Selection of okra parents based on performance and genetic divergence

A total of 200 okra accessions with wide variability and a potential for genetic improvement were stored in the Vegetables Germplasm Bank of the Federal University of Viçosa (UFV-BGH) in Viçosa, Minas Gerais State, Brazil. The objective of this work was to select parents by genetic divergence and behavior per se in 70 okra accessions from the BGH-UFV by quantitative and qualitative descriptors of economic interest. Analysis of individual and combined variance, by clustering of means by Scott-Knott test, of the accessions by Tocher’s method and selection based on qualitative descriptors and behavior per se using the methodology of sum of inverted positions was made. The variability of the characteristics of the accessions as verified by the Scott-Knott test formed different groups and subgroups by Tocher’s method. Fifteen accessions were selected with the qualitative descriptors, and based on the sum of inverted positions for quantitative descriptors the BGH-132, BGH-547, BGH-693, BGH-740, BGH-961, BGH-7863, BGH- 7865, BGH-3196 and BGH-4890 okra accessions were selected as potential parents.Key words: Abelmoschus esculentus (L.) Moench, germplasm bank, genetic resource, genetic improvement

Classificação multivariada de curvas de progresso da requeima do tomateiro entre acessos do banco de germaplasma de hortaliças da UFV

O objetivo deste trabalho foi apresentar uma metodologia de análise de experimentos em fitopatologia que considera a comparação de curvas de progressos de doenças na presença de um grande número de tratamentos por meio da análise de cluster. Foram cultivados 42 acessos do Banco de Germoplasma de Hortaliças (BGH) da Universidade Federal de Viçosa (UFV). Ajustou-se o modelo exponencial aos dados de percentagem de severidade de requeima, e as estimativas obtidas quanto à incidência inicial da doença (yo) e taxa de progresso da doença (r) foram submetidas à análise de variância multivariada (Manova), seguindo o delineamento de blocos casualizados. As médias ajustadas foram submetidas à análise de agrupamento hierárquico, o método centroide. Observou-se um número ótimo de seis grupos distintos.The objective of this paper was to present a methodology for the analysis of experiments in plant pathology that considers the comparison of disease progress curves in the presence of a large number of treatments by cluster analysis. Forty-two accessions were grown from the Germoplasma Vegetable Bank (BGH), of Universidade Federal de Viçosa (UFV). The exponential model was fitted to the data of late blight severity percentage, and the obtained parameter estimates obtained on the initial incidence of the disease (yo) and rate of disease progression (r) - were submitted to the multivariate analysis of variance (MANOVA). The adjusted means were submitted to the cluster analysis. An optimal number of six distinct groups was observed

Characterization of the resistance of tomato accessions from the bgh-ufv to the geminivírus tomato yellow spot virus

The viruses transmitted by whiteflies are among those causing relevant losses in tomato cultivation. Among the measures to control these agents, introducing genes for resistance constitutes the main control measure, together with vector control. The objective of this work was to screen for sources of natural resistance to Tomato yellow spot virus (ToYSV) in S. lycopersicum germplasm from the Banco de Germoplasma de Hortaliças (BGH) of the Universidade Federal de Viçosa (UFV), Minas Gerais, Brazil. The 99 accessions and two susceptible controls were inoculated using biolistics. Inoculated plants were grown under greenhouse conditions. The percentage of plants displaying virus symptoms was evaluated at 10, 20 and 30 days after inoculation (DAI). Virus presence or absence in the inoculated plants was confirmed by hybridization with probes labeled with á-[32P]-dCTP, for each evaluation date. Inoculated plants produced typical disease symptoms showing different behavior on the genotypes in relation to ToYSV. Some of the evaluated genotypes showed higher virus tolerance compared to two susceptible controls, in particular the accessions BGH-2039V and BGH-2041 which showed no symptoms and no viral DNA accumulation in 80% of the inoculated plants at 30 DAI. The results suggest that the selected tomato accesses are good sources of resistance to new tomato cultivars tolerant to ToYSV.Os vírus transmitidos por moscas brancas estão entre aqueles que causam perdas relevantes na cultura do tomate. Entre as medidas para o controle desses agentes, a introdução de genes de resistência constitui a principal medida de controle, juntamente com o controle de vetores. O objetivo deste trabalho foi procurar fontes de resistência natural ao Tomato yellow spot virus (ToYSV) em germoplasma de S. lycopersicum do Banco de Germoplasma de Hortaliças (BGH) da Universidade Federal de Viçosa (UFV), Minas Gerais, Brasil. Noventa e nove subamostras e dois controles suscetíveis foram inoculados usando biobalística. As plantas inoculadas foram mantidas em casa de vegetação. A porcentagem de plantas exibindo sintomas do vírus foi avaliada aos 10, 20 e 30 dias após a inoculação (DAI). A presença ou ausência do vírus nas plantas inoculadas foi confirmada por hibridização com sondas marcadas com á-[32P]-dCTP, para cada data de avaliação. Plantas inoculadas produziram sintomas típicos da doença mostrando diferentes comportamentos dos genótipos em relação ao ToYSV. Alguns dos genótipos avaliados apresentaram maior tolerância ao vírus em relação aos dois controles suscetíveis, em particular as subamostras BGH-2039V e BGH-2041, que não apresentaram sintomas e no tinham acúmulo de DNA viral em 80% das plantas inoculadas aos 30 DAI. Os resultados sugerem que as subamostras de tomate selecionadas são boas fontes de resistência para novas cultivares de tomateiro tolerantes ao ToYSV