Development of globular embryos from the hybridization between 'Pêra Rio' sweet orange and 'Poncã' mandarin

This research was undertaken to study the influence of different concentrations of the MT medium, sucrose, vitamins, activated charcoal and gibberellic acid (GA3) on the culture of immature embryos from the crossing between 'Pêra Rio' sweet orange and 'PONCÃ' mandarin. The embryos were excised under aseptic conditions and inoculated in 15 mL of the MT medium according to the following experiments: 1) MT concentrations (0%, 50%, 100%, 150% and 200%) supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 2) vitamins concentrations of the MT (0%, 50%, 100%, 150% and 200%) supplemented with 0, 30, 60 and 90 g.L-1 of sucrose; 3) activated charcoal concentrations (0, 0.5, 1, 1.5 and 2 g.L-1) supplemented with GA3 (0, 0.01, 0.1; 1 and 10 mg.L-1). After the inoculation, the embryos were kept in a growth room for 90 days at 27 ± 1ºC, in a 16-hour photoperiod with 32 µmol.m-2.s-1 of irradiance. The best development of embryos at the globular stage was achieved using 50% and 100% of the MT medium plus 60 g.L-1 and 90 g.L-1 of sucrose, respectively, supplemented with 0.01 mg.L-1 of GA3. The addition of activated charcoal or vitamins in the MT medium has shown to be unnecessary to the development of globular embryos.

Conservação de uvas "Crimson Seedless" e "Itália", submetidas a diferentes tipos de embalagens e dióxido de enxofre (SO2)

Estudaram-se o efeito de diferentes tipos de embalagens e a ação do dióxido de enxofre (SO2) na conservação pós-colheita de uvas finas de mesa var. "Crimson Seedless" e "Itália". Os frutos, colhidos em propriedade agrícola situada no município de Boa Vista-RR (Lat. 2º 50' 06" N e Long. 60º 40' 28" W), apresentavam, no momento da colheita, sólidos solúveis (SS) médios de 16,50 e 14,80°Brix, para as variedades "Crimson Seedless" e "Itália", respectivamente. Antes da confecção dos tratamentos, os cachos foram higienizados em solução de hipoclorito de sódio (NaOCl) a 100 mg.L-1, previamente acidificada, por dez minutos. Utilizaram-se, para a atmosfera modificada passiva, sacolas de polietileno de baixa densidade (PEBD), sem perfuração, com 0,010; 0,015 e 0,020mm de espessura,e acondicionadas em embalagens secundárias de papelão (4kg) e de madeira (7,5kg). Para a geração do SO2, foram utilizados papéis Kraft de liberação rápida, com 3 e 8g de metabissulfito de sódio (Na2S2O5). Após a confecção dos tratamentos, os frutos foram armazenados em câmara frigorífica a 4 ± 1°C e 95 ± 3% de umidade relativa (U.R.). As avaliações foram realizadas no momento da colheita e, 7; 21; 35; 42 e 56 dias de armazenamento refrigerado, quanto à porcentagem de perda de massa fresca, taxa de desgrana e de bagas deterioradas, qualidade do engaço e teor de SS dos frutos. Após oito semanas, foi realizado teste de preferência para as duas variedades. Verificou-se, em ambas as variedades, que as uvas submetidas à ação do gerador de SO2 , contendo 3g de metabissulfito de sódio e acondicionamento em embalagens de PEBD de 0,020mm de espessura, independentemente do tipo de embalagem secundária, apresentaram a menor perda de massa fresca, menor taxa de desgrana e de bagas deterioradas, e melhor qualidade do engaço. Os resultados da análise sensorial concordaram com os resultados das análises físico-químicas. Não foram detectadas diferenças nos teores de SS entre os tratamentos, em ambas as variedades. (Apoio: Roraima Agrofrutas).

