CHAPTER ONE

INTRODUCTION

Background to the Study

Eggplant (Solanum melongena L.; Division Anthophyta; Class Dicotyledoneae; Order Solanales) is an agronomically important non-tuberous solanaceous crop grown primarily for its large oval fruit. Eggplant is native to India and China and was probably introduced to Europe by Arabic traders and then brought to North America by early European settlers. In popular medicine, eggplant is indicated for the treatment of several diseases, including diabetes, arthritis, asthma and bronchitis.

In addition, several groups have provided evidence that eggplant extracts have a significant effect in reducing blood and liver cholesterol rates in humans (Khan 1979; Jorge et al. 1998) and adult rats (Silva et al. 1999). Nasunin, a major component of anthocyanin pigment of eggplant, has been shown to inhibit lipid peroxidation (Igarashi et al. 1993). More recently, free radical scavenging and iron chelating activities of nasunin were demonstrated by electron spin resonance (Noda et al. 1998; 2000). Furthermore, anti-mutagenic activity of pheophytin components from eggplant fruit extracts acting against several chemical mutagens was demonstrated by the Salmonella/microsome assay (Yoshikawa et al. 1996a; 1996b).

Eggplant is susceptible to several diseases and pests that cause serious crop losses. This problem has been addressed by hybridizing eggplant with wild resistant Solanum species, which present a wide genetic diversity and are source of useful agronomic traits. However, this approach is limited by sexual incompatibilities (Collonier et al. 2001) and difficulties in obtaining fertile progenies (Gleddie et al. 1986). In addition, traditional improvement methods may be hampered by the scarcity of natural resistance sources for some important diseases, impairing the obtention of resistant varieties (O’Brien 1983; Melo & Costa 1985; Lin & Xiao 1995). For example, no natural resistance sources are known for anthracnosis (Colletotrichum gloeosporioides), southern wilt (Ralstonia solanacearum) and the most common fungal disease of eggplant in Brazil, the Verticillium wilt (Verticillium dahliae).

Eggplant fruits are subject to attack by fungal pathogens leading to postharvest rots and diseases.

Solanum L., a complex and large genus of the family Zacharia and Philip [Philip,2010] and Gambari et al. [10] isolated Solanaceae has several species which are referred to as           Alternaria solani, Fusarium solani, Colletotrichum eggplant or African garden egg [Daunay,2001]. Eggplant is one of the gloeosporioides, Botrytis cinerea, Penicillium sp.,most commonly consumed fruit vegetables in tropical Rhizopus nigricans, Curvularia lunata, Botryodiplodia . Africa, in quantity and value probably third after tomato theobromae, Mucor sp., Rhizoctonia solani  and onion [Grubben,2004].

They constitute important fruit and leafy Aspergillus niger from rotten fruits of eggplant.vegetables and provide dietary  supplements  especially, Alternaria solani, A. alternata, A. flavus, M. hiemalis in China, India, South East Asia and other West African and R. stolonifer were identified [Sumera,2009] to be associated countries [Doganlar,2002]. Some of these species are important for their and  responsible  for  spoilage  of  eggplant. The fungal medicinal qualities [Chinedu,2011]. These nutritional and medicinal pathogens isolated as the causative agents of eggplant benefits have helped enhance their wide-spread fruit rot were Phomopsismelongenae  and cultivation across continents and cultural boundaries [Grubben,2004]. Collectotrichumme longenae [Akwaji,2016]. Naureen et al. [Naureen,2009]

Fifteen species are commonly found in  Nigeria [Gbile,1985] reported that Fusarium solani, Geotrichum sp. And out of which Solanum melongena L.,S.ethiopicum Phytophthora capsici were responsible for postharvest L. and S. macrocarpon L. are the most popular [Danny;Oyelana,2009].

Statement of Problem

Eggplant is susceptible to several diseases and pests that cause serious crop losses. This problem has been addressed by hybridizing eggplant with wild resistant Solanum species, which present a wide genetic diversity and are source of useful agronomic traits. However, this approach is limited by sexual incompatibilities (Collonier et al. 2001) and difficulties in obtaining fertile progenies (Gleddie et al. 1986). In addition, traditional improvement methods may be hampered by the scarcity of natural resistance sources for some important diseases, impairing the obtention of resistant varieties (O’Brien 1983; Melo & Costa 1985; Lin & Xiao 1995). For example, no natural resistance sources are known for anthracnosis (Colletotrichum gloeosporioides), southern wilt (Ralstonia solanacearum) and the most common fungal disease of eggplant in Brazil, the Verticillium wilt (Verticillium dahliae).

Brinjal crop is subjected to the attack of many diseases which causes damage in all growth stages limiting production. The diseases are caused by fungi, bacteria, viruses, nematodes or environmental factors. Among them fungal and bacterial diseases are 5 common in brinjal fields. Common fungal diseases of eggplants include the Dampingoff caused by (Pythium sp, Rhizoctonia solani), Alternaria leaf spot caused by Alternaria melongenae, Cercospora leaf spot caused by Cercospora melongenae, Phomopsis blight or fruit rot caused by Phomopsis vexans and Fusarium wilt caused by Fusarium oxysporum f.sp melongenae. Out of them Phomopsis fruit rot caused by Phomopsis vexans and Fusarium wilt caused by Fusarium oxysporum f.sp. melongenae are the most devastating diseases of brinjal growing fields. The major economic part of the brinjal plant is the fruit only and the fruit is heavily infected mainly by fungal pathogen i.e. Phomopsis vexans (Das, 1998; Khan, 1999). The cultivators and the retail sellers are facing heavy economic losses on account of fruit rotting during cultivation.

RESEARCH OBJECTIVES

The specific objectives were to:

1.To document farmers’ knowledge on field and post-harvest diseases of yam.

2.To establish the pathogenicity of fungal organisms associated with tuber rots of white yam varieties.

3.To study the effectiveness of some chemical fungicides in reducing yam tuber rot in storage.

4.To study the effectiveness of some botanical extracts in controlling yam tuber rot fungi.

RESEARCH QUESTIONS

1.What is farmers’ knowledge on field and post-harvest diseases of yam.

2.What is the pathogenicity of fungal organisms associated with tuber rots of white yam varieties.

3.What is the effectiveness of some chemical fungicides in reducing yam tuber rot in storage.

4.What is the effectiveness of some botanical extracts in controlling yam tuber rot fungi.

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