New species of Rhinoleucophenga, a potential predator of pineapple mealybugs

The objective of this work was to describe a new species of Rhinoleucophenga (Diptera: Drosophilidae). Rhinoleucophenga capixabensis sp. nov. is described based on specimens collected from pineapple (Ananas comosus var. comosus) infested with Dysmicoccus brevipes (Hemiptera: Pseudococcidae) in the state of Espírito Santo, Brazil. Distinguishing characters of R. capixabensis sp. nov. include hyaline wings, a strong seta on the second antennal segment, body length of about 2-3 mm, uniformly dark brown scutellum, one pair of strong prescutellar setae, ventral epandrial lobes with about 17-18 teeth, and female cerci with approximately 20 long setae.

Optimization of a protocol for the micropropagation of pineapple

The present work aimed at maximizing the number of plantlets obtained by the micropropagation of pineapple (Ananas comosus (L.) Merrill) cv. Pérola. Changes in benzylaminopurine (BAP) concentration, type of medium (liquid or solidified) and the type of explant in the proliferation phase were evaluated. Slips were used as the explant source, which consisted of axillary buds obtained after careful excision of the leaves. A Sterilization was done in the hood with ethanol (70%), for three minutes, followed by calcium hypochlorite (2%), for fifteen minutes, and three washes in sterile water. The explants were introduced in MS medium supplemented with 2mg L-1 BAP and maintained in a growth room at a 16h photoperiod (40 mmol.m-2.s-1), 27 ± 2ºC. After eight weeks, cultures were subcultured for multiplication in MS medium. The following treatments were tested: liquid x solidified medium with different BAP concentrations (0.0, 1.5 or 3.0 mg L-1), and the longitudinal cut, or not, of the shoot bud used as explant. The results showed that liquid medium supplemented with BAP at 1.5 mg L-1, associated with the longitudinal sectioning of the shoot bud used as explant presented the best results, maximizing shoot proliferation. On average, the best treatment would allow for an estimated production of 161,080 plantlets by the micropropagation of the axillary buds of one plant with eight slips and ten buds/slips, within a period of eight months.

Management of slips and its effect on growth and production of 'Pérola' pineapple plants

The lack of good quality planting material has limited the expansion and contributed to yield reduction of the Brazilian pineapple culture. Alternatives of 'Pérola' pineapple slips management were studied aiming at obtaining superior planting material within a shorter time period and making good use of healthy slips of low vigor, that are commonly discarded by growers. Two experiments were carried out at the Experimental Field of Embrapa Cassava & Fruits, Cruz das Almas, Bahia, Brazil, and another one in a commercial plantation in the region of Itaberaba, BA, using blocks or entirely randomized designs with at least four replications. In the first one, the development of slips of different initial sizes (6 to 20 cm long), when grown on mother plants after fruit harvest, was compared with that of slips grown in a nursery after their removal from the mother plants. It became clear that larger slips grow more vigorously and that the removal from the mother plant delays their growth. However, results from the second study showed that those slips grown in nursery had vegetative and agronomic performance similar to that of conventional slips and close to that of plantlets produced from plant stem sections. Independently from the type of planting material used, the larger ones presented a more vigorous growth and produced higher yields. In the third study, it was observed the influence of mineral fertilization, pest control and growth regulator application after fruit harvest on slip development. The treatments applied did not significantly accelerate slip growth. Slips reached 50 cm length and at least 300 g fresh weight within 90 days after fruit harvest, indicating that vigorous plants have enough nutritional storage material for slips development.

