DETERMINATION OF THE VARIABILITY TRAIT EXISTING BETWEEN THE EXOTIC AND LOCAL CULTIVARS OF TOMATO

CHAPTER ONE

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”, it’s 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 dicotyledon 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).

1.2 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 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. 
They protect heart health
Tomatoes contain an antioxidant called lycopene, which is responsible for their red color. Research suggests that in terms of heart health benefits, it’s more effective to eat tomatoes and tomato products than take lycopene supplements. Other studies have shown that higher blood levels of lycopene are tied to lower death rates for people with metabolic syndrome, a cluster of risk factors that raise the chances of developing heart disease, diabetes, and stroke.
Improve you vision
Lycopene is also good for your eyes. And that’s not the only peeper-protective nutrient in tomatoes; they contain lutein and beta-carotene as well. According to research, those nutrients support vision and protect against eye conditions including cataracts and macular degeneration.

Boost digestive health

The fluid and fiber in tomatoes may be helpful if you’re prone to constipation. (According to the USDA one large tomato contains 6 ounces of fluid, and 1.5 grams of fiber.) Just be aware that in some people, the acidity from cooked tomatoes may trigger or worsen acid reflux and indigestion. 

Help with diabetes management

Tomatoes may be a protective food for people with type 2 diabetes: In one study, people with diabetes who supplemented with cooked tomatoes for 30 days experienced a decrease in lipid peroxidation, a chain reaction in which substances called free radicals attack fat, leading to damage that ups the risk of heart disease. This is particularly important, because diabetes doubles the risk of stroke and heart attack. 
Guard skin health
A 2011 study found that the combination of tomato paste and olive oil protected against sun damage, and boosted the production of pro-collagen, a molecule that gives the skin its structure and keeps it firm and youthful. Scientists believe that the lycopene in tomatoes is key. It’s at its highest concentration when tomatoes have been cooked, and olive oil boosts its absorption from your digestive system into your bloodstream.
Protect against cancer
Observational studies have found links between the superstar compound lycopene and fewer incidences of prostate, ovarian, lung, and stomach cancers.
Tomato is a significant source of Umami flovour. This is consumed in diverse ways; raw or cooked, sources, salad and in drinks.
Tomatoes are also one of the main ingredients in hundreds of dishes and products that are sold in Supermarkets throughout the world.
Tomatoes serve as the best to people who wish to grow fruits and vegetables. It is also an essential part of many recipes as well as many produced products such as “Tomato Ketchup and Tomato Paste”. Tomato is advantageous over other types of crops, such as:

High Yield which result in their high economic value

High nutritional value with high level of Pro-vitamin A and C, as well as being ranked highest in their contribution to human diet.

In competition with other vegetables, tomato is a short duration crop in term of time of production.

They are suitable in diverse cropping system used on grains and legumes.

1.4 Justification of the study
Tomato is one of the most demanding vegetable in Nigeria and Western part of the world. Mexico and India are the major supplier of tomato as far as tomato consumption is concerned. Local production is unable to meet the demand since most of the product is left to rot on farm sites due to poor storage facilities, poor road network linkage to farms and the markets in the rural and urban areas. This prevents purchasers from purchasing it from the farmers as the cost tends to increase due to the state of the roads. The perishable nature of the fruit also forms part of the reasons why local production is not able to meet the market demand.

1.5 Objective of the study
The objectives of the study were to:

Determine the variability trait existing between the exotic and local cultivars of tomato, planted in Obio Akpa.

Assess the number of fruits per plants and fruit yield per hectare.