Investigation of trichomes as defence structures against plant pests in different tomato cultivars

Tomato cultivation in our country has a great importance in terms of nutrition and economic return. One of the most important problem of tomato cultivation is yield losses caused by insect and mite pests. Although some tomato cultivars resistant to root diseases and nematodes of tomato plantshave been licensed, there is no registered resistant variety against mite and insect pests. One of the most important defensive structures are glandular and unglandular trichomes found in leaves, stems and branches of tomato plants, because they are negatively affect the insect and mite damage and even the activity of natural enemies. Particularly, 2-tridecanone (2-TD), from the methyl-ketone group in the content of glandular trichomes, zingiberene from sesquiterpenes and acylsugar from polyesters have a great role in the plant defense mechanism. Therefore, in this thesis study, trichome structures of 29 tomato cultivars were investigated. By determining the types and densities of trichomes in the examined cultivars, it is aimed to provide information that will form the basis for hybridization studies of both potential resistant cultivars and tomato cultivars resistant to pests in the future. Also, trichome densities have got particular importance due to limiting the effectiveness of some natural enemies (phytoseiid mites). According to the results of this thesis study; the densities of both unglandular thichomes, TYPE III and TYPE V, and glandular trichomes, TYPE IV and TYPE VI, in the examined in different tomato cultivars. When leaves, stems and branches are evaluated separately; it was determined that trichome types and densities differed significantly according to the cultivars. According to cluster analysis, trichome densities were grouped as low, medium and high. In this study, the trichome densities of each cultivar were shown. The findings will provide basic data for both cultivar resistance and biological control.