Pineapple yield and fruit quality effected by NPK fertilization in a tropical soil

There is a lack of information about fertilization of pineapple grown in the State of São Paulo, Brazil. So a field experiment with pineapple 'Smooth Cayenne' was carried out to study the effects of NPK rates on yield and fruit quality. The trial was located on an Alfisol in the central part of the State of São Paulo (Agudos county). The experimental design was an incomplete NPK factorial, with 32 treatments set up in two blocks. The P was applied only at planting, at the rates of 0; 80; 160 and 320 kg/ha of P2 0(5), as superphosphate. The N and K2O rates were 0; 175; 350, and 700 kg/ha, applied as urea and potassium chloride, respectively, divided in four applications during the growth period. Response functions were adjusted to yield or to fruit characteristics in order to estimate the nutrient rates required to reach maximum values. The results showed quadratic effects of N and K on yield and a maximum of 72 t/ha of fresh fruit was attained with rates of 498 and 394 kg/ha, respectively of N and K2O. In order to reach the maximum fruit size, and to improve the percentage of first class fruit (mass greater than 2.6 kg), were necessary rates of N and K respectively 11 and 43 % higher than those for maximum yield. No effect of P rates was observed on pineapple plant growth, despite the low availability of this nutrient in the soil. The effect of N rates was negative on total soluble solids and total acidity while the opposite occurred with K, which increased also the content of vitamin C. High yield and fruit size were closely related to N and K concentrations in the leaves.

Residual effect of growth regulators in etiolation and regeneration of in vitro pineapple plants

This work aimed to evaluate the influence of naphthaleneacetic acid (NAA) and gibberellic acid (GA3) plant regulators in in vitro etiolation and subsequent regeneration of the PE x SC-60 pineapple hybrid. Nodal segments of in vitro plants with approximately 5-7 cm height were incubated in basic MS culture medium supplemented with 0.0; 0.5 and 1.0 mg L-1 of naphthaleneacetic acid (NAA) in combination with gibberellic acid (GA3) in concentrations of 0.0; 0.5 and 1.0 mg L-1, and maintained at 27 ºC under dark condition. Evaluations were carried out at 90 and 180 days after incubation period. The best results for length of etiolated stems were obtained with 1.0 mg L-1 of NAA. In the experiment followed by the regeneration, stems with 3 cm from the etiolation treatment, were cultivated in proliferation medium and the number of regenerated plants per treatment was evaluated at 60 days of cultivation. The treatment that promoted the best etiolation of plants also promoted the worst regeneration rates, demonstrating the residual effect of the auxin used in the previous step in the regeneration of plants of the pineapple hybrid evaluated.

Potassium fertilization for pineapple: effects on plant growth and fruit yield

A field experiment with pineapple (Smooth Cayenne) was carried out on an Ultisol located in the city of Agudos (22º30'S; 49º03'W), in the state of São Paulo, Brazil, with the objective of investigating the effects of rates and sources of potassium fertilizer on plant growth and fruit yield. The experiment was a complete factorial design (4x3) with four rates (0, 175, 350, and 700 kg ha-1 of K2O) and three combinations of K sources (100% KCl, 100% K2SO4, and 40% K2SO4 + 60% KCl). Plant growth and fruit yield were evaluated. Biomass accumulation of pineapple plants was impaired by chlorine added with potassium chloride. Fruit yield increased with potassium fertilization. At high rates of K application, fertilization with K2SO4 showed better results than with KCl. Detrimental effects of KCl were associated with excess of chlorine.

Potassium fertilization for pineapple: effects on soil chemical properties and plant nutrition

A field experiment was carried out on an Ultisol located at the city of Agudos (22º30'S; 49º03'W), in the state of São Paulo, Brazil, in order to determine the effects of rates and sources of potassium fertilizer on nutritional status of 'Smooth Cayenne' pineapple and on some soil chemical properties. The experiment was a complete factorial design with four rates (0, 175, 350, and 700 kg ha-1 of K2O) and three combinations of K sources (100% KCl, 100% K2SO4 and 40% K2SO4 + 60% KCl). Soil samples were taken from the depths 0-20 cm, 20-40 cm and 40-60 cm at planting and 14 months after. Nutritional status of pineapple plants was assessed by means of tissue analysis. Soil K availability increased with application of K fertilizer, regardless of K sources. Soil chlorine and Cl concentration in pineapple leaves increased with application of KCl or K2SO4+KCl. Plant uptake of potassium was shaped by soil K availability and by the application rates of K fertilizer, independently of K sources.