Characterization of sour (Prunus cerasus L.) and sweet cherry (Prunus avium L.) varieties with five isozyme systems

Extracts from young leaves of nine sweet cherry (Prunus avium L.) and eight sour cherry (Prunus cerasus L.) varieties, located in the germplasm collection of the 'Direção Regional de Agricultura da Beira Interior' (Fundão, Portugal), were analysed for five isozyme systems in order to characterise these varieties and detect problems of synonymies and homonymies that frequently present. The sweet and sour cherry varieties analyzed showed low isoenzymatic polymorphism, being PGM and PGI the systems with the highest discrimination power. These systems presented seven and five different zymogrames, respectively. IDH showed four patterns. SKDH and 6-PGD grouped the varieties only into two patterns. The evident and discriminant restrictions of this type of analysis had got results that have only been a complement for agronomical and morphological characterization.

Effect of prestorage curing on storage life, internal and external qualities of sweet orange (Citrus sinensis)

Orange fruits from two seasons, in April and August 2006 representing late 2005 and early 2006 harvests respectively were cured in hot air at 36-37(0)C to 1%, 3%, 5% and 7% weight loss before storage at 28(0)C and 86% relative humidity (RH). The fruits were observed for incidence of decay, further weight loss, juice content, firmness or softening of the peel, total soluble solids (TSS), pH, titratable acidity, and colour during storage. Curing reduced the incidence of decay. All control fruits were rotten by day 21 in August harvest while 22.5% of the control was rotten by day 56 in the April harvest. Storage life was extended beyond 56 days in fruits cured with 1, 3, 5 and 7% in April harvest as there was no decay throughout, while decay incidence in August harvest was 88.9, 61.1, 22.2 and 31.3% in 1, 3, 5 and 7% respectively. Penicillium digitatum, Phytophthora sp., Alternaria citri and Collectotrichum gloeosporioides were among decay causing moulds detected. Control fruits lost more weight during storage than cured fruits did. Fruit rind hardening was more noticed in the control and those cured to 1% weight loss, especially from the April harvest. It was insignificant in other treatments in both trials. Titratable acidity, pH, juice content and TSS were not affected by the treatment. Colour change to yellow was however retarded by curing. Curing to 5% weight loss was best for decay control and quality retention.

Effect of GA3, KNO3, and removing of basal point of seeds on germination of sweet granadilla (Passiflora ligularis Juss) and yellow passion fruit (Passiflora edulis f. flavicarpa)

Passiflora seeds germinate erratically presenting difficulties for their handling in a greenhouse. The effect of removing of basal point of seeds (RB) and pre-imbibition of seeds of sweet granadilla and yellow passion fruit in 50, 100, 200, and 400 mg mL-1 solutions of gibberellic acid (GA3) or 0.1% KNO3 solution was studied. The experiment was conducted in greenhouses in La Plata, Colombia. Two accessions PrJ1 and PrJ2 of sweet granadilla were evaluated. There were calculated the final percentage of germination (PG), mean germination time (MGT), and the mean germination rate (MGR). The leaf area and dry mass of seedlings were measured 22 days after sowing (das); with this data, specific leaf area and relation root/shoot were calculated. In all cases, the highest germination percentages were achieved treating seeds with KNO3 (89, 92, and 87% for yellow passion fruit, PrJ2, and PrJ1, respectively), but the increase in MGR (3.3 germinated seeds per day) and the decrease in MGT (16 days) were only significant for PrJ1. RB had a significant reduction of PG in all cases (28, 12, and 33% for passion fruit, PrJ2 and PrJ1, respectively). With the increase in the concentration of GA3, PG was reduced for two accessions of sweet granadilla, for yellow passion fruit this trend was not clear, no treatment with GA3 showed significant differences with the control. Leaf area (24.07 cm2) and dry mass of seedlings (135 mg) were significantly higher than seeds previously treated with KNO3 only for PrJ1.The solution of KNO3 0,1% is recommended to improve the germination and initial growth of granadilla seedlings.

