Derly José Henriques da Silva

Screening of Lycopersicon sp. accessions for resistance to Pepper yellow mosaic virus

The tomato is a crop of great economical importance, however it is susceptible to a large number of pests and diseases, including viral disease for which the best control strategy is genetic resistance. The disease, caused by Pepper yellow mosaic virus (PepYMV) has become a recent problem. Consequently, the idea of this work was to screen 376 accessions of Lycopersicon sp. to find possible sources of resistance to PepYMV. Out of 355 accessions of L. esculentum inoculated with PepYMV, 52 did not express symptoms. However, the virus reached high concentration in the tissues as measured by indirect ELISA, and therefore they were not considered as safe sources of resistance. Among 21 accessions of wild Lycopersicon species, one of L. hirsutum was shown to be resistant, with no observed symptoms. A low concentration of the virus was detected as measured by indirect ELISA. This accession seems to be suitable for breeding programs aiming at incorporating resistance for this disease into commercial tomato cultivars.

Caracterização físico-química de frutos de quatro cultivares de quiabo

In an experiment some physical and chemical characteristics of four okra cultivars were evaluated. The experimental design was of randomized blocks, where the treatments were the cultivars Amarelinho, Red Velvet, Star of David and Mammoth Spinless with five replications. At commercial maturity fruits of the cultivar Star of David presented the largest diameter, total fresh matter, content of dry matter, smallest length, content of water and vitamin C in comparison to the other cultivars. The cultivar Red Velvet presented the smallest diameter, total fresh matter, content of dry matter, reducing sugars and content of chlorophyll a, b and total, but the largest content of water and vitamin C. The cultivar Amarelinho produced the longest fruits and the smallest content of chlorophyll a, b and total. The cultivars Amarelinho and Mammoth Spinless showed higher contents of total reducing sugars.

Divergência genética entre linhagens de melão pele de Sapo

The objective of this work was to study the genetic divergence among lines of Pele de Sapo melon evaluated in Mossoro-RN, Brazil. Twenty lines were evaluated in a randomized block design with three replications. The genetic divergence was evaluated by multivariate procedures: generalized distance of Mahalanobis, methods of grouping optimization of Tocher and UPGMA. The traits assessed were: The traits evaluated were: total number of fruits, productivity, average weight of fruits, transversal diameter, diameter longitudinal, format index, internal cavity, pulp thickness, pulp firmness, soluble solids content, concentration of harvesting and weight loss. There was partial concordance regarding the composition of the groups formed by the methods of optimizing Tocher and UPGMA. The traits that most contributed to the divergence have been pulp firmness (20.69%) and soluble solids (10.94%). The presence of genetic variability allowed the identification of cultivars dissimilar and with a mean high for the traits studied. The crosses suggested in the study of genetics divergence were: SA-13 x TH-03, SA-13 x TH-04, SA-13 x TH-05, SA-13 x TH-07, SA-13 x TH-09, SA-13 x SA-17, TH-05 x TH-04, TH-05 x SA-10, TH-05 x SA-12, TH-05 x SA-14 and TH-05 x SA-14.

Fontes de resistência em tomateiro aos begomovírus bissegmentados Tomato yellow spot virus e Tomato severe rugose virus

Begomoviruses cause diseases of major economic importance in many crops, especially in tropical and subtropical regions. Together with other families of viruses, the begomoviruses cause great damage for producers of fresh and processed tomatoes. The objective of this study was to evaluate the behavior of 11 resistant genotypes to Tomato yellow leaf curl virus (TYLCV) when infected by the begomoviruses Tomato severe rugose virus (ToSRV) and Tomato yellow spot virus (ToYSV) under greenhouse conditions. Tomato plants were inoculated by biobalistic method when displaying two true leaves. Viral infection was confirmed by visual observation of symptoms and by dot blot hybridization. Genotypes STY2, STY5, STY6 and L7 were selected as promising due to the absence of symptoms and very low viral concentration for both viruses. The resistance genes Ty-1 and Ty-2 were not effective against the viral species used in the study. The lines TY52, H24 and CLN2116B, carrying these genes, exhibited a susceptible behavior.

