Genotypic variation of Kenyan tomato (Lycopersicon esculentum L.) germplasm

Abstract

Systematic genotypic analysis of Kenyan tomato germplasm was carried out in order to delineate potential variability based on various morphological, agronomic and biochemical traits. Both landraces and market cultivars were examined with a view to facilitating tomato improvement. In an experiment conducted in 1993 in a glasshouse at the Federal Agriculture Research Centre (FAL), Germany, 26 tomato landraces and nine market cultivars were investigated using block design. Analysis of variance clearly illustrated a large variation for all the quantitative traits. Landraces on average produced more fruit per plant (90) but of a smaller size than the market cultivars (19). However, market cultivars had a superior average fresh fruit weight of 56.5g while the landraces registered on average 40.6 g. Multiple correlation analysis confirmed the superiority of landraces for trait of fruit quality and a strong negative association between fruit weight. Limited structure groupings were detected on the basis of a principal components analysis. Using this method, processing and fresh tomato cultivars within the germplasm could be clearly separated on the basis of fruit characters. Furthermore, this analysis distinguished a few landraces from the market cultivars, although closer phylogeny through introgression was highly suspected. Within the landraces, the yellow-cherry types were distinct from all the others, On the basis of this study, the use of more prolific landraces, in terms of number of fruit as well as actual fruit yield, would be desirable for intensive and continuous production of tomatoes.