Tomato is one of the most important vegetables in the world as well as in Turkey. Molecular markers, along with qualitative and quantitative morphological characters, are important markers used to detect genetic variation within plant species . Measurements of morphological traits provide a simple application to assess genetic variation with simultaneous assessment of genotype performance in certain ecological conditions, although these morphological characters are often influenced by environmental factors . Flower, leaf and fruit characters are important distinguishing indicators in determining the variation among tomato genotypes . Characterization studies are carried out in different regions of the world in tomato based on morphological data. Fruit descriptors are more promising markers for morphological differentiation of tomato genotypes [43, 44]. Different researchers have divided tomato genotypes into 4 groups in terms of fruit color (before maturity): greenish-white, light green, green and dark green . In the study by ; tomatoes genotypes were divided into 5 groups (Greenish-white, green, light green, dark green, very dark green and dark) according to the fruit color (before maturity). Fruit skin color is controlled by the Y gene, so it is not affected by environmental conditions. In other words, it does not show genotype × environment interaction. Therefore, fruit color is an important parameter in the differentiation of genotypes [46). In tomato, expression of fruit shape traits is known to have a high degree of genetic determinism. Fruit shape and size is a very important feature both for the consumer and for marketing. Fruit shape is one of the most promising features that can be used for precise identification of tomato genotype . In present study wide variation was observed in fruit shape among the genotypes; round, heart-shaped, flat, slightly flat and cylindrical were recorded. According to the fruit shape;  reported that the genotypes were divided into 6 groups (flattened, slightly flattened, cylindrical, rounded, high-rounded, and heart-shaped), while  reported that they were divided into 4 groups (rounded, flattened, ellipsoid and heart-shaped). It has been determined that there are similarities and differences with other studies in terms of fruit shape. These differences are thought to be due to the genotype difference used in the studies. In this study, variations in fruit color were observed between genotypes. There are 6 different groups in terms of fruit color (yellow, pink, light red, red, dark red and brown). Approximately 66.6% of the genotypes have red fruit color. Flesh color is a parameter used in tomato morphological differentiation. In a similar study; it was stated that tomato genotypes were divided into 5 groups (red, yellow, orange, pink and brownish color) according to fruit flesh color . The fruit flesh colors detected in this study are similar to the findings of other researchers. In this study, genotypes were evaluated in 3 groups according to the fruit firmness parameter as soft, medium and firm. Many factors such as genotype, harvest time, plant nutrition can affect fruit firmness. In a similar study; It was determined that the fruit cross-section shape of the genotypes was round (85.51%), irregular (13.04%) and angular (1.45%) . In this study, they were evaluated in 3 groups according to their cross-sectional shapes. In this study, green shoulder was detected in some genotypes, while it was absent in others. In many similar studies, green shoulder in fruits was expressed as present or absent [37, 45]. Fruit length varied between 68.21(6.821 cm) mm and 17.62 mm (1.762 cm). This result was also very similar to previous studies published by  and . In a study by  reported that fruit length is between 40.7 - 94.6 mm and fruit weight is between 62.6 - 446.6 g. In this study; fruit weight had a positive and significant association with fruit length and fruit diameter. It can be said that there are some similarities with other studies in terms of fruit width and weight. We recorded wide range of fruit weight among the genotypes. The variation of fruit weight could be due to the differences of tomato genotypes used in the studies. There are many studies investigating the SSC (%) content of tomatoes . The results of the research were partially different from other studies. Such differences between tomato genotypes have also been observed by . Principal component analysis has been used by many researchers to assess morphological diversity and establish genetic associations between tomato genotypes [19, 42].
The ISSR technique has been used successfully in many studies to identify genetic variations among tomato genotypes. In genetic diversity study with ISSR markers carried out in the Iran and Turkey tomato genotypes, the average number of bands per marker was 13, the mean number of polymorphic bands was 13.2, and the mean polymorphism rate was 100% . In another study, the average number of polymorphic bands per marker was determined as 4.9 in the SSR analysis performed in the tomato genotypes in Greece. In additon, the rate of polymorphism was reported as 48.9. Researchers determined that genetic similarity values ranged from 0.56 to 0.95 . Similarity index showed a change from 0.01 to 1.87 between genotypes in the RAPD analysis in tomato genotypes . In another study with SSR markers; the genetic similarity value was found to be 0.79 on average . Molecular marker results obtained from the current study are generally in agreement with previous studies. The differences can be explained by the different marker systems used and the variability in genotypes.
As a result, genetic diversity was determined with the help of morphological and molecular markers in 24 tomato genotypes collected from Erzincan province. A wide variation among genotypes emerged based on data from the markers (morphologic and molecular) used. According to ISSR molecular marker data, the most genetically distant genotypes were ≠1 and ≠24. Genotypes with low genetic similarity are extremely important for cross-breeding. In terms of morphological characteristics, especially in terms of fruit length, fruit width, fruit weight and SSC (%), genotype ≠22 produced high results compared to the other genotypes. The data are an important tool for identifying and maintaining the diversity of this germplasm.