Tomatoes belong to the Solanaceae (the nightshade family) along with potatoes, peppers and eggplants. Lycopersicon esculentum is a perennial plant in the tropics but in northern climates it is grown as an annual. Botanically this vegetable is a fruit (a berry). Flowers are generally borne in clusters of 4 to 8 but small fruited types may have 30 to 50 flowers per cluster. The flowers are mainly self pollinated by the wind. The fruit has 2 to 18 locules (chambers or sections).
Tomato is one of the most important vegetable crops in the world. The tomato belongs to the family Solanaceae, genus Lycopersicon, which is a relatively small genus within the large and diverse family consisting of approximately 90 genera.
Lycopersicon species are native to Ecuador, Peru, and the Galapagon Island though most evidence suggests that the site of domestication was Mexico (Taylor, 1986).
The tomato is a native of the Peru, Bolivia, and Ecuador area of the Andes Mountains. Its antiquity is uncertain in regard to cultivation but it was being cultivated when America was discovered by Europeans. It was not until 1835 that the tomato was considered suitable as a food crop in the northeastern United States.
Tomatoes play a vital role in human diet and are a good source of vitamins and minerals (Thompson, 1949; South Pacific Commission, 1992). In Nigeria, tomatoes are grown during both the wet and dry seasons but they attract higher profits during the dry season when the demand is higher than supply. Tomato is an excellent source of vitamins, minerals, and antioxidants which help control cancer, health disease as well as improve the general health of man (Antonio et al., 2004). Tomato (Lycopersicon esculentum Mill.) is one of the most important vegetables grown for their edible fruits. Tomato is cultivated in Nigeria with an annual production of six million tonnes (Idah et al., 2007).
Tomato (Lycopersicon esculentum Mill.) constitutes one of the most valuable horticultural crops, not only because of its economic importance, but also for its sensory qualities and nutritional value. It is consumed in the form of fresh as well as processed products. More than 80% of tomatoes grown throughout the world are processed into products such as sauce, juice, ketchup, canned tomato, stew and soup (Viskelis et al., 2015).
High consumption of fruits and vegetables is generally considered to be beneficial to health. Based on abundant literature, the potential public health importance of increased consumption of fruits and vegetables has been widely recognized, both for cancer 1–3 and CVD 4Routine or habitual consumption of fruits and vegetables has been strongly associated with reduced risk for many of the common cancers (Steinmetz and Potter, 1991).
Fruits and vegetables differ widely in physical structure and phytochemical content. In recognition of this, the Dietary Guidelines for Americans recommend consumption of a variety of fruits and vegetables that differ in nutrient content (eg, bright-orange vegetables like carrots, sweet potatoes, and pumpkin are good sources of carotenoids).
The guidelines also state that fruits and vegetables can be consumed in any form (fresh, frozen, canned, dried, or juice), although it is noted that fruit juices generally do not contribute to dietary fiber intake. Other schema for categorizing the variety of fruits and vegetables are also used in nutrition surveillance and nutritional epidemiologic studies
Tomatoes respond well to high temperatures. The minimum temperature for seed germination is 10 C with a maximum temperature of 35 C and an optimum range of 17 to 20 C. Most field transplants should not be set out until the danger of frost is past. An optimum growth rate is obtained at 22 C with reductions occurring above 30 C and below 12 C. Fruit setting is inhibited above 30C and below 16 C. Rough fruit (cat faced) results from growing temperatures below 16C. Root growth does not occur below 16 C. Tomatoes require adequate, even moisture, particularly at flowering and during fruit set. Tomatoes grow best in well drained soils that are well supplied with organic matter. Sandy soils are suited for early production, loam and clay loam soils are suited for later production. Shelter from wind is important especially for early production. This crop also benefits from the use of plastics such as ground mulches, row covers, and tunnel houses.
Tomato requires nutrients such as N, P, K, Mg, Ca, Na and S for good production. These nutrients are specific in function and must be supplied to the plant at the right time and in the right quantity (Shukla and Naik, 1993).
Most soils in Africa are poor compared with other parts of the world (Bationo et al, 2006). African soil nutrient balances are often negative due to a low level of fertilizer inputs, and soil nutrient depletion is a major reason for decreasing or stagnation of agricultural productivity (Sanchez, 1997. Mbah 2006) asserts that soil fertility is a major overriding constraint that affects all aspects of crop production. As is the case in other regions in Africa, local farmers use inadequate nutrient inputs, inappropriate quality and inefficient combinations of fertilizers, which in the end prove to be very costly (Palm, 1997). A consequence of this trend is a deeply unbalanced soil nutrient composition that ultimately leads to a reduction in crop yield potential (Tonfack et al., 2009). Nutrients, when in adequate quantity, increases fruit quality, fruit size, colour, and fruit taste of tomato (Azad, 2000). It also helps in increasing desirable acidic flavor
The use of organic manure, e.g. poultry dropping and ruminant dung has improved agricultural productivity in West African countries. Organic manure helps to improve the physical condition of soil and provides the required plant nutrients. Organic manure also enhances cation exchange capacity and acts as a buffering agent against undesirable soil pH fluctuations (Jones and Wild, 1975; Ngeze, 1998)
The use of organic manure alone is faced with problems of bulkiness and dirt. A balanced use of organic and inorganic fertilizers could enhance soil chemical, physical, and biological properties as well as rate of nutrient turn over within the soil-plant system (Paul and Mannan, 2006). Combined use of organic and Inorganic fertilizer reduced cost and amount of fertilizer required by crops (Krupnik et al., 2004). It also produced highest plant growth (Alam, 2006). In vegetable production, organic fertilizer combined with inorganic has proved to be effective in combating nematodes