Multivariate techniques in the determination of genetic diversity in pest-resistant mini tomato genotypes

ABSTRACT The objective of this study was to compare methods of multivariate analysis on the evaluation of genetic diversity of mini tomato and to identify promising genotypes with resistance to pests. The experiment was conducted at the Vegetable Experiment Station of the Universidade Federal de Uberlândia, Monte Carmelo campus, from April 2013 to November 2016. The experimental design was a randomized complete block design with 16 treatments and four replications totaling 64 plots, and each plot represented by five plants. Sixteen genotypes were characterized, 12 from the F2RC1 generation, obtained through the interspecific crossing between the wild access LA-716 (Solanum pennellii) and pre-commercial lines of mini tomato (UFU-73 and UFU-2) (Solanum lycopersicum) and the UFU-2 lines. The content of acyl sugar, the amount of glandular trichomes (types I, IV, VI and VII), twospotted spider mite and whitefly resistance were evaluated. We concluded that there exist genetic variability between the genotypes. The number of groups formed by the canonical variated analysis was higher (four groups) than that obtained by the Tocher method (three groups) and UPGMA (three groups), demonstrating a greater discrimination power. The Tocher and UPGMA methods were consistent in the analysis of the genetic divergence in pest resistant germplasm of tomato, with the acyl sugar content being the most important variable. Genotype UFU-73-F2RC1 # 11 is resistant to pest attack, while the other studied lines have intermediate resistance.摘要 本研究旨在比较多元分析方法在微型番茄遗传多样性评价中的应用，并筛选出具备抗虫性的优良基因型。试验于2013年4月至2016年11月在乌贝兰迪亚联邦大学蒙泰卡梅卢校区蔬菜试验站开展。试验采用随机完全区组设计，共设置16个处理、4次重复，总计64个试验小区，每个小区种植5株供试植株。供试基因型共16份：其中12份为F2RC1代群体，由野生种质LA-716（潘那利番茄，*Solanum pennellii*）与微型番茄预商用品系UFU-73、UFU-2（普通番茄，*Solanum lycopersicum*）经种间杂交获得；剩余4份为UFU-2品系。本试验测定了酰基糖含量、I、IV、VI、VII型腺毛数量，以及二斑叶螨和烟粉虱抗性水平。结果表明，供试基因型间存在显著遗传变异。典范变量分析划分的群组数（4组）多于托彻法（3组）与非加权组平均法（UPGMA，3组），显示典范变量分析具备更高的判别能力。托彻法与UPGMA法在番茄抗虫种质的遗传差异分析中结果一致，其中酰基糖含量是最为关键的评价指标。基因型UFU-73-F2RC1 #11对害虫为害具有抗性，其余供试品系均表现为中等抗性。