Growth, production and quality of pineapple in response to herbicide use

In pineapple fields, weed competition is exacerbated by the fact that the crop is small and has a very slow vegetative development. The objective of this study was to determine the effects of herbicides on growth, yield and quality of pineapple, cultivar 'Pérola'. The experimental design was in randomized blocks with four treatments and four replications. Treatments consisted of weeding by hoe and the herbicides diuron; fluazifop-p-butyl and atrazine + S-metolachlor applied in post-emergence. The characteristics evaluated monthly during the vegetative stage were stem diameter, D-leaf length, number of leaves, number of emitted leaves and percentage of natural floral induction. In the reproductive phase, evaluations were made of average fruit weight (g) with and without crown, fruits length and diameter, number of slip, slip-sucker and sucker type seedlings, determination of soluble solids and pH in the pulp. There was no effect of herbicide treatment on the vegetative growth characteristics. Stem diameter increased until 330 days after planting, showing a decrease after this period. The D-leaf grew over time in all treatments, although phytotoxicity symptoms were observed after the first application of herbicides. The traits evaluated on the reproductive phase showed no significant differences in response to treatments. Therefore, the use of diuron fluazifop-p-butyl and atrazine + S-metolachlor did not affect growth, yield and fruit quality of pineapple, cultivar 'Pérola'.

Growth and production of irrigated vitória pineapple grown in semi-arid conditions

This study aimed to evaluate the growth characteristics of irrigated Vitória pineapple plants grown in semi-arid conditions and determine its developmental stages based on those characteristics. It was used a randomized block design with four replicates. The experimental treatments were: plant harvest at 270, 330, 390, 450, 510, 570, 690, 750, and 810 days after planting (DAP). The following variables were determined: plant height, stem diameter, D-leaf length, D-leaf fresh and dry mass, biomass production of plants and plant parts (organs), and vegetative biomass. Five phenological stages are proposed based on vegetative biomass production: < 20% biomass production (V1); 21-40% (V2); 41-60% (V3); 61-80% (V4); and > 80% (V5). The maximum growth rate for plant height, D-leaf length, and stem diameter was observed at the end of the phenological stage V1 (390-411 DAP), and at the end of stage V5 these plant traits had average values of 106, 82, and 7 cm, respectively. The maximum biomass accumulation rates were observed at stages V4 and V5, resulting in a final fruit yield and total fresh biomass of 72 t ha-1 and 326 t ha-1, respectively. Finally, we estimated that 80% of the accumulated biomass may remain in the field after fruit and slip harvest, and could be incorporated as plant residue into the soil.

Pineapple (Ananas comosus) cv. pérola ex vitro growth and mycorrhizal colonization affected by in vitro sucrose concentration

The aim of this study was to evaluate the effect of sucrose concentration in the culture medium on growth and on the establishment of mycorrhizas during the acclimatization of pineapple cv. Pérola. The plantlets were micropropagated in MS culture medium with 0, 10, 20 and 30 g L-1 of sucrose and then they were acclimatized during 12 weeks under greenhouse conditions, in a sandy soil - compost mixture, uninoculated or inoculated with a Rhizophagus clarus isolate. Plantlets from the culture medium with 20 g and 30 g of sucrose L-1 showed higher shoot and root biomass than those from sugar-free medium. Mycorrhizal colonization was lower in plantlets micropropagated in sucrose-free medium, but the intensity of arbuscules did not differ among treatments. In the 12-week period of acclimatization, mycorrhizal colonization had no effect on plant biomass.

