Rosana Gonçalves Pires Matias

Curva de crescimento e padrão respiratório de frutos de genótipos de pessegueiro em região de clima subtropical

O trabalho teve como objetivos determinar a duracao do ciclo e caracterizar as fases da curva e o padrao respiratorio dos frutos de genotipos de pessego cultivado em regiao de clima subtropical. O experimento foi conduzido no Pomar experimental da Universidade Federal de Vicosa (UFV), em Araponga-MG. Foram selecionados dez genotipos provenientes do programa de melhoramento genetico da UFV onde, quinzenalmente, foram colhidos 50 frutos, desde a antese ate o completo amadurecimento. As amostragens ocorreram de junho a novembro de 2011 e foram avaliados diâmetros (polar, equatorial e sutural), massa de materia fresca e seca (fruto, casca, polpa e caroco) e a producao de CO2. O padrao de crescimento foi sigmoidal duplo, sendo o intervalo entre a antese e a colheita de 135 dias para os genotipos 803-10; 803-33; 803-55;1.603-51 e 5.503-25, o que permitiu classifica-los como de ciclo medio e de 180 dias para os genotipos 2.903-1; 5.003-46; 8.503-6; 9.103-1 e 9.903-2, o que os caracterizou como de ciclo longo. O crescimento dos frutos avaliados apresentou tres estagios de crescimento: estagio I, com crescimento exponencial; estagio II, com pouco crescimento, e estagio III, novamente com crescimento exponencial, culminando com a maturacao do fruto. A producao de CO2 diminuiu ao longo do tempo com presenca de picos em determinadas epocas. No final do ciclo, foram observados os picos climatericos. O final do climaterio marcou o comeco da senescencia do fruto, o que coincidiu com seu completo amadurecimento na planta.

Correlação entre características quantitativas e qualitativas de frutos de pessegueiros na geração F2 cultivados em região subtropical

O objetivo deste trabalho foi avaliar as relacoes entre caracteristicas quantitativas e qualitativas de frutos de pessegueiro, cultivados em regiao subtropical. Para isso foram utilizados frutos totalmente maduros, obtidos de cinco populacoes, em geracao F2, cultivadas em condicoes de clima subtropical. Foram avaliados: coloracao da epiderme (coordenadas b* e h°), diâmetro medio do fruto, comprimento do fruto, firmeza instrumental da polpa, teor de solidos soluveis, acidez titulavel, teor de acido ascorbico, percentagem de vermelho na epiderme, coloracao da polpa, aderencia do caroco, consistencia manual da polpa e epoca de colheita. Os dados foram utilizados para obtencao de coeficientes parciais de correlacao entre todas as variaveis. Observou-se variacao entre os valores obtidos para cada caracteristica. Ha correlacoes parciais significativas a 1% de probabilidade, de intensidades medias e fracas, entre as caracteristicas estudadas de frutos de pessegueiro. As maiores correlacoes foram obtidas entre comprimento e diâmetro de frutos (0,690**) e entre os descritores b e h, obtidos por meio de colorimetro (0,516**). Frutos mais tardios apresentam, geralmente, maior firmeza de polpa, menores teores de vitamina C e menos pigmentacao amarela na epiderme. Pessegos de polpa amarela sao mais firmes e apresentam maior acidez no suco.