Antioxidant compoundsand total antioxidant activity in fruits of acerola from cv. Flor Branca, Florida Sweet and BRS 366

Information on antioxidant properties at different ontological stages may help producers and food technologists to identify which cultivar and/or maturity stage are most adequate for their need, therefore this work aimed to study the changes in the antioxidant metabolism during acerola development. Fruit from cv. Flor Branca, BRS366 and Florida Sweet were harvested at different stages: immature green colored (I), physiologically mature with green color and maximum size (II), breaker (III) and full red ripe (IV). After harvest, fruits were selected, divided into four replications with 500 g each and evaluated regarding their titratable acidity, pH, soluble solids, total soluble sugar, vitamin C, polyphenol, anthocyanin, yellow flavonoid, total antioxidant activity and antioxidant enzyme activity. Anthocyanin and flavonoid were determined through LC-DAD-ESI/MS and all analysis followed a completely randomized factorial 3 x 4 design. Fruits of 'Florida Sweet' presented significantly higher soluble solids (9.46ºBrix). Vitamin C content decreased during ripening, but ripe 'BRS 366' fruits showed the greatest values (1363 mg.100 g-1) and highest TAA with 42.36 µM TEAC.g-1FW. Cyanidin 3-rhamnoside (520.76 mg.100 g-1 DM) and quercetin 3-rhamnoside (33.72 mg.100 g-1 DM) were the most abundant anthocyanin and yellow flavonoids found mainly in 'Flor Branca' fruit of acerola, whose antioxidant enzymes activities were also higher. Ripe 'Florida Sweet' fruit presents a great potential for fresh consumption, meanwhile physiologically mature 'BRS 366' fruit seems the best option for the bioactive compounds processing industry. As 'Flor Branca' fruit of acerola kept the highest activity levels, it could be an indicative of greater potential for postharvest conservation.

INFLUÊNCIA DO ÁCIDO GIBERÉLICO NA FISIOLOGIA E QUALIDADE DA VIDEIRA CV SWEET CELEBRATION NO SUBMÉDIO SÃO FRANCISCO

RESUMO O objetivo deste trabalho foi avaliar o efeito da aplicação de doses únicas e fracionadas de ácido giberélico nas trocas gasosas e fotossíntese e na qualidade de cachos da uva cv. Sweet Celebration, no Submédio São Francisco. O delineamento experimental foi o em blocos ao acaso, com 10 tratamentos (testemunha; uma, duas ou três aplicações de 10 mg.L-1; uma, duas ou três aplicações de 15 mg.L-1; uma única aplicação de 20 mg.L-1, de 30 mg.L-1ou de 45 mg.L-1), com quatro repetições, e parcelas constituídas por três plantas. O ácido giberélico, aplicado na fase de bagas com 8 mm, aumentou a massa e as dimensões das uvas, sem influenciar no teor de sólidos solúveis e na acidez titulável. Contudo, maiores massa (9,41 g), comprimento (26,8 mm) e volume (8,12 cm3) de baga foram decorrentes de três aplicações de 10 mg.L-1, resultando em incrementos de, respectivamente, 59%, 23% e 42,5%,quandocomparado à testemunha. As três aplicações de ácido giberélico, nas diferentes fases de desenvolvimento dos cachos, favoreceram a atividade fotossintética e a qualidade do cacho e das bagas.

Analytical investigation of chromium and zinc in sweet, sour and bitter tasting fruits, vegetables and medicinal plants

Sweet, sour and bitter tasting fruits, vegetables and medicinal plants are an important component of human diet. The role of chromium and zinc in carbohydrate metabolism for control of diabetes is highlighted in selected commodities. Average levels of chromium and zinc in sweet taste were 0.69 ± 0.48 mg kg-1 and 4.81 ± 4.31 mg kg-1 respectively with correlation of 0.545, while in sour taste the values were 22.5 ± 22.0 mg kg-1 and 24.5 ± 11.8 mg kg-1 respectively with the correlation of 0.239 and in bitter taste, 0.61 ± 0.33 mg kg-1 and 4.70 ± 3.54 mg kg-1 respectively with correlation of 0.343. Overall, sour tasting commodities were found higher in levels of chromium and zinc and are recommended as food supplement for diabeties. None of these species contain metals above the toxic level.

