble solids content, long stalk, low acidity; groupⅥjust contained a wild-type tomato, which has small and red fruit, high content of soluble solids, high lycopene content, high soluble sugar content and low fruit firmness.5. The RAPD amplification system (20μL) optimized by orthogonal experiment, including the amount of Mg2 +, dNTP and primer was as follows: template DNA (50 ng?μL-1) 1μL, Taq enzyme 0.2U, 10×PCR Buffer 2μL, Mg2 + (25mM) 1.6μL, dNTPs 1.6μL, primer 0.8μL.6. 9 random primers with high polymorphic, clear and stable bands were selected from 150 random primers. There were 44 polymorphic bands in total 66 produced bands, the polymorphic rate was 66.7%, each primer produced 2 to 9 polymorphic bands. Genetic similarity coefficients (GS) between materials were calculated using NTSYS-pc2.1 statistical analysis software,the range of which was 0.56～0.92. Among the test materials, TTI1110B and TTI1409A had a minimum similarity coefficient was 0.56, TTD103A and Yiyin-3 had a maximum one was 0.92. All the 30 tomato materials were divided into four groups by UPGMA method as coefficient = 0.74.7. Most of the materials could be distinguished by morphological marker and molecular marker clustering . The materials classified into the same categories with the two methods included: Ensalada and Huangguo;HV-082-1 and HV-028-2;TTD103A,Lvguo and TTI1406A-1; Yiyin-3 and TTI1108B-1-1-1-1;Zhongyin-1 and Zhongyin-2; TTI1109B-2-2 and TTI1409A-2; Costoluto Genovese, Mortgage Lifter, Rutgers, Xinyin-1, Xinyin-2, Xinyin-3, Guangyin-1, TTI1114A-1, Xihong and TTI1117A-2-2-1.