Hierarchical and optimization methods or the characterization of tomato genotypes/Metodos hierarquicos e de otimizacao na caracterizacao de genotipos de tomateiro

• Published in: Revista brasileira de engenharia agrícola e ambiental 2019-01, Vol.23 (1), p.27
• Main Authors: Peixoto, Joicy V.M, de Almeida, Rafaela S, Rocha, Jaine P.R. da, Maciel, Gabriel M, Santos, Nadya C, Pereira, Lucas M
• Format: Article
• Language: English
• ISSN: 1415-4366
• DOI: 10.1590/1807-1929/agriambi.v23n1p27-32

The correct characterization of germplasm banks is fundamental for breeders to succeed in breeding programs. Several studies have sought to obtain genotypes with resistance to pests. However, there is no consensus about which methodology is the most appropriate to characterize a germplasm bank of tomato with different levels of resistance to pests. The objective of this study was to compare methods of multivariate analysis for the evaluation of genetic diversity in tomato genotypes with different levels of resistance to pests. The experiments were conducted at the Vegetable Experimental Station of the Federal University of Uberlandia --Monte Carmelo campus (18[degrees] 42' 43.19" South latitude and 47[degrees] 29' 55.8" West longitude, 873 m altitude), in the period from April 2013 to November 2016. Sixteen genotypes were evaluated from the interspecific cross between LA-716 (S. pennellii) versus pre-commercial line (UFU-057) followed by backcrossing and self-fertilization, along with the pre-commercial line UFU-057 (recurrent parent) Santa Clara and the wild accession S. pennellii (donor genitor). The contents of acylsugar, foliar trichomes, South American tomato pinworm and leaf miner repellency tests were analyzed. The experimental design was the randomized block design totaling 76 plots (19 genotypes x 4 blocks). It was concluded that there was genetic variability among the evaluated genotypes. The method of graphic dispersion by principal components revealed a greater power of discrimination. Genotypes UFU-057[F.sub.2]R[C.sub.2]7#4.3, UFU-057[F.sub.2]R[C.sub.2]8#2.2 and UFU-057[F.sub.2]R[C.sub.2]7#4.7 contain the highest levels of acylsugar, resistance to Liriomyza spp. and T absoluta. Key words: tomato, insect resistance, multivariate analysis Uma correta caracterizacao de bancos de germoplasma e fundamental para melhoristas obterem sucesso em programas de melhoramento. Varias pesquisas tem buscado obtencao de genotipos com resistencia a pragas. No entanto, nao ha um consenso em relacao a qual metodologia e a mais adequada para caracterizar um banco de germoplasma de tomateiro com diferentes niveis de resistencia a pragas. O trabalho foi realizado com o objetivo de comparar metodos de analise multivariada para avaliacao da diversidade genetica em genotipos de tomateiro com diferentes niveis de resistencia a pragas. Os experimentos foram conduzidos na Estacao Experimental de Hortalicas da Universidade Federal de Uberlandia--campus Monte Carmelo (18[de