ACESSOS SILVESTRES E LINHAGENS COMERCIAIS DE TOMATEIRO: ANÁLISE MORFO-ANATÔMICA, GERMINAÇÃO, RESISTÊNCIA À PRAGAS E ESTUDO DE DIVERSIDADE

Abstract

The tomato plant is considered the second most important economic and food vegetable in the world. Among the factors that most contributed to the increase in the production of this fruit is genetic improvement, o it provides better quality of fruit, greater productivity in different climatic conditions, in addition to greater resistance to pests and diseases, among other aspects. Therefore, the characterization of these materials is of great importance, o it provides important information that can be used in choosing the best parents for crosses and hybridization. Seed germination of some wild tomato species is perhaps the first impasse in the breeding program, considering the physiological processes of dormancy commonly observed. An example of this is the wild material Solanum galapagense, which has low germination. Thus, there is a need for joint use of scarification techniques and use of plant regulator. In the present research, 80% of germination was obtained for the LA-1401 genotype using scarification by sodium hypochlorite and Stimulate®. Another important factor for improvement projects is the identification of resistance in wild materials to pests. Thirty-six genotypes were tested, including table tomato, cherry, processing, isogenic table tomato strains and 24 wild tomato genotypes, from 8 different species, for resistance to whitefly (Bemisia tabaci). In 4 evaluations with a difference of 10 days between each one, the materials Solanum pennellii LA-716, Solanum habrochaites PI-247084 and Solanum galapagense LA-1401, proved to be the most resistant with the lowest number of eggs and nymphs on the leaf surface. The analysis of the principal components and the correlation of trichome data showed that wild materials and the isogenic strains UEL M-12 and UEL-M15 have greater resistance to whitefly, mainly due to the presence of type IV glandular trichomes. For resistance to tomato moth, 13 different tomato genotypes were tested, 9 wild and 3 commercial species. These results were correlated with the presence of glandular trichomes. The genotypes with the highest resistance were those with the highest number of glandular trichomes on the leaf surface, S. pennellii, S. habrochaites var. hirsutum. Commercial materials, despite having a high density of tector trichomes, did not perform well in resistance tests, proving that tector trichomes are not effective in defending against this pest. In the morphoanatomical analysis of 12 accessions between 9 wild and 3 commercial, the main differences found were the presence of vesicles in the parenchyma of some species that were not present in others, varying in quantity between the species where they appeared, they were in greater quantity in the genotypes of S. peruvianum and S. lycopersicum var. wax-like. The most common trichomes found in the studied accessions were the type VI glandular and the type V tector, the type IV glandular trichomes were only present in the species that presented greater resistance to pests. With the study of the diversity of tomato species from the UEL/UNICENTRO germplasm bank with 70 different genotypes, it was concluded that the Brazilian commercial tomato and cherry strains have different characteristics in relation to the materials cultivated and studied in other parts of the world. Through the diversity study carried out, it was possible to infer that S. lycopersicum has low similarity with the materials of S. lycopersicum var. cerasiforme and S. peruvianum. Despite being distant from other species, S. peruvianum may have contributed to the diversity of the Brazilian cerasiforme, a relationship that can still be better explored.