Thesis Abstract

Abstract
Okra (Abelmoschus esculentus (L.) Moench) is an important vegetable crop grown widely in the Northern Guinea Savannah of Nigeria. The response of okra varieties to varying rates of poultry manure and stand density is crucial for optimizing yield and quality. This study aimed to evaluate the growth, yield, and quality attributes of four okra varieties (NHAE-47, NHAE-48, NHAE-50, and NHAE-52) under different poultry manure rates (0, 5, and 10 t ha-1) and stand densities (20 cm × 20 cm, 30 cm × 30 cm, and 40 cm × 40 cm) in a randomized complete block design with three replications. The results showed that the NHAE-50 variety recorded the highest plant height, number of leaves, stem girth, and leaf area compared to the other varieties. Additionally, increasing poultry manure rates significantly influenced plant height, stem girth, leaf area, and fresh fruit yield. The application of 10 t ha-1 of poultry manure resulted in the highest values for these parameters. Stand density also had a significant effect on plant height, stem girth, leaf area, and fresh fruit yield, with the widest spacing (40 cm × 40 cm) generally outperforming the narrower spacings. Furthermore, the NHAE-50 variety combined with a poultry manure rate of 10 t ha-1 and a stand density of 40 cm × 40 cm exhibited the best performance in terms of growth, yield, and quality attributes. This treatment combination resulted in the highest fresh fruit yield per hectare compared to other treatments. In conclusion, the response of okra varieties to poultry manure rate and stand density in the Northern Guinea Savannah demonstrated the importance of variety selection and appropriate nutrient management practices for optimizing yield and quality. The NHAE-50 variety, combined with a poultry manure rate of 10 t ha-1 and a stand density of 40 cm × 40 cm, showed promising results for sustainable okra production in the region. This study provides valuable information for okra farmers and researchers to enhance productivity and profitability in okra cultivation through improved management practices.

Thesis Overview

INTRODUCTION

1.1         Origin and Distribution of Okra

Okra (Abelmoschus esculentus(L.)Moench)originated in Ethopia in the year 120 BC. It is a common vegetable in tropical and sub-tropicalcountries, native to west and central Africa. It is known as a fast growing annual vegetable commonly grown in field and home gardens in Africa (Fayemi, 1999and Schippers, 2000). It belongs to the family,Malvaceae and was domesticated in West and Central Africa (Kochhar, 1986). It is known as ‘Okro’ in the Anglophone African countries. Okra is cultivated throughout the tropical and warm temperate regions of the world for its fibrous fruits (N.R.C., 2006). Okra is mainly cultivated in African countries such as Nigeria, Sudan, Egypt, Niger and Cameroun. It is also important in other tropical areas including Asia and South America.

1.2         Soil and Climatic Requirement

A range of soil types have been found suitable for okra production even though it thrives best in moist, friable, well- drained soils. Sandy loam soils high in organic matter are the most desirable.A pH of about 6.0 – 6.8 is recommended for Okra production.In Nigeria, production is mainly during the rainy season. Okra requires a moderate rainfall of about 800-1000mm. Studies on the optimum weather requirement for high yields ofOkra showed that it performs best (growth, flowering and fruiting) when the minimum and maximum temperatures are between 200 and 300 celsius, respectively.Okra is sensitive to low temperature and develops poorly below 150 Celsius. The seeds germinate in relatively warm soils only(Tindall et al., 1986).

1.3         Production and Economic Importance of Okra

Okra ranks third in Nigeria in terms of production area andconsumption, following tomato and pepper in that sequence. India is the major producer of Okra, producing about 5,784, 000 metric tons per year (FAO, 2015). Production statistics of 2016 shows that Nigeria produces an estimated 1,978,286 tons ofOkra per annum,placing the country at second place after India.

In Nigeria, there are two distinct seasons for Okra production, the peak and lean seasons. During the lean season, okra fruit are produced in low quantities, scarce and expensive to get while in the peak season, it is produced in large quantities much more than the local populace can consume (Bamire and Oke, 2003).

The approximate nutrient content of edible Okra pod is as follows: water, 88%; protein, 2.1%; fat, 0.2%, carbohydrate, 8.0%; fiber, 1.7% and ash, 0.2% (Tindall, 1983).The green pods are rich sources of vitamins, calcium, potassium, and other minerals. In Nigeria, Okra is distributed and consumed either fresh (usually boiled, sliced or fried) or in a dried form (Fatokun and Chedda, 1983). Young leaves may also be used in cooked or processed forms. Fresh Okra fruits are used as vegetable while the roots and stems are used for preparing brown sugar (Chauhan, 1972). The protein found in Okra helps to build muscle tissue and constituent of enzymes which control all the hormone`s activities. The soluble fiber in Okra helps to lower serum cholesterol, reducing the risk of heart disease. The insoluble fiber helps to keep the intestinal tract healthy, reducing the risk of cancer especially colorectal cancer. Okra has also found medical application as a plasma replacement for the body.Nearly 10% of the recommended level of vitamin B6 and folic acid are present in half a cup of cooked Okra. The vitamin is required for good vision, proper circulation of blood, bone growth and normal digestion (Wolford and Banks, 2006). Okra is a good source of calcium which helps to keep bone strong and lessen the chance of fractures (Grubben and Denton, 2004). The seeds however can be roasted and used as substitute for coffee (Farinde and Owolarafe, 2007). Okra mucilage is used industrially for glace paper production and is also used in making confectionaries. (Akinyele and Temikotan, 2007).

Interestingly, Okra’s potential as an oilseed crop and its ability to tolerate drought in a world facing global climate change underscores its growing importance (Ibeawuchi, 2007). Oil content of Okra seed can be as high as that in poultry eggs and soybeans (Robert et al., 2011) Okra fruits are considered to be of good quality in the Nigerian context when they are smooth, small, narrow and highly mucilaginous. Fruits that have exceeded physiological maturity rarely give these characteristics and are generally not commonly consumed. They are frequently left on the plants to dry and then preserved for seeds (Splittstoessor, 1990). Fruits are often sliced and dried to ease preservation when it cannot be sold in the market and has become hard or tough and unsuitable for use in fresh form.