Integração de dados em estudos de diversidade genética de tomateiro

The objective of this work was to integrate data from quantitative, multicategorical, molecular and phytopathological traits in order to evaluate the genetic diversity of tomato subsamples from the germplasm bank of the Universidade Federal de Vicosa (BGH-UFV). Data from 67 tomato subsamples from BGH-UFV were used, characterized according to 19 quantitative traits, 30 multicategoric characters, 52 ISSR loci, and to the reaction to three diseases (Alternaria solani, Pseudomonas syringae pv. tomato and Tomato yellow spot virus). Initially, the diversity assessment between the subsamples was performed for each set of characters, indicating that diversity based on any one set of data does not reflect the diversity of another set. For the integration of data, the quantitative ones were coded as multicategoric, by five different strategies. The coding strategy with equitable division of the range of data in three classes was the most appropriate, with correlation of 0.78 between the dissimilarity matrices of encoded and original data. The analysis of genetic diversity by the integration of data resulted in groups with higher correspondence to the origins of the subsamples of tomato, indicating that the integration of data from different sources can be successfully carried out by the conversion of quantitative data in multicategoric.

Identificação dos genes Ty-2 e Ty-3 de resistência a begomovírusem genótipos de tomateiro

The objective of this work was to identify the presence of the genes begomovirus resistence Ty-2 and Ty-3 in tomato accessions of the Banco de Germoplasma de Hortalicas of the Universidade Federal de Vicosa. The oligonucleotides TO302 F/R and FLUW25 F/R were used in PCR analysis to verify the presence of markers associated to the genes Ty-2 and Ty-3, respectively. The Ty-2 gene was observed in heterozygosis in the accession BGH-6881 (Solanum peruvianum), and the Ty-3 gene in homozygosis in the accessions BGH-6878, BGH-6897 (S. lycopersicum), and in heterozygosis in acession BGH-6881. The identification of resistance genes, using PCR analysis, represents an advance for tomato breeding programs in Brazil.

Tamanho de coleção original, métodos de agrupamento e amostragem para obtenção de coleção nuclear de germoplasma

The objective of this study was to verify the effect of original germplasm collection size on the effectiveness of different clustering methods and sampling, used to obtain core collections, and to compare these methods in the establishment of core collections. Simulations were made for seven sizes of original collections, and seven sampling strategies were used for the establishment of core collections using morpho-agronomic traits. Eight strategies for obtaining core collections were used, six of them by grouping techniques (Tocher and sequential Tocher), and two without grouping (random and Tocher with inverted criteria grouping). For grouping strategies, constant, logarithmic and proportional sampling were used. The explained variance, the value of the determination coefficient, the coincidence coefficient, and the coincidence standard deviation coefficient between the core and the original collections were determined. The constant and logarithmic sampling strategies generate core collections which are representative of the original collections. The sequential Tocher grouping is more efficient in representing the original collection by the core collection than the Tochers. Among the evaluated strategies the sampling by Tochers inversed grouping criterion is the most efficient to generate representative core collections of the original collections

ANÁLISE DE CRESCIMENTO DO TOMATEIRO EM DIFERENTES SISTEMAS DE CULTIVO

O objetivo do trabalho foi fazer analise de crescimento do tomateiro nos sistemas de cultivo vertical, cerca cruzada e vicosa, visando explicacoes para os ganhos produtivos alcancados no sistema vicosa. O experimento foi conduzido no esquema de parcelas subdivididas, sendo as parcelas representadas pelos sistemas de cultivo: Vertical, tutorado com fitilho em espacamento 1,0 x 0,5 m; Cerca Cruzada, tutorado com bambu em espacamento de 1,0 x 0,5 m; e Vicosa, tutorado com fitilho em espacamento 2,0 x 0,2 m. As subparcelas foram compostas pelas epocas de amostragem das plantas: 15, 30, 45, 60 e 75 dias apos o transplantio (DAT). O delineamento experimental utilizado foi em blocos casualizados, com quatro repeticoes. Cada parcela foi constituida por tres linhas de 10 plantas, perfazendo um total de 30 plantas por parcela, sendo avaliadas as quatro plantas centrais de cada parcela. Avaliou-se materia seca de folhas (MSF), caule (MSC), inflorescencias (MSI), frutos (MSFr) e total (MST), obtidos mediante pesagens diretas de cada orgao da planta. Utilizando-se a area foliar, medida em escâner digital, e as massas secas previamente obtidas foram determinadas as seguintes indices fisiologicos de crescimento: indice de area foliar (IAF), area foliar especifica (AFE), taxa de crescimento relativo (TCR), taxa assimilatoria liquida (TAL). Os dados foram analisados por meio da analise de variância e de regressao. O sistema Vicosa alterou o padrao de crescimento do tomateiro, quantificado pela analise de crescimento, em relacao ao Cerca Cruzada e Vertical. O prolongamento da segunda fase de crescimento para a materia seca de frutos, possivelmente, explicaria os ganhos produtivos obtidos no Sistema Vicosa. Estudos adicionais sao necessarios para esclarecer a relacao entre a duracao da 2 a fase de crescimento da materia seca de frutos, os indices fisiologicos AFE, IAF e TAL com o tamanho e producao de frutos do tomateiro.