Thesis Abstract

Abstract
Nematodes are microscopic worms that can have detrimental effects on the growth and yield of various crops, including tomatoes. In this study, we aimed to identify and isolate nematodes affecting tomato plants in order to develop effective management strategies. The research involved sampling soil and roots from tomato fields in different regions known for nematode infestations. Nematodes were extracted from these samples using established techniques such as centrifugal flotation and Baermann funnel extraction. Morphological and molecular techniques were employed to identify the nematode species present in the samples. Morphological characteristics such as body shape, size, and presence of structures like stylet and esophagus were used to initially classify the nematodes. Subsequently, molecular tools such as polymerase chain reaction (PCR) and sequencing of specific genetic markers were utilized for accurate species identification. The isolated nematodes were then subjected to bioassays to assess their pathogenicity towards tomato plants. This involved inoculating tomato seedlings with different concentrations of nematodes and monitoring plant growth and symptoms of nematode damage over time. The bioassays provided valuable information on the virulence of the nematode populations and their impact on tomato growth. Furthermore, the genetic diversity of the nematode populations was investigated using molecular markers. This information was crucial for understanding the genetic structure of the nematode populations and their potential for developing resistance to management strategies. By combining morphological, molecular, and bioassay data, we were able to develop a comprehensive profile of the nematodes affecting tomato plants in the studied regions. The findings of this study have important implications for tomato growers and agricultural stakeholders. By accurately identifying the nematode species and understanding their pathogenicity and genetic diversity, tailored management strategies can be implemented to mitigate nematode damage and improve tomato yield. This research contributes to the ongoing efforts to enhance sustainable tomato production by providing insights into nematode biology and interactions with tomato plants.

Thesis Overview

INTRODUCTIONNematodes are tiny, thread-like worms measuring 0.0 15 inch to 0.187 inch in length. They are either free living parasitic or saprophytic, identified on the basis of shapes, size and special structures. The females become swollen and flask-shaped as a result of accumulation of eggs with the anus virtually terminal in position, while the males are vermiform (Sherf and Macnah, 1986; Chitwood, 1949; Taylor and Sasser, 1978; Idowu, 1979 and Idowu, 1983)Nematodes are known for causing destructive diseases of crops as they have a wide range of feeding habit, constitute about 80% of all multicellular animals, attacking nearly every crop that is grown in the field and as a result crop yields is greatly affected reducing quantity and quality of crops on field, orchard, home garden and green houses (Mai, 1985; Symth, 1994; Sasser, 1952). Among the favoured host in Nigeria as a whole include tomato, yam, tobacco, papaw, citrus and sweet potato (Sasser, 1954).1.1 Tomato:Tomato (Lycopersicum esculentum) belongs to the family Solanaceae and subilass polypetalae of the dicotyledenous group of plants. Tomato is a slight modification of tomato the name used by the Indians of Mexico, who have grown the plant for food since prehistoric times. Other names reported by early European explorers were tomato, tumatle and tomatas, probably variants of Indian words (Wener, 2004).1.2 Origin:The precise origin of tomato remains a mystery but there is reason to believe that the original tomato came from Peru called tomato, it was taken to Mexico by migrating Peruvians. It found its way to Italy through the explorations of Christopher Columbus. Tomatoes were taken back to Europe along with silver and gold and they were grown on the continent as a pretty curiosity (Fallagatter, 1999.