Caracterização de acessos de mangueira Ubá na Zona da Mata Mineira

Objetivou-se realizar a caracterizacao fisica e quimica de acessos de manga Uba na regiao da Zona da Mata de Minas Gerais, visando a identificar materiais de interesse industrial. Frutos fisiologicamente maduros foram colhidos e transportados para o Laboratorio de Analise de Frutas da UFV, onde foram lavados, tratados com fungicida Prochloraz (Sportak 450 CE, Hoeschst Schering AgrEvo UK Ltd., Inglaterra), na dose de 49,5g100L-1 de agua, por 10 minutos e secos ao ar. Em seguida, foram tratados com Ethephon, acido 2-cloroetil fosfonico, (Ethrel 240g de ethephon.L-1, RHone-Poulenc Agro Brasil LTDA) na concentracao de 1g i.a.L-1 juntamente com espalhante adesivo Adesil (760g i L-1, Nufarm Industria Quimica e Farmaceutica S.A.) na concentracao de 20mL 100L-1 durante 5 minutos e secos ao ar. Em seguida, foram armazenados a 20±1°C e umidade relativa de 90% e avaliados apos o completo amadurecimento. Os frutos que apresentaram melhores caracteristicas para o processamento industrial foram os provenientes dos acessos 7, 11, 16, 17, 21, 26, 28, 47, 48, 53, 54 e 56. A massa de fruto, firmeza, teor de solidos soluveis e teor de acido ascorbico sao as caracteristicas que apresentaram maior variabilidade dos acessos de mangueira Uba. A variabilidade genetica existente nas mangueiras Uba, em Visconde do Rio Branco propicia disponibilizar materiais para futuros trabalhos de melhoramento genetico e implantacao de banco de germoplasma.

Diversidade genética entre cultivares de mangueiras, baseada em caracteres de qualidade dos frutos

Genetic diversity among cultivars of mango based on fruit quality traits The mango crop is one of the most significant agribusiness in Brazil. Although there are many cultivars, cultivation has been done primarily with ‘Tommy Atkins’ and there are few studies on characterization and analysis of genetic diversity in different areas of production. Therefore, the objective of this work was to study the genetic diversity of fifteen mango cultivars, eight from Brazil and seven from Florida (USA), produced in the Zona da Mata Mineira region. Fifteen ripe fruits from each cultivar were collected and analyzed chemically and physically . The cultivars that showed more similarities were ‘Kent’ and ‘Palmer’. ‘Extrema’ was not grouped with the others by the UPGMA clustering method. This analysis was also used for the separation of Brazilian and USA cultivars. The principal component analysis of the chemical characteristics did not group the cultivars ‘Extrema’ and ‘Tommy Atkins’ with the others. The physical characteristics showed the same separation obtained by the UPGMA method, except for the cultivar ‘Extrema’ that was grouped with other cultivars. There was correlation between the color of the pulp, hue angle, and total soluble sugar content and between the color of the peel, b* index and percentage of peel and pulp.

Seleção de genótipos de pessegueiro com base na necessidade de frio para germinação das sementes

The peach is a temperate species that presents dormancy, and the exposure to a period at low temperatures is the main method to overcome it. This work consisted in studying the chilling requirement for germination of peach seeds. To assess the germination the seeds were stratified at alternating temperatures of 5oC and 10oC every 2 days and observed in order to verify the onset of radicle emission. The time (days) required for seeds to reach 50% germination was determined. A completely randomized design was used, with four replications, each experimental unit consisting of 10 seeds. The families selected according to the characteristic studied were 2303, 4203, 4503 and 5303, considering the selection among and within, whereas the families 2303, 3503, 4203, 4503 and 5303, considering the combined selection. Families studied presented adaptation to the environmental conditions of cultivation, especially concerning the climate, critical to the success of the crop.

Cold storage of peaches cv. Aurora grown in the Zona da Mata Mineira, Minas Gerais State, Brazil

This study aimed to evaluate the postharvest behavior of peach cv. Aurora 1 harvested in the Zona da Mata region of Minas Gerais in two ripening stages and kept under different storage temperatures. Fruits on mid-ripe and fully ripe stages were stored at three temperatures: 5.6 ± 1.57 °C and 72.8 ± 3.8% RH; 10.4 ± 0.5 °C and 95.8 ± 5.5% RH; 21.04 ± 1.63 °C and 96.9 ± 2.6% RH up to 28 storage days (SD) . During storage, fruits stored at 21.04 ± 1.63 °C were evaluated every two days until 8 SD, and every four days for fruits stored at other temperatures. The harvest day was assigned as day zero. The variables evaluated were CO 2 production, color of the pericarp and pulp, fresh mass loss, flesh firmness, total soluble solids, titratable acidity , contents of ascorbic acid and carotenoids. The fresh mass loss increased during storage, peaking at 5.6 °C. The reduction in ascorbic acid content was higher in fully ripe fruits at all temperatures. Midripe fruits reached the end of the storage period with better quality . The temperature of 10.4 °C was the most efficient in keeping postharvest quality of peach cv. Aurora 1 harvested in the Zona da Mata region.

