CHAPTER ONE
INTRODUCTION
Introduction
1.1 Background of the study
Tomato (Solanum lycopersicon L.) is one of the most widely
and important cultivated crop in Africa (Opena, et. al., 1990). Tomato is the
world’s largest vegetable crop after Potato and sweet potato, but it tops the
list chart of canned vegetables. In Nigeria Tomato is recorded as the important
vegetable after Onion and paper (Fawusi, 1987). It is an important condiment in
most diet and a few cheap source of vitamin, with a large quantity of water
(%), calcium (%), and Niacin all of great important in the metabolic process of
man.
Tomato can be grown in a variety of geographical zones in
open filed or in greenhouses (screen house), and the fruit can be harvested
manually or by mechanical means. In 2014, the global area cultivated with tomatoes
was 5 million hectares with a population of 171 millions tones. The major
tomato producing Countries are; China and India. (FAODSTATE, 2017). Under
certain conduction such as pruning, weeding, irrigation, frost free
environment, etc, the crop can be perennial or semi-perennial, but for
commercial purpose. It is considered as annual (Geisenberg and Steward, 1986).
Although there are many types of growing system for
greenhouse tomatoes, the two principle cropping systems are: “Two crops per
year and one crop per year”, its significance doesn’t lie only on profit, but
also in the income generated in the local economy for farmers and agricultural
workers (Guldinez, 2013). There are several categories of protected vegetable
production methods which provide some degree of control over various
environmental factors such as: greenhouse, tunnels and covered field
(Nieves-Garcia et. al., 2011). Although there is no quantitative record about
the world’s vegetable production in greenhouse, some calculation have been
made. For example, in 2012, the greenhouse vegetable production was about 81
million kilo-gram (kg), of which 40 million kg of the total production was
tomato, and 37 million kg was cucumber. More so, In 2012, the tomato production
in Northern America Accounting for about 52% of the market in Canada and 22% of
the market in the United State (form credit Canada, 2012). But tomato
production in Nigeria is low as compared to those of temperate zones due to
differences in cropping environment conditions, lack of high yielding
varieties, and cultural practices applied to the crops in the field.
Commercially, tomato fruit can vary in colour, size and
shape (Vaughan and Heissler, 1997). The fruit contains large quantity of water,
vitamin minerals such as hycopene (which gives the fruit it’s predominantly red
colour) and beta-carotene (which contains up to 3% sugar of the fresh fruit
weight). Tomato also contains tomatine and alcocide with fungicide properties.
Tomatine concentration decreases as the fruit matures which helps to determine
the taxonomy of the species. Therefore, if can be useful (OECD, et. al., 2018).
Tomato is one of the best studied cultivated dycotyledon
plant of the molecular level and has been used as a model species for research
into gene mapping, characterization (example pathogenic resistance gene) and
gene transferred approaches. It is also useful to study other plant trait such
as fruit ripening, hormonal function and vitamin by synthesis (Chetelat, et.
al., 2006).
1.4 Origin and distribution of tomato
The edible tomato, often red berry of the plant solanum
esculentum is a species originated from Western South America and Central
America. Its domestication and uses as a cultivated food may have it indigenous
to the Mexicans. From there, it was brought to Europe and to other part of the
European-colonized world during the 16th century. Although there is no much
history on how tomato was spread eventually introduced to Africa in the early
19th century and finally to Nigeria.
Tomato has been cultivated since prehistoric times with the
earliest agricultural techniques and its cultivation and production keeps
improving and evolving. This depends on several factors such as organoloptic
properties of the fruits, farming system, agronomic practices etc. Modern age
of commercially grown tomato started with the effort of Alexander W.
Livingston. In 2009, worldwide tomato production rose to 158.3 million tons,
surpassing the previous years by 3.7%. The largest producers were China with
24% of world production, followed by United States, Turkey, India, Egypt and
Italy.
1.3 Health Benefits of Tomatoes
Tomatoes are a great source of vitamins
A single tomato can provide about 40% of the daily
recommended minimum of vitamin C. What’s more, tomatoes supply vitamin A, which
supports immunity, vision, and skin health; vitamin K, which is good for your
bones; and potassium, a key nutrient for heart function, muscle contractions,
and maintaining a healthy blood pressure and fluid balance.