Dalmo Lopes de Siqueira

During the spring of 2014, a wide survey was conducted in one of the most important mango (Mangifera indica) cultivating areas located in Minas Gerais State (Brazil) to ascertain the causal agent of severe anthracnose infections and to evaluate disease susceptibility within a world collection of mango germplasm. Overall, 86 cultivars were monitored and 152 fungal isolates recovered from infected samples were identified by morphological characterization, DNA sequencing and phylogenetic analyses. All isolates were identified as Colletotrichum asianum. Under natural disease pressure, it has been possible to ascertain a variable tolerance degree within the germplasm collection. By applying a categorized classification, cultivars were classified as follows: 10 highly sensitive (11.6%), 13 sensitive (15.1%), 18 moderately sensitive (20.9%), 23 moderately tolerant (26.7%), 11 tolerant (12.8%), and 11 highly tolerant (10.4%). The most susceptible cultivars to anthracnose were Ubà, Quinzenga, Amarelinha da Sementeira followed by Aroeira and Correjo, whereas Mallika followed by Ourinho and Lita resulted in the least susceptible cultivars. To the authors’ knowledge, this is the first large-scale evaluation of mango susceptibility to C. asianum infections within a wide number of cultivars. Anthracnose is a serious threat to mango production and assessment of cultivar response to disease could be useful in breeding programs.

The current study aims to evaluate the occurrence and concentration of carotenoids in the pulp and peel of 14 banana and one plantain cultivars in two ripening stages. We analyzed the occurrence and content of lutein, α-carotene, β-carotene, β-cryptoxanthin, and lycopene - by high performance liquid chromatography with UV-visible detection, the content of total carotenoids by spectrophotometry. In the unripe pulp, the ‘Ouro’ cultivar stood out with lutein concentration 13 times higher than that of the ‘Marmelo’. As for α-carotene and β-carotene, ‘Terrinha’ plantain stood out with mean concentration of 1195.30 and 1126.11 μg (100 g MF^-1), respectively. Total carotenoids ranged from 159.66 to 2553.51 μg (100 g MF^-1) in ‘Caipira’ and ‘Terrinha’, respectively. In the ripe pulp there was 36% increase in the lutein content in comparison to the unripe pulp and there was 7.3 and 8.5% reduction in α-carotene and β-carotene levels, respectively. The total carotenoid concentration in the ripe pulp was 17% higher than that found in the unripe pulp. The unripe peel showed lutein predominance, although ‘Terrinha’ stood out with higher α-carotene and β-carotene concentrations than those found in the other cultivars. Lutein concentration hardly changed due to fruit ripening; however, there was slight reduction in α-carotene and β-carotene concentrations.

The rejuvenation pruning or plant prune is a practice used in fruits species such mango tree, whose plants can exceed ten meters heigh, compromising the implementation of practices such as spraying and harvesting. This study aimed to evaluate the resumption of production of adult ‘Ubá’ mango trees, previously pruned and subjected to fertilization with increasing levels of nitrogen over five seasons. The experiment was conducted in Visconde do Rio Branco, MG. Nineteen years old mango trees were pruned and reduced to the primary branches, about 1.5 m above the ground. Excess shoots were removed, remaining five to six branches per tree. In the year in which the plants were pruned, the nitrogen fertilization was initiated with different doses, divided into three equal fractions, between October of one year and February of the following year. Annually were applied per plant, 160 g of P2O5 in the form of simple superphosphate, 350 g of K2O in the form of potassium chloride, according to the results of the soil analysis, and 0, 175, 350, 525 and 700 g of N in the form of urea. Two years after pruning the plants returned to production, and in the first five crops, we quantified the production in kg per plant and the number of fruits per plant. The production of the mango trees was already stable in the fifth crop or seven years after pruning. The dose of nitrogen resulting in the maximum yield was 238.9 g/plant.