REPETIBILIDADE DE CARACTERES DE FRUTO EM PESSEGUEIRO

O objetivo deste trabalho foi estimar os coeficientes de repetibilidade em cultivares de pessegueiro e nectarineira e predizer o numero de medicoes necessarias para asprincipais caracteristicas de fruto. Em tres ciclos, avaliaram-se quatorze caracteristicas quimicas e fisicas de frutos. Para a estimativa dos coeficientes de repetibilidade, do numero de medicoes necessarias e do coeficiente de determinacao, foi utilizado o metodo da analise de variância (ANOVA). Determinou-se, para cada caracteristica, o numero minimo de medicoes, para predizer o valor real das cultivares. Observou-se variabilidade genetica entre os genotipos. As estimativas de repetibilidade foram elevadas, o que mostra a regularidade das cultivares. Para predizer o valor real dos caracteres de fruto com confiabilidade acima de 80%, sao necessarios a realizacao de medicoes em quatro frutos e quatro anos de avaliacao.

Repeatability, correlation and path analysis of physical and chemical characteristics of peach fruits

This study aimed to determine the number of measurements necessary to evaluate physical and chemical characteristics of peach fruits, study the relationships between them and their direct and indirect effects on the content of ascorbic acid and total carotenoids. The characteristics skin and pulp color, fruit weight, suture, equatorial and polar diameters, firmness, soluble solids (SS), titratable acidity (TA), SS/TA ratio, ascorbic acid and total carotenoids were evaluated in 39 cultivars of peach and 3 cultivars of nectarine from the orchard of the Universidade Federal de Vicosa. The repeatability coefficient was estimated by ANOVA and CPCOR. Phenotypic correlation coefficients (rf) were estimated and, after the multicollinearity diagnostics, they were unfolded to direct and indirect effects of the explanatory variables on the response variable using path analysis. There was agreement on the magnitude of repeatability coefficients obtained by the two methods; however, they varied among the 14 characteristics. The highest correlations were found between FW, SD, ED and PD. Seven fruits are sufficient to evaluate the physical and chemical characteristics of peach with a correlation coefficient of 90%. The characteristics considered in the path diagrams (b* skin, ho skin, b* pulp, ho pulp, ED, PD, FIR, SS, SS/AT and TC) are not the main determinants of the ascorbic acid. The yellow hue of the pulp (ho pulp) has the potential to be used in indirect selection for total carotenoids.

TRATAMENTO HIDROTÉRMICO PARA PREVENÇÃO DO ESCURECIMENTO DO PERICARPO DE LICHIA

The browning of litchi pericarp (Litchi chinensis Sonn.) occurs rapidly after harvest, limiting the marketing period of the fruits. The objective of this study was to evaluate the effect of hot water treatments in preventing browning of the pericarp and the maintenance of postharvest quality of litchi fruit. Fruits of litchi cv. Bengal uniformly red pericarp were submitted to immersion in water at tree temperature (45, 50 and 55°C) x five soaking times (0, 4, 8, 12 and 16 minutes) in a completely randomized design with tree replications and five fruit per replicate. After drying, the fruits were packed in polystyrene trays, covered with plastic wrap with 12 mm thick and stored in the lab benches at room temperature (19.0 ± 2.4°C and 75 ± 5% RH) to simulate the exposure conditions at supermarket counters. Every two days, during eight days, were evaluated the weight loss, color of the pericarp, soluble solids, titratable acidity of the pulp and ascorbic acid content of the pericarp and pulp. It was observed that the weight loss was higher in fruits that were not subjected to hydrothermal treatment. Fruits subjected to 50°C during 16 minutes and 55°C in all immersion times were evaluated only until the 4th day, thereafter, these fruits are not suitable for commercialization. Immersion at 45°C during four minutes was the most effective in maintaining the red color of the pericarp and did not affect the quality measured during the experimental period.