CHAPTER ONE
1.0 Introduction
Background of the Study
The genus Telfairia, named after the famous Irish naturalist, botanist and plant collector Charles Telfair, is a nutritionally important but scientifically little known member of the family cucurbitaceae and order Telfaireae (Botanica, 2004). The two main species in the genus are Telfairia occidentalis (Hook (F) and Telfairia pedata (Smith ex sim World Agro Forestry Centre, 2004). In Africa Telfairia occidentalis is commonly referred to as fluted pumpkin or fluted gourd.
According to Ng (1993), common name that have been used for Telfairia occidentalis outside Africa include gourd, queen’s nut, Zanzibar oil vine. Telfairia occidentalis is localized to Africa (Robinson and Walters, 1997).
Organically grown crops are crops that have been cultivated without the use of synthetic agricultural inputs such as synthetic pesticides, herbicides, fungicides, soluble mineral fertilizers, growth regulators, components derived from genetically modified organisms (GMO) and irradiation (USDA, 2002). They are vegetables that use animal manures, green manures, compost manures and a varied crop rotation stead of readily synthetic in fertilizers. Vegetables play a significant role in human nutrition, especially as sources of dietary fiber, minerals, and vitamins (Craig and Beck 1999, Wose et al., 2000). Vegetables remain an important source of nutrients in many parts of the world and offer advantages over dietary supplements because of low cost and wide availability.
Plants of diverse varieties exists, the value of each plant depends on its known use for medicinal, nutritional or aesthetic purposes. Plants used as food depends on their nutritional properties, this is turn is determined by their phytochemical components.
It is widely assumed that method of farming affect the nutritional quality of crops particularly organic farming produce higher quality than inorganic farming method (Mozafar, 2004). Benefits derived from organic farming is due to an absence of synthetic chemical residues in the crops. Although it is scientifically challenging to adequately assess the nutritional quality of crops grown in different cultivation methods, because the final measure of nutritional quality of food lies in the organism that consumes the food and the tropic level of such organism. However, different farming methods have their different reaction pattern that result in the culinary value of that product. Nutritional quality is defined as the value of the food for the individual consumer’s physical health, growth, development, reproduction and psychological and emotional well-being. Lester (2007) reported that organic farming system avoid the severe negative effects on human health that can caused by inorganic method of farming. Interest in organic food has increased worldwide in response to concerns about conventional agricultural practices, food safety, taste, human health, animal welfare and the environment (Baker et al., 2006). Opinion polls have suggested that a significant proportion of organic consumers believe that organic food is qualitatively, contained a higher concentration of nutrients as a result of the superior soil management and activities of soil micro-organisms. A range of positive inferences are made by consumers on organic (Willer et al., 2007). Public concern about nutritional quality of food grown in conventional farming system has intensified in recent years. A series of food scares and the controversy surrounding genetically modified crops have prompted heated debate about the safety and integrity of inorganic food. Against this background, demand for organically grown food has been growing rapidly. However, the study assesses the nutritional quality of fluted pumpkin (Telfairia occidentalis) leaves grown in organic and inorganic methods of farming system
According to Akoroda (1990), Telfairia is indigenous to Nigeria and is widely grown in tropical wet coastal areas of West Africa, principally in Benin, Cameroon, Ghana, Nigeria and Sierra Leone. Telfairia occidentalis is a leafy vegetable crop commonly cultivated in the South Eastern part of Nigeria (Odiaka et al., 2008). In Southern part of Nigeria, the leave of Telfairia occidentalis is cooked in almost all the hotels, restaurants and bars on daily basis. In Akwa Ibom and Cross River State of Nigeria in particular, the vegetable soup is called “Edikan Ikon soup”. Also, in all traditional feasts or parties “Edikan Ikon” soup is one of the main dishes of such occasions. (Ekpo and Udo, 2015.)
However, it is gradually gaining prominence in the South Western part of the country (Schippers, 2002).