Natural colonization of leaves of 'Pêra' sweet orange and related varieties by Guignardia citricarpa

The purpose of this research was to evaluate the differences in the colonization and production of structures in the leaves of 'Pêra' sweet orange (Citrus sinensis) clones and related varieties by Guignardia citricarpa. The natural colonization and the production of reproductive structures in the leaves and in vitro of ten 'Pêra' sweet orange was quantified in the following clones: Bianchi, Dibbern C.V., EEL, IAC 2000, Olímpia 15161, Premunizada 1212, Premunizada 1743/82, R. Gullo 1569/244, R. Gullo 1570/246 and Vimusa; and in five related varieties: Redonda C.N, Ovale 968, Ovale San Lio 969, Lamb Summer and Corsa Tardia. The quantification of the colonization density of G. citricarpa in the leaves was obtained through isolation. Incidence and colonization density (cm²) were calculated for each clone. The production of reproductive structures was accomplished through the moistening and drying process of the leaves. The incidence (percentage of affected leaves) and the leaf surface percentage occupied by the reproductive fungus structures were quantified. The in vitro production of reproductive structures was accomplished in water-agar medium. The number of immature and total reproductive fungus structures (cm²), and the percentage of picnidia with liberation of spores were quantified. Significant differences were not observed among clones related to the colonization of the leaves. But there were differences in the induction experiments, i.e., in the leaf surface percentage occupied by the reproductive fungus structures and the in vitro production of reprodutive fungus structures.

Screening of sweet sorghum accessions for inhibition of secondary sporulation and saccharide measurements in honeydew of Claviceps africana

Certain sweet sorghums (Sorghum bicolor) inhibit the secondary sporulation of Claviceps africana, which occurs on exuded ergot honeydew when the parasite is supplied with excess sucrose, which is then transformed to unique free oligosaccharides fructosyl - mannitol and difructosyl - mannitol with spore germination inhibiting properties. Five accessions (BRA-035726-SUGAR DRIP, BRA-035696-THEIS, BRA-036013-MN-4578, BRA-035947-MN-4418 and CMSXS-633) of sweet sorghum were selected among 50 evaluated. These five accessions failed to support secondary sporulation on the "honeydew" exuded from infected florets. There was a higher concentration (%w/v) of the free oligosaccharides on the honeydew of these accessions when compared to a hybrid male-sterile grain sorghum. Therefore, a possible strategy would be seek to incorporate a sweet character into "A" lines for hybrid seed production in order to restrict secondary disease spread.

Effect of temperature, leaf wetness, and rainfall on the production of Guignardia citricarpa ascospores and on back spot severity on sweet orange

The black spot of citrus (Citrus sp.) is caused by Guignardia citricarpa with ascospore production depending on temperature, leaf wetness, and rainfall. The number of ascospores produced was monitored using a spore trap and climatic factors were recorded using an automated meteorological station of 'Natal' and 'Valencia' sweet orange (Citrus sinensis) orchards in Mogi Guaçu in the state of São Paulo, Brazil, from November 2000 to March 2001. The fruits were bagged to prevent infection and the bags removed from different sets of fruit for one week during each of the 18 weeks of the season in both orchards. Ascospores were produced during the entire experimental period, from spring through summer, primarily after rain events. In both orchards, ascospore production reached a peak in January and February. Ascospore production was related to leaf wetness only in the Natal orange orchard but was not related to total rainfall or temperature in either orchard. Disease was most severe on fruit exposed the 7th, 8th, and 13th weeks after beginning the experiment in both cultivars as well as after the 16th week for 'Natal'. There was a strong relationship between disease severity and total rainfall for both orchards and a weak correlation between temperature and severity in the 'Natal' block only. There was no relationship between severity and leaf wetness or ascospore numbers.

Susceptibility of fruits of the 'Valência' and 'Natal' sweet orange varieties to Guignardia citricarpa and the influence of the coexistence of healthy and symptomatic fruits

The importance of the presence of symptomatic fruits with citrus black symptoms (CBS) on the disease severity level in subsequent crop production was assessed in an orchard planted with Valência and Natal sweet orange varieties. Additionally, the period of susceptibility of the fruits of these varieties was evaluated. Fruits were covered with paper bags at the stage of 75% fallen petals and were then exposed to natural infection at weekly intervals, from October 2000 to April 2001. This process was carried out in plants where the fruits from the previous harvest had been picked as well as in plants where fruits remained until natural drop. The evaluation of disease severity used a scale that varied from 0 (absence of symptoms) to 6 (severe symptoms). It was observed that, for the Valência and Natal varieties, conidia of Phyllosticta citricarpa that had formed on the lesions of fruits from the previous harvest did not significantly increase the severity of disease on the fruits of the subsequent harvest period. In this study, the protection of the fruits until 10 weeks after petal drop did not affect the number of lesions, indicating that ascospore discharges after that date were, probably, responsible for disease severity. Fruits exposed between the 20th and 24th week after 75% of the petals had fallen were symptomatic, indicating that, at this stage, the fruits were still susceptible to the pathogen.

