Thesis Abstract

Thesis Overview

<p> </p><div><p>An effort to obtain a tomato cultivar that would adapt to high temperature and high humidity<br>condition in the southern part of Nigeria in order to increase tomato yield in this part<br>of the country has been in progress for the past nine years (2000-2008).The research<br>was carried out at the Faculty of Agriculture Research Farm, University of Nigeria,<br>Nsukka located in the derived savanna zone latitude 0.6o52, N, longitude 07o 24, E,<br>447.26 m altitude. Three cultivated tomato varieties (Solanum lycopersicon) Roma<br>VF, Tropica (Derica), Nsukka Local and a wild relative, Solanum pimpinellifolium<br>and their progenies were used in the study for the development of a novel tomato<br>cultivar for commercial production. The results of the frequency distributions of the<br>parents and progenies showed continuous variation in fruit size thus suggesting fruit<br>size in tomato as a polygenic trait that is controlled by multiplicative gene action.<br>Genetic progress made over the generations equally revealed that highest genetic gain<br>was obtained at the F11 generation over all the generations studied with a decline at<br>the F12 generation.</p><p>Correlation coefficients revealed positive associations between<br>yield and all the yield components in all the generations. Path coefficient analysis<br>showed that number of flowers per plant had the highest direct effect on yield.<br>Principal component analysis had number of flowers per plant and fruits per plant as<br>the highest weighting factors. Genotype by trait (GT) biplot analysis revealed that<br>Roma x Wild out performed the other hybrids for the yield traits measured. The<br>results of different statistical analyses performed rated Roma x Wild as the best<br>genotype among the three cross combinations (Roma x Wild, Local x Wild and<br>Tropica x Wild) that will replace the original parents for adaptability under high<br>humidity environment. Among the agronomic traits studied, number of flowers per<br>plant and number of fruits per plant were of considerable importance, thus selection<br>based on these traits will enhance yield in tomato. The genotype (Roma x Wild) gave<br>higher yield and was more tolerant to high humidity conditions.</p></div><h3></h3><br> <br><p></p>