Capsicum species are very important in Brazil because of economic, cultural and biological factors, and the country is considered to be a diversity center for this genus. Collection and maintenance of the genetic diversity in Capsicum are important to avoid genetic erosion. Besides the identification of species, the characterization and evaluation of accessions maintained in gene banks are of fundamental importance. For this purpose, multivariate methods have become an important tool in the classification of conserved genotypes. The objectives of this study were: i) to identify and characterize accessions of the Capsicum spp collection and draw conclusions about the potential use of certain accessions in different production sectors; ii) to estimate the genetic divergence among accessions using the Ward-MLM procedure, and iii) to evaluate the efficiency of the analysis of continuous and categorical data using the Ward-MLM procedure. Fifty-six Capsicum spp accessions were evaluated based on 25 descriptors, 14 of which were morphological and 11 agronomic. Based on the qualitative descriptors, it was possible to identify all species and, together with the agronomic descriptors, genotypes could be indicated with potential for use in various production sectors. Five was determined as the ideal number of groups by the criteria pseudo-F and pseudo-t 2 . The Ward-MLM procedure allowed the differentiation of the species C. annuum, C. frutescens, C. baccatum, and C. chinense in separate groups. The Ward-MLM procedure showed some level of efficiency in clustering Capsicum species analyzing morphological and agronomic data simultaneously.

ABSTRACT. Accessions in gene banks need to be characterized and evaluated to determine their genetic diversity. We made a joint diversity analysis of the tomato gene bank of the Universidade Estadual do Norte Fluminense Darcy Ribeiro in Rio de Janeiro State, using the Ward-modified location model. Forty Solanum lycopersicum accessions were characterized and evaluated for 22 morphoagronomic descriptors and 131 random amplified polymorphic DNA markers. Based on the pseudo-F and pseudo-t 2 criteria, the optimal number of groups was established as five. Variability within groups was high for Divergence among tomatoes using Ward-MLM both continuous and discrete nominal data. The first two canonical variables explained about 90% of the inter-group variability. Care should be taken in using the Ward-modified location model technique to avoid incorporating excessive and unnecessary markers, which could favor molecular markers when compared with morphoagronomic variables. However, the minimum number of markers is germplasm-dependent and must be recalculated for each new divergence analysis.

ABSTRACT. Use of multivariate statistical algorithms is considered an important strategy to quantify genetic similarity. Local varieties and traditional (heirloom) seeds of genotypes are key sources of genetic variation. The Universidade Estadual do Norte Fluminense (UENF), Rio de Janeiro, Brazil, has a tomato gene bank with accessions that have been maintained for more than 40 years. We compared various algorithms to estimate genetic distances and quantify the genetic divergence of 40 tomato accessions of this collection, based on separate and joint analyses of discrete and continuous variables. Differences in continuous variables and discrete and joint analyses were calculated based on the Mahalanobis, Cole Rodgers and Gower distances. Although opinions differ regarding the validity of joint analysis of discrete and continuous data, we found that analyzing a larger number of variables together is viable and can help in the discrimination of accessions; the information that is generated is relevant and promising for both, the accessions conservation and the use of genetic resources in breeding programs.

BackgroundThionins are a family of plant antimicrobial peptides (AMPs), which participate in plant defense system against pathogens. Here we describe some aspects of the CaThi thionin-like action mechanism, previously isolated from Capsicum annuum fruits. Thionin-like peptide was submitted to antimicrobial activity assays against Candida species for IC50 determination and synergism with fluconazole evaluation. Viability and plasma membrane permeabilization assays, induction of intracellular ROS production analysis and CaThi localization in yeast cells were also investigated.ResultsCaThi had strong antimicrobial activity against six tested pathogenic Candida species, with IC50 ranging from 10 to 40 μg.mL−1. CaThi antimicrobial activity on Candida species was candidacidal. Moreover, CaThi caused plasma membrane permeabilization in all yeasts tested and induces oxidative stresses only in Candida tropicalis. CaThi was intracellularly localized in C. albicans and C. tropicalis, however localized in nuclei in C. tropicalis, suggesting a possible nuclear target. CaThi performed synergistically with fluconazole inhibiting all tested yeasts, reaching 100 % inhibition in C. parapsilosis. The inhibiting concentrations for the synergic pair ranged from 1.3 to 4.0 times below CaThi IC50 and from zero to 2.0 times below fluconazole IC50.ConclusionThe results reported herein may ultimately contribute to future efforts aiming to employ this plant-derived AMP as a new therapeutic substance against yeasts.