Solanum americanum: reservoir for Potato virus Y and Cucumber mosaic virus in sweet pepper crops

Weeds can act as important reservoirs for viruses. Solanum americanum (Black nightshade) is a common weed in Brazil and samples showing mosaic were collected from sweet pepper crops to verify the presence of viruses. One sample showed mixed infection between Cucumber mosaic virus (CMV) and Potato virus Y (PVY) and one sample showed simple infection by PVY. Both virus species were transmitted by plant extract and caused mosaic in tomato (Solanum lycopersicum cv. Santa Clara), sweet pepper (Capsicum annuum cv. Magda), Nicotiana benthamiana and N. tabaccum TNN, and local lesions on Chenopodium quinoa, C. murale and C. amaranticolor. The coat protein sequences for CMV and PVY found in S. americanum are phylogenetically more related to isolates from tomato. We conclude that S. americanum can act as a reservoir for different viruses during and between sweet pepper crop seasons.

Stability of Citrus tristeza virus protective isolate 'Pêra IAC' according to SSCP analysis of old and new lines of three sweet orange varieties

Clonal cleaning, followed by pre-immunization with protective complexes of Citrus tristeza virus(CTV), allowed the commercial cultivation of Pêra sweet orange, a variety that has great importance for Brazilian citriculture but is sensitive to the virus. The use of mild protective isolates in other citrus varieties, even those more tolerant to CTV, can also be of interest to prevent the spread of severe isolates. The aim of this study was to characterize, by means of SSCP (Single Strand Conformational Polymorphism) analysis of the coat protein gene, CTV isolates present in plants of the sweet orange cultivars Pêra, Hamlin and Valencia propagated from four budwood sources: 1) old lines, 2) nucellar lines, 3) shoot-tip-grafted lines, and 4) shoot-tip-grafted lines pre-immunized with the mild CTV protective isolate 'PIAC'. We also evaluated the correlation of the obtained SSCP patterns to stem pitting intensity, tree vigor and fruit yield. SSCP results showed low genetic diversity among the isolates present in different trees of the same variety and same budwood source and, in some cases, in different budwood sources and varieties. Considering tristeza symptoms, lower intensity was noted for plants of new, shoot-tip-grafted and pre-immunized shoot-tip-grafted lines, compared to old lines of the three varieties. The observed SSCP patterns and symptomatology suggested that more severe CTV complexes infect the plants of old lines of all three varieties. The protective complex stability was observed in the SSCP patterns of CTV isolates of some shoot-tip-grafted and pre-immunized clones. It was concluded that the changes detected in other electrophoretic profiles of this treatment did not cause loss of the protective capacity of CTV isolate 'PIAC' inoculated in the pre-immunization.

Biomass allocation and water use efficiency in fertigated sweet pepper

The use of productivity information and efficiency of water use is important for the economic analysis of production and irrigation management, and also helps the economy of water use, which is essential to plant life. The objective of this study was to evaluate the biomass allocation, the water use efficiency and water content in fruits of sweet pepper cropped under the influence of irrigation blades and potassium doses. The statistic design was a completely randomized factorial scheme (5 x 2) and four replications, with five irrigation blades (80; 90; 100; 110 and 120% of crop evapotranspiration) and two levels of potassium (80 and 120 kg K2O ha-1 ), applied according to phenological phase, through a system of drip irrigation with self-compensated drippers, installed in a battery of 40 drainage lysimeters cultivated with sweet pepper (Maximos F1), at Federal Rural University of Pernambuco (UFRPE), Recife, state of Pernambuco, Brazil. The dry biomass production of sweet pepper was influenced by fertigation regimes; when it was set the lowest dose, estimates of the efficiency of water use and moisture in the fruit occurred with the use of irrigation depth of 97 and 95% of ETc, respectively.