There are little information in the scientific literature on flowering and fruiting of ‘Ubá’ mango trees. These information enables to know the proportion of hermaphrodite flowers in inflorescence, fruit set percentage and developmental stages of the fruit. In this study evaluations on inflorescence and fruit development of the ‘Ubá’ mango tree (Mangifera indica L.) were carried out, as well as the determination of the required number of heat units for full fruit development. Thirty branches whose terminal buds were swollen were selected from five mango trees. With the aid of a camera and a caliper, the panicle and fruit development were evaluated weekly until full fruit development. A digital thermometer was used to record ambient temperatures during fruit development in order to estimate the number of heat units required for complete development of the fruits. Male and hermaphrodite flowers of the panicles were also identified and counted. The developmental cycle of ‘Ubá’ mango from the beginning of apical bud swelling to commercial harvest of the fruit lasted 168 days in 2011 and 154 days in 2012. The number of hermaphrodite flowers and the percentage of fruit set in the inflorescence in 2011 were 32.3 and 0.066%, respectively; and 122.1 and 0.099% in 2012, respectively. There was accumulation of 3,173 heat units from flower bud swelling to full development of the ‘Ubá’ mangoes.

The occurrence of water stress in mango trees grown in orchards located in semi-arid climates in Brazil is frequent. Water stress caused to plants may predispose them to the incidence of fungal diseases. The aim of this study was to evaluate the effect of water deficit on the incidence and severity of Ceratocystis wilt in mango trees considered resistant. Seedlings of ‘Ubá’ and ‘Dura’ were kept in pots and submitted to different water stress levels and inoculated with Ceratocystis fimbriata isolate (CEBS15). Mortality was low in ‘Ubá’ plants and high in ‘Dura’ plants. ‘Ubá’ plants showed lower severity and lesion length. In ‘Ubá’ plants, water deficit influenced the increase in lesion length. ‘Dura’ plants showed greater severity and lesion length, which were not affected by increasing water stress. It was concluded that ‘Ubá’ variety is resistant to fungus Ceratocystis fimbriata, even in severe drought conditions, while ‘Dura’ variety was not resistant to CEBS15 isolate, even under optimum irrigation conditions.

The aim of this study was to evaluate the response of mango plants ( L) ‘Mangifera indicaTommy Atkins’ cultivar to different NaCl concentrations. In this experiment, plants were grown in pots with washed sand and nutrient solution with 0, 10, 20 and 30 mM NaCl for 120 days. After this period, young leaves from the last growth spurt were harvested in a randomized block design, dried at 65 °C for 72 h and ground in a ball mill. Samples were dried again in an oven at 60 °C for 24 h and then the relative abundance of 13C and 12C isotopes was determined using mass spectrometer Sercon 20-20 isotope ratio model. Data were used to determine the carbon isotopic discrimination (?). It was concluded that ‘Tommy Atkins’ mango trees submitted to 30 mmol L-1 NaCl discriminated less 13C, which may be an indication of salt stress in these plants.

The 'Ubá' mango tree cultivar is very important for the juice industry in the "Zona da Mata" region of the Minas Gerais State, in Brazil, but problems such as uneven flowering and low yield have discouraged producers. This study aimed at evaluating the effect of paclobutrazol, combined with branch tip pruning, on the flowering induction and quality of 'Ubá' mango tree fruits. Treatments were distributed in a 5 x 2 + 1 factorial arrangement, consisting of five paclobutrazol doses (0 g, 0.50 g, 1.00 g, 1.50 g and 2.0 g per linear meter of canopy), with and without branch tip pruning, in a randomized blocks design, with four replicates. The flowering percentage, number of panicles per branch, total flowers per panicle, male/hermaphrodite flowers ratio, number of fruits per branch and fruit quality were evaluated. Plants treated with tip pruning showed a higher flowering percentage. There was an increase in the flowering percentage in response to the paclobutrazol dose, reaching a maximum level at the dose of 1.62 g per linear meter of canopy. Plants submitted to branch tip pruning had a higher number of panicles per branch. There was an increase in the male/hermaphrodite flowers ratio with increasing paclobutrazol doses. Branch tip pruning increased the number of fruits per branch. There were no differences in fruit quality in response to the paclobutrazol application. It was concluded that the paclobutrazol application at the dose of 1.62 g per linear meter of canopy, combined with branch tip pruning, increases the flowering of the 'Ubá' mango tree and does not change the fruit quality.

