Study On Sepal Traits And Diversity In Tomato

Tomato (Solanum lycopersicum L.) is one of the important vegetable crops. Tomatodemand is increasing in our daily life. Improvement of fruit quality traits is the major task fortomato breeders. As important components of fruit quality, commercial traits also need to betaken into account in order to select fruits which will meet consumer’ s requirements. A totalof68tomato accessions were used to study the development process of sepal and sepalshape,correlation among sepal traits, and the correlation between sepal traits and fruitcharacters. Which will build the foundation for describe and further study on sepal traits.Themain results were as follows:1.Gradual changes of sepal shape were observed from flowering time to fruit maturitystage，angle between sepal and longitudinal axis of flower varied from less than90degrees toover180degrees.There were different types of sepal shape at fruit red ripe stage，which wasthe main study object in this paper.2.Sepal shapes and classify rule: It can be classified into four types. The following is theangle between stretching direction of sepal and the fruit vertical axis．Spread is in the range of90-100degrees，up-spread is101-170degrees，upright is171-180degrees，scroll means theangle is more than180degrees，and it is entad curling．3.Diversity analysis of8sepal traits in68tested accessions showed that: sepallength,width,thickness,surface area,ratio of length to width and relative length were rangedfrom8.24to35.71mm,1.34to7.98mm,0.23to2.77mm,5.53to106.48mm2,3.03~13.44and0.23~0.90,respectively. In40common tomato materials,sepal length,width,thickness,surfacearea,ratio of length to width and relative length were ranged from16.60to35.71mm,2.37to7.98mm,0.90to2.77mm,37.43~106.48mm2,3.03~13.44and0.23~0.74respectively. Largerange of variation coefficient was found for the ratio of sepal length to width，Higher variationcoefficient was found for sepal ratio of length to width. In28cherry tomato materials, Sepallength,width,thickness,surface area,ratio of length to width and relative length were rangedfrom8.24to25.23mm,1.34to4.98mm,0.23to1.41mm,5.53~62.87mm2,3.33~7.58and 0.32~0.90respectively. Large range of variation coefficient was found for sepal surface area，lower variation was found for sepal number. Scroll was the main type in the accessions.4.Correlation analysis among sepal traits showed that there were very significant positivecorrelations between sepal length and ratio of length to width, between sepal surface area andrelative length, between sepal width and sepal thickness,between sepal thickness and sepalsurface area;there were very significant negative correlation between sepal width and sepalratio of length to width, between sepal thickness and sepal shape in common tomato. Verysignificant positive correlation between sepal length and sepal width,thickness,surface areaand relative length,between sepal width and sepal thickness and surface area,between sepalsurface area and sepal thickness and relative length, between ratio of length to width and sepalrelative length;very significant negative correlation between sepal width and sepal ratio oflength to width in cherry tomato.5. Correlation analysis between the sepal traits and fruit characters in common tomatoshowed that there were significant positive correlation between sepal length and soluble solidscontent,fruit longitudinal diameter,lycopene content and pedicel length,between soluble solidscontent and sepal ratio of length to width.Very significant negative correlation betweensoluble solids content and sepal width,between sepal shape and fruit firmness.Correlation between the sepal traits and fruit characters in cherry tomato showed that therewere very significant positive correlation between sepal length,width,thickness and surfacearea and fruit weight, fruit longitudinal diameter, fruit transverse diameter and pedicellength,between fruit flesh thickness and sepal length,width and surface area, between sepallength and fruit firmness,between sepal width and fruit carpopodial depression size,betweensepal relative length and fruit shape index.Very significant negative correlation betweensoluble solids content and sepal width and surface area.6. Cluster analysis of sepal traits at fruit red ripe stage:The40common tomatoaccessions were classified into four categories.Genetic distance was estimated as10.02.Theorder of sepal length,width,thickness,surface area,ratio of length to width and relative lengthamong four categories was Ⅰ＜Ⅱ＜Ⅲ＜Ⅳ.Comprehensive analysis showed that the fourthgroup was the best in sepal traits and fruit characters.The28cherry tomato accessions wereclassified into four categories.Genetic distance was estimated as12.52.The order of sepallength,width,thickness and surface area among four categories was Ⅰ＜Ⅱ＜Ⅲ＜Ⅳ.The order of sepal ratio of length to width and relative length were Ⅲ＜Ⅳ＜Ⅰ＜Ⅱ,Ⅰ＜Ⅲ＜Ⅱ＜Ⅳ respectively.Comprehensive analysis showed that the fourth group was the best in sepaltraits and fruit characters,the main features were largest in sepal length,width,andthickness,better fruit shape index (0.93) and higher soluble solids content (7.1%).