This research thesis of telfaira occidentalis (fluted pumpkin) is a deliberate attempt to differentiate between organic and inorganic method of farming as carried out in a geographical area situated on Latitude 4o36’N; Longitude 7o45’E on the tropical rainforest of Akwa Ibom State, south-south Nigeria.(Atlas, 2009).
In Africa indigenous vegetables remain popular in rural areas where they are often considered to be more nutritive than exotic vegetables. Telfairia occidentalis commonly called fluted pumpkin is an important leaf and seed vegetable indigenous to Southern Nigeria and grown in the forest zone of west and central Africa (Nigeria, Ghana and Sierra Leone being the major producers). It probably originated in south east Nigeria and distributed by Igbos who have been cultivated this crop since time immemorial.
Ekpo et al., (2012) reported that food value of fresh vegetables varies from species to species and also from age to age owning to the large amount of mineral nutrients and water present in each species. In the rural areas where the popularly eaten food is mainly carbohydrate, indigenous vegetables play useful role in producing food quality like proteins, minerals, vitamins and fats, also roughage part of the vegetable aids in digestion.
The nutritional value of pumpkin seeds is different from that of leaves. The protein contents of seeds and leaves are 20.5g and 2.9g, respectively. Seeds have high nutritive and calorific values which make it necessary in diets. Fluted pumpkin is of local ethnobotanical importance in the folklore, dietary and cropping systems of Igbos. The level of iron is the factor for use of the leaf extraction as blood tonic which can be administered to weak patient.
Nitrogen is usually ascribed with the building up of leaf tissues. This is one of the essential elements most commonly used to increase crop yield. It is a constituent of all protein and chlorophyll. Plant tissue, usually contains more nitrogen than any other nutrients. Nitrogen application is used to produce rapid vegetative growth of vegetables. It promotes luxuriant growth, and increases number of leaves. These encourage photosynthesis and partitioning of photosynthesis rate into the economic parts of the plant. It is also necessary for reproduction and promotes the uptake of phosphorus and potassium by plants. However, nitrogen requirement for vegetable is 50kg N/ha or more in savannah zone of Nigeria. It has been reported that 100kg N/ha is suitable for vegetable based on dual purposes (leaf+ fruit). The recommended rate for the production of fluted pumpkin is 16okgN/ha (Oyekunle and Oyerele, 2012 ).
Although, many research activities have reported better performance of crops with fertilizer application one of the method through which plants would display its potential genetic capability is by supplying the plants with adequate amount and types of fertilizer at the right time.
Research efforts are therefore required to recommend fertilizer types for sustainable production of Telfairia occidentalis in Ogbomoso, the Guinea Savanna zone of south west Nigeria.
Telfairia occidentalis commonly called fluted pumpkin grows in the forest zone of west and central Africa, most frequently in Benin, Nigeria and Cameroon. It is a popular vegetable all over. It is rare in Uganda and absent in the rest of East Africa. It has been suggested that it originated in south east Nigeria and was distributed by the Igbo’s who have cultivated this crops species since time immemorial. It is however, equally possible that fluted pumpkin was originally wild throughout its range, but that wild plant have been harvested to local extinction and now are replaced by cultivated form.
According to Ajayi et al., (2006), the crop is an endangered species and the genetic diversity is valuable in crop breeding programme, as it helps in the identification of diverse parental combinations to create segregating progenies with maximum genetic variability (Barret and Kidwel, 1998) and facilitate introgression of desirable genes from diverse germplasm into available genetic base (Thompson et al., 1998). Genetically diverse and geographically isolated lines may generate a wide range of variation when brought together (Khantun et al., 2010). Knowledge of genetic diversity among existing cultivars of any crop is essential for the long term success in breeding programme and maximizes the exploration of the germplasm resources (Balaj et al., 2002). This is because it provides knowledge of genetic relationship among breeding population and helps in selecting desirable parents for establishing new breeding population.
The success of any crop breeding programme largely depends on the availability of huge genetic variability, genetic advance and character association, direct and indirect effects on yield and its attributes (Nwangburuka et al., 2012).
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