The objective of this work was to morphologically characterize 15 banana cultivars and assess the physical and chemical characteristics of their fruits at two maturation stages, unripe (pre-climacteric) and ripening. The plants were evaluated regarding their pseudostem height and diameter, petiole length, leaf blade length, width and length-to-width ratio. The cultivar Ouro had fruits with lower diameter, total length, market weight and fresh weight at both stages, and also firmer pulp when they were unripe. The cultivar Caru-Roxa had higher fresh fruit and pulp weights, and the cultivar Terrinha had the highest percentage of pulp dry weight percentage in unripe and ripe fruits. The cultivars Maçã and Ouro had higher pulp-to-peel ratio in unripe fruits. The ripe peels had lower fresh weight and thickness and higher dry weight percentage compared to unripe peels. The fruit peel of the cultivar Marmelo had the highest fresh weight at both stages. The cultivars Marmelo and Maçã had higher percentage of peel dry weight percentage at both stages. The unripe pulp had lower soluble solids. The titratable acidity in the pulp increased with ripening. The average plant height ranged from 2.25 to 6.15 m. The cultivars that had the largest pseudostem diameters had also the highest heights, except the Prata-Anã and Prata-Graúda. The cultivar and maturity stage influenced all the characteristics evaluated in fruits, except the total and market lengths, which did not vary with the ripening of fruits.

The aim of this work was to evaluate the effect of passive modified atmosphere packaging (MAP) on the maintenance of fruit quality during the extended storage of ‘Rocha’ and ‘Packham’s Triumph’ pears. Fruit were packed in linear low density polyethylene (100 mm), with 6% BIF 1500 additive placed into perforated plastic boxes and kept at 0 ± 1 °C and 90 ± 5% RH for up to 180 days. MAP reduced weight loss by 14.8% for ‘Rocha’ and 11.5% for ‘Packham’s’ pears after 180 days in cold storage and retained the green color of the skin, which means that the yellowing visual perception was delayed in 60 and 90 days for ‘Rocha’ and ‘Packham’s’ pears, respectively. A strong softening was observed for ‘Packham’s’ pears after being kept for 150 days at 0° C followed by 5 days at room temperature, which did not limit the storage of both pear cultivars under modified atmosphere packaging. MAP created by linear low density polyethylene (100 mm), with 6% BIF 1500 additive extended in 30 days the cold storage for ‘Rocha’ and 60 days for ‘Packham’s’ pears.

The aim of this study was to evaluate 12 rootstock varieties on the development and quality of ‘Tahiti’ acid lime fruits cultivated in the municipality of Jaíba, MG. Seedlings were planted in an experimental orchard in November 2008, using 8 x 5 meters spacing and drip irrigation. The experiment was conducted using a scion cultivar (Tahiti acid lime, IAC-5 cultivar) and the following 12 rootstocks: ‘Rangpur’ lime, ‘Troyer’ citrange, ‘Carrizo’ citrange, 1707 hybrid (Rangpur lime x Swingle trifoliate), 1710 and 1697 citrandarins, 1708citradia, ‘Swingle’ citrumelo, ‘Cleopatra’ and ‘Sunki’ mandarins, ‘Volkamer’ lemon, and ‘Limeira’ trifoliate. A randomized block design with five replicates and three trees per plot was used. Trunk diameter of both rootstock and scion, as well as height, diameter, and canopy volume, yield, fruit mass, number of fruits per tree, productivity, production efficiency index, longitudinal diameter, equatorial diameter, total soluble solids, total acidity, and vitamin C content of fruits were evaluated. ‘Volkameriano’ and ‘Cleopatra’ rootstocks promoted higher plant vigor and productivity for ‘Tahiti’ acid lime. However, ‘Limeira’ trifoliate and ‘Troyer’ citrange produced less vigor, but increased production efficiency; and can be used as alternative rootstocks for ‘Rangpur’ lime, as long as adjustments are performed in the planting spacing to increase productivity. In general, no differences in physical and chemical characteristics of fruits for all treatments were found, and fruits remained within commercial standards.