Genetic divergence of tomato subsamples

Abstract

RESUMO Divergência genética de subamostras de tomateiroPara o avanço de um programa de melhoramento genético é fundamental o conhecimento da variabilidade genética existente na espécie, o que demanda estudos de caracterização e avaliação do germoplasma disponível. Objetivou-se neste estudo a caracterização e avaliação de 101 subamostras de tomateiro do grupo Salada e duas testemunhas comerciais, uma do grupo Salada (cv. Fanny) e outra do grupo Santa Cruz (cv. Santa Clara). Foram realizados quatro experimentos no delineamento em blocos casualizados, com três repetições e cinco plantas por parcelas. Foram realizadas análises de variância conjunta e descartadas as características com interação significativa do tipo complexa entre testemunha e experimento. Posteriormente, foi realizado o diagnóstico de multicolinearidade e descartadas as Genetic divergence of tomato subsamplesUnderstanding the genetic variability of a species is crucial for the progress of a genetic breeding program and requires characterization and evaluation of germplasm. This study aimed to characterize and evaluate 101 tomato subsamples of the Salad group (fresh market) and two commercial controls, one of the Salad group (cv. Fanny) and another of the Santa Cruz group (cv. Santa Clara). Four experiments were conducted in a randomized block design with three replications and five plants per plot. The joint analysis of variance was performed and characteristics with significant complex interaction between control and experiment were excluded. Subsequently, the multicollinearity diagnostic test was carried out and characteristics that contributed to severe multicollinearity were excluded. The relative importance of each characteristics for genetic divergence was calculated by the Singh's method (Singh, 1981), and the less important ones were excluded according to Garcia (1998). Results showed large genetic divergence among the subsamples for morphological, agronomic and organoleptic characteristics, indicating potential for genetic improvement. The characteristics total soluble solids, mean number of good fruits per plant, endocarp thickness, mean mass of marketable fruit per plant, total acidity, mean number of unmarketable fruit per plant, internode diameter, internode length, main stem thickness and leaf width contributed little to the genetic divergence between the subsamples and may be excluded in future studies.

Hierarchical and optimization methods for the characterization of tomato genotypes

“…The Euclidean distance is estimated by average data, disregarding the residual variances and covariance between the measured attributes. The hierarchical method Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA) and the Tocher optimization method are routinely used in tomato for the estimation of genetic divergence (Mattedi et al, 2014;Araújo et al, 2016).…”

Performance of tomato rootstocks in False Root-knot Nematode (Nacobbus aberrans) infested soil

“…Over the last few decades, world production of tomatos has increased significantly, a fact that is not entirely unrelated to the significant increase in research over the same period. This research includes the creation and introduction of new production techniques focused primarily on increasing productivity, increasing the size of the fruit (Guimarães et al, 2008), achieving a variety of fruit shapes and colours (Mattedi et al, 2014), and increasing the period of postharvest conservation, among other factors. Although there have been important advances in tomato production, the crop still faces serious problems today, due to infestation by pests and diseases which cause high economic losses and make the tomato one of the vegetables that receive the highest amount of agricultural pesticides.…”

Prediction of industrial tomato hybrids from agronomic traits and ISSR molecular markers

“…Predictive techniques based on multivariate statistical procedures can estimate the genetic distance between parents, assisting the breeder in the definition of crosses between the most divergent parents by increasing the chances of developing a high-yielding hybrid in less time (Oliveira et al, 1998;Moreira et al, 2005;Gonçalves et al, 2008, Rocha et al, 2010Reddy et al, 2013, Mattedi et al, 2014.…”