Influence of depectinization in the ultrafiltration of West Indian cherry (Malpighia glabra L.) and pineapple (Ananas comosus (L.) Meer) juices

West Indian cherry (Malpighia glabra L.) and pineapple (Ananas comosus (L.) Meer)juice clarification by cross-flow UF, using polysulphone hollow fiber and ceramic tubular membranes with, respectively, nominal molecular weight cut off values of 100kDaltons and average pore diameters of 0.01mm, were studied. The influence of enzymatic treatment using enzyme concentrations of 20, 100 and 300mg/L, a time of 90min and a temperature of 40ºC for depectinization was verified. The juices were then clarified in a laboratory scale filtration unit, with an effective filtration area of 0.12m² for the polysulphone hollow fiber membrane and of 0.005m² for the ceramic tubular membranes. The influence of enzymatic treatment on viscosity, turbidity and total pectin of the juice, before ultrafiltration, is reported. Membrane performance was evaluated in terms of flow rate and clarity of the permeate. The permeate flow rate of depectinized pineapple juice was higher (30 - 60%) for both membranes. Depectinized West Indian cherry juice presented a lower permeate flow rate for the polysulphone hollow fiber membrane. The increase in permeate flow rate, with the use of the 300mg/L and 100mg/L enzyme concentration was not significant, so it is economically advantageous to ultrafilter depectinized juice, treated with an enzyme concentration of 20mg/L.

Quality evaluation of fresh-cut ‘Pérola’ pineapple stored in controlled atmosphere

The purpose of this research was to determine the best gas mixture in controlled atmosphere conditions to store fresh-cut ‘Pérola’ pineapple, particularly in relation to the maintenance of visual quality and reduction of microbial growth. After sanitation, fruit was manually peeled, sliced and dipped in 20 mg.L-1 NaOCl solution for 30 seconds. Then, the excess liquid was drained and the slices were placed in sealed glass jars connected to a flowboard installed in a cold room (5 ± 1 °C). Desired gas mixtures were supplied continuously for 12 days from cylinders connected to the flowboard. Controlled atmospheres of 2:5, 2:10, 2:15, 5:5, 5:10, 5:15, 8:5, 8:10 and 8:15 (O2:CO2, %) and air were used. The product was evaluated for pulp color, total and fecal coliforms, mesophilic and psychrotrophic aerobic, mold and yeast counts. Total and fecal coliforms were not detected. The fresh-cut ‘Pérola’ pineapple was not very sensitive to storage in controlled atmosphere, considering that the slices had little browning and were free of contamination, that would affect the food safety at the end of the storage period

Carbohydrate composition of ripe pineapple (cv. perola) and the glycemic response in humans

Brazil is the third largest producer of pineapple (Ananas comosus) and the market for fresh pineapple is sustained by the Hawaii and Perola cultivars. In this work the Perola cultivar was divided into three main parts, shell, core and pulp, for characterization. Moisture in the pulp was higher (between 10 and 15%) than in the shell and core. The amount of protein was higher in the core (35%) than in the pulp and shell. Perola contained relatively low concentrations of total ascorbic acid in the edible parts, although higher levels of ascorbic acid in the shell. Citric acid corresponded to almost 60% of the total organic acids. The total soluble sugars [~7-12% (FW)] were predominantly sucrose, fructose and glucose. The core had almost twice as much total sugar (12%) than the pulp (6.8%). The amount of insoluble dietary fiber was around 1%, and the soluble fiber was less than 0.1%. The pulp showed the highest concentration of polyphenols (0.49%) and antioxidant activity (33 µmol.g-1) out of the parts. The consumption of the pineapple pulp or core produced a high glycemic index (~93%), but considering the glycemic load, this fruit can be considered as low dietary.

Clarification of pineapple juice by microfiltration

In the present work, pineapple juice was first hydrolyzed with a commercial pectinase (Ultrazym 100 G) and then clarified by microfiltration. A tubular polyethersulfone membrane with an average cut-off of 0.3 µm and a total effective filtration area of 0.05 m² was applied. The transmembrane pressures were 1.5 and 3.0 bar, respectively, and the processes was conducted at room temperature. The results showed that the pineapple juice permeate fluxes were of 57.77 L/m²/hours (1.5 bar) and 46.85 L/m²/hours (3.0 bar). Concentration polarization and possibly fouling occurred during the processes. The best clarified juice fluxes were obtained when low transmembrane pressures (1.5 bar) were applied.