1. spike shape: the most important morphological feature of string tomatoes is spike shape. There are two kinds of tomato ears: straight fishbone shape and bunch grape shape. Clusters of tomatoes are straight fish bones, and the fruits are regularly arranged in clusters, which are beautiful in shape. The straight fishbone-shaped ear can show all the fruits planted on it, and the connection between the fruits and the ear is clear at a glance.
The factors affecting the ear shape include: ① heredity, different ear structures of different varieties are different. The inheritance of varieties is the basic factor affecting the ear shape. Some varieties are easy to form fishbone spikes, while others are easier to form grape spikes. (2) Cultivation conditions mainly affect the arrangement of fruits on the ear by affecting the length of fruit stalks and the size of fruits. Plants with strong vitality generally have longer pedicels. The shorter the stalk, the easier it is for the bottom of the fruit to bend upwards, and the easier it is for the fruits to overlap each other. At the same time, the bigger the fruit, the easier it is to overlap each other. The overlapping and squeezing of fruits on the ear will cause irregular arrangement. The inconsistency of fruit size on the ear is also an important factor affecting fruit arrangement.
2. Sepals quality and storage period of ear: Good sepals quality and long storage period of ear are important characteristics of string tomatoes. For tomato varieties harvested in clusters, the fruit must stay on the ear longer than that harvested by a single fruit. After the fruit is harvested, the ear must be able to endure a certain degree of post-harvest treatment and keep fresh shape. The reason why tomato varieties harvested with single fruit are not suitable for tandem harvest is mainly because the sepals are thin, easy to dehydrate and dry, and the fruit is easy to fall off from the ear. Even if the fruit can stay on the ear, the ear is not fresh from the top because the sepals are dry and yellow.
Compared with common tomato varieties, it is well known that after the fruit turns red, it stays on the ear for a long time without cracking, and the shelf life of most tomato varieties is longer than that of common tomatoes.
3. Fruit color: The fruits of tomato varieties with long shelf life are mostly orange or red. Generally speaking, the darker the fruit color of fresh red tomatoes, the more shiny it is, and the more popular it is with consumers.
4. Fruit quality: The outstanding advantage of tomato varieties is good product quality (appearance quality). In addition, excellent nutritional quality (rich in minerals, amino acids and vitamins) and flavor quality (moderate sweet and sour, good flavor) are also necessary. At present, most tomato varieties commonly used in China have large fruit shape, soft pulp, low soluble solids content and low lycopene content.