Popcorn breeding programs in Brazil have emerged but despite some advances there is still a lack of material performance studies specially regard to seed quality, in different agricultural seasons. This research was carried out to estimate the popcorn combining ability from biparental crosses between eight tropical and one temperate lines in two agricultural seasons (2008 and 2009) with regard to eight traits related to seed quality, in addition to three agronomic traits related to popping expansion. Method 4, proposed by Griffing (Model 1), was used to verifying the importance of the dominance effect in the genetic control of the seed quality traits, favouring the identification of superior hybrids through seed tests in the laboratory with low cost. The lines from Zélia and CMS42 were promising in obtaining hybrids with superior seed quality and greater popping expansion. The hybrids Zélia 9 IAC-112, CMS42 9 UEM M2-1, CMS43-1 9 IAC-112 and UEM M2-2 9 Zaeli expressed superior SCA for grain yield, popping expansion and at least two seed quality traits. These hybrids are materials of interest for cultivation in different planting seasons.

E studos de divergência genética são importantes para o conhecimento da variabilidade genética das populações e possibilitam o monitoramento de bancos de germoplasmas (Cruz e Carneiro, 2003), pois geram informações úteis para preservação e uso dos acessos (Toquica et al., 2003 et al., 1998). Marshall (1989), estimou que 0,5% dos acessos de um banco devem ser requisitados por ano, e considerou que este seria o uso mínimo desejável. Porém, isto dificilmente acontece, e segundo Li et al. (1998), os fatores que dificultam o uso do banco de germoplasma são a não disponibilidade dos acessos aos melhoristas, a falta de conhecimento sobre os acessos conservados e o não conhecimento dos curadores sobre os programas realizados pelos melhoristas. Hammer (2003), afirma que um banco de germoplasma não pode ser um museu, devendo-se estimular a avaliação dos acessos por meio de análises genéticas.Para determinar quão distante geneticamente uma população ou genótipo é de outra são utilizados métodos biométricos, onde se quantifica ou se estima a heterose, que são analisados pela estatística multivariada permitindo unificar múltiplas informações de um conjunto de caracteres. Vários métodos podem ser utilizados, dentre eles estão a análise por componentes principais, variáveis canônicas e métodos aglomerativos. A escolha do método RESUMOTécnicas multivariadas foram utilizadas para avaliar a divergên-cia genética entre 56 acessos da coleção de germoplasma de Capsicum spp. da UENF. Foram utilizados onze descritores quantitativos propostos pelo International Plant Genetic Resources Institute, em um experimento conduzido em condições de campo, em Campos dos Goytacazes (RJ), no delineamento de blocos ao acaso com três repetições e 10 plantas por parcela. A distância generalizada de Mahalanobis (D 2 ) foi utilizada como medida de dissimilaridade. Foram aplicadas variáveis canônicas, método hierárquico do vizinho mais próximo, método de otimização de Tocher e projeção das distâncias no plano. As variáveis avaliadas foram comprimento e diâmetro do fruto, número de sementes por fruto, peso médio do fruto, altura de planta, diâmetro da copa, peso de 1000 sementes, dias para florescimento, dias para frutificação, número de frutos por planta e peso de frutos por planta. Houve diferença significativa entre os acessos para todos os descritores avaliados. Observou-se concordância entre todas as técnicas multivariadas utilizadas e foi possível separar os acessos em oito grupos distintos, indicando a existência de variabilidade genética entre os acessos. A maior distância generalizada de Mahalanobis foi 266,42. Observou-se que acessos têm potencial para serem utilizados como genitores em cruzamentos para obtenção de progênies com alta heterose. Pela análise das variáveis canônicas observou-se que os cruzamentos com maior potencial heterótico seriam 56x43, 34x08 e 59x41.Palavras-chave: Capsicum spp., germoplasma, variáveis canônicas, método de Tocher, projeção das distâncias no plano, recursos genéticos.

ABSTRACT. Capsicum species are frequently described in terms of genetic divergence, considering morphological, agronomic, and molecular databases. However, descriptions of genetic differences based on anatomical characters are rare. We examined the anatomy and the micromorphology of vegetative and reproductive organs of several Capsicum species. Four Capsicum accessions representing the species C. annuum var. annuum, C. baccatum var. pendulum, C. chinense, and C. frutescens were cultivated in a greenhouse; leaves, fruits and seeds were sampled and their organ structure analyzed by light and scanning electronic microscopy. Molecular accession characterization was made using ISSR markers. Polymorphism was observed among tector trichomes and also in fruit color and shape. High variability among accessions was detected by ISSR markers. Although the species studied Characterization of Capsicum species present a wide morphological and molecular variability, this variability was not reflected in anatomical features.

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