Tomato is a savory, bright red and edible fruit scientifically known as Lycopersicon esculentum. It is native to South America and is now cultivated all over the world with many varieties often grown in green houses in cool climates. The fruit is consumed in a wide variety of ways like eaten raw, in many delicacies as well as in drinks. Botanically it is considered as a fruit but it is a vegetable in general terms used for culinary purposes. The fruit is rich in lycopene which has many efficient health effects. Tomato is a member of the nightshade family attaining a height of 1-3 m with a weak stem that sprawls over ground or sometimes twines over other plants. Although it is a perennial plant but also grown as annual plant in the temperate climates.
The plant is grown all over the world with thousands of known cultivars adapted to different climatic conditions. Commonly cultivated varieties include tomberries, beefsteak tomato, cherry tomato and plum tomato. They are one of the most important garden plants in United States. China is the largest producer of tomatoes followed by United States and Turkey. About 130 million tonnes of tomatoes were produced in 2008 in the whole world. California accounts for 90% production of the plum tomatoes which comprises 35% of the total world production of tomatoes. They may be classified as determinate and indeterminate. Determinate type bears all fruits at once after attaining a certain height. They are generally used for commercial production and are canned. Indeterminate types grow in the form of tender vines that produce fruits continuously unless and until destroyed by frost. An intermediate form between the two is also known that produces a second crop even after the production of the initial crop.
Tomatoes grow well with a sunlight of 7 hours a day. The NPK fertilizers are required in the proportion of 5-10-10 although manure and compost are also required. Cultivated varieties differ in their degree of resistance to diseases. They are susceptible to the attack of fungi, nematodes, stink bugs, cutworms, tomato hornworms and tobacco hornworms, aphids, cabbage loopers, whiteflies, tomato fruitworms, flea beetles, red spider mite, slugs and Colorado potato beetles. When insects attack tomato plant, the plant produces plant peptide hormone, systemin which releases protease inhibitors responsible for slowing down the growth of insects. The stamens remain closed inside the corolla. The wild varieties require cross pollination. The varieties cultivated in green houses are self pollinated. Generally unripe tomatoes are picked up from the farms and then sprayed with ethylene gas to become ripe. Unripe tomatoes are firm. After ripening they attain bright red colour and are somewhat soft in touch. Ethylene is a hydrocarbon produced by plants which acts as a cue to support ripening process. Genetically modified varieties are also marketed with the trade name Flavr Savr.
Tomato contains a compound known as lycopene which is potent antioxidant helpful in preventing the risk of prostate cancer. It also protects the skin from the effect of harmful UV rays. Tomato is also a rich source of vitamin A and C. when unripe they can be stored at room temperature and uncovered until they ripen. When ripe they can be kept in refrigerator. Like other members of the nightshade family the leaves and stems of these plants contain atropine and other tropane alkaloids which can be toxic if ingested. Fruit lacks these compounds. Leaves, stems and unripe fruit contain another potent compound tomatine which is poisonous. The plant may be toxic to dogs if they consume it in large amounts. The plants are dicots with compound leaves often called as regular leaf (RL) plants. Leaves are 10-25 cm long, odd pinnate with 5-9 leaflets on petioles with a serrated margin. Both leaves and stem are hairy. The flowers appear at the apical meristem. The anthers have fused edges forming a column around the pistil’s style. The flowers are 1-2 centimetres across, yellow, with five pointed lobes on the corolla; they are borne in a cyme of 3-12 together. Seeds come out from the fruit and can be dried or fermented before germination.