Cayenne Pineapple Research Articles

Quality optimisation of combined osmotic dehydration and microwave assisted air drying of pineapple using constant power emission

Combination of osmotic dehydration with microwave assisted air drying offers increased flexibility for process control and product quality. Osmotic dehydration (55°Brix solution at 40°C for 90min) combined with microwave assisted air drying (MWAD) was tested on smooth cayenne pineapples. The influence of the four most relevant processing parameters (osmotic treatment time, microwave power, air temperature and air velocity) was studied using a 24 circumscribed central composite experimental design. The product quality was evaluated in terms of charred appearance at the surface, moisture content, soluble solids content, water activity, firmness, colour and volume. Microwave power and air temperature were the two most important processing parameters that influenced the quality of the dehydrated pineapple, with the parameters most affected by the operating conditions being water content and percentage of charred pieces. Only in the latter was a significant quadratic effect found, all others were approximately linear. There was also a significant interactive effect between microwave power and air temperature affecting the percentage of charred pieces. Model predictions using a quadratic surface for water content and % charred pieces were validated with an additional experiment. Quadratic models were used to indicate optimum drying conditions for various targets.

Effects of sulphiting and osmotic pre-treatments on the effective moisture diffusion coefficients D<sub>EFF</sub> of air drying of pineapple slices

Air dehydration of fruits has been reported to be limiting in some factors especially on the drying kinetics and quality of the dried fruits. Removal of moisture during drying is attributed to these. This study was designed to evaluate the effects of sulphiting and osmotic pretreatments on effective diffusion coefficient (Deff) of air drying pineapple slices at 50o and 70 oC temperatures. Smooth cayenne pineapple obtained from Ajanla farms, Ibadan, Nigeria was used for the study. The fruits were hand peeled and sliced to spherical slices of 5 cm radius and 0.5 cm thickness. Pineapplefruit slices were pretreated at three levels of sulphiting and sucrose/osmosis and two conditions of drying (50 oC at 16 h and 70 oC at 10 h), resulting in 18 treatments in a factorial experimental design. Changes in moisture were monitored hourly and Fick’s second law was used to describe the rate of moisture transfer to determine the Deff as the slices were dried using a cabinet dryer. Results showed that the Deff was strongly affected by sulphiting at 2500 ppm equalling 9.10+ 0.13 x 10-6 and 6.78 + 0.53 x 10-6cm/s for 70 oC and 50 oC drying temperatures, respectively. The osmotic pretreatment at 40% sucrose recorded 4.91 + 0.15 x 10-6cm/s and 6.93 + 0.03 x 10-6cm/s for 70 oC and 50 oC drying temperature respectively. The control samples had 3.14 + 0.23 x 10-6 and 4.19 + 0.21 x 10-6 at 70 oC and 50 oC drying temperature, respectively. The high values obtained from the pretreated samples may be due to the restructuring of the cell walls. The combination of sulphiting and osmotic pretreatments also exhibited significant impact on the Deff value, ranging between 5.13 to 8.42 x 10-6, though not as pronounced as with the single pretreatment method. Furthermore, drying at 70 oC influenced the Deff value more than drying at 50 oC with both pretreatment methods. The study, therefore, showed that pretreatment methods improved the Deff of the pineapple slices, with the sulphiting pretreatment at 2500 ppm having the highest value.Key words: Sulphiting, osmotic, pretreatment, drying, kinetics

Air-Oven Drying of Pre-Treated Fruit Slices: A Promising Solution to Post-Harvest Losses

Reports have shown that over 25% of fruit are lost during their season and virtually out of the market during off season due to their high moisture content couple with poor preservation methods practiced in Nigeria. Smooth cayenne pineapple specie obtained from Ajanla Farms, Ibadan was used for the study. A two factor-factorial experimental design of 3-levels of 3 pre-treatment methods (sucrose, blanching and sulphiting) and 3-levels of drying conditions (80 C/8 h, 70 C/10 h and 50 C/16 h) resulting into 81 treatments o o o was used. The treatments were reduced to 18 by stratified sampling method from the results of the moisture and ascorbic acid content obtained from the pre-treated slices before drying. The slices were dried in a cabinet dryer; the moisture and ascorbic acid content of the dried slices were monitored during drying and after. All the samples exhibited combinations of falling and increase in drying with increasing in drying time. The dried slices were stored for 18 weeks, at which they were analyzed at 3 week intervals. The results obtained revealed that there were significant effects (p<0.05) of the pre-treatments on the ascorbic acid and moisture content of the dried slices. The 60%S/60 CB/2500ppm SO at 70 C/10 h had the least value of o o 2 moisture content of 8.75% and 25.16 mg/100 g of ascorbic acid. Furthermore, the results indicated that drying at 70 C/10 h is suitable for drying of pineapple slices than other drying conditions. During storage, o there was continuous reduction in moisture content during the early weeks of storage. However, after 9 weeks of storage the moisture content of the samples increased showing significant differences between the mean values of the samples at different weeks of storage. Though, the samples pretreated with SO2 showed a little variation over the storage period. Drying condition of 70 C/10 h and pre-treatment of 2500 ppm o SO /60% sucrose was found to have minimal reduction of quality and thus the most appropriate treatment 2 for air-oven drying of pineapple slices. The study therefore, recommends that production of pre-treated dried fruit slices could be used to reduce the enormous post-harvest losses of fruits.

Extração, atividade da bromelina e análise de alguns parâmetros químicos em cultivares de abacaxi

Diante dos riscos e das limitações advindos do cultivo exclusivo de abacaxizeiros Pérola e Smooth Cayenne e visando à variabilidade genética, o Estado da Paraíba estuda material genético diversificado: os híbridos Emepa-01, Imperial e MD-2. objetivando a caracterização destes novos híbridos, avaliaram-se alguns parâmetros químicos e a atividade da bromelina nas polpas e nas cascas de todas as cultivares. o abacaxi Smooth Cayenne apresentou o menor pH (3,44 para polpa e 3,91 para a casca) e a maior acidez titulável (0,56g de ácido cítrico para 100g de polpa e 0,52g de ácido cítrico para 100g de casca), sendo a cultivar mais ácida. Dentre as polpas, as dos abacaxis Pérola e Smooth Cayenne contiveram níveis de açúcares redutores, não redutores e totais significativamente maiores (p&lt;0,05) do que os híbridos, apesar de estes terem valores mais elevados (maior que 30,00) da relação sólidos solúveis e acidez titulável e, consequentemente, maior aceitação pelo consumidor. o extrato bruto da cultivar Imperial apresentou maior atividade proteolítica e teor de proteína tanto na polpa (56,41 U/ml e 7,50 mg de proteína/ml) quanto na casca (68,56 U/ml e 10,40 mg de proteína/mL). Para a atividade específica, a casca do abacaxi Pérola (10,01 U/mg de proteína) contém valor significativamente mais elevado que os encontrados nas demais amostras. No entanto, dentre as polpas, a da cultivar Imperial (7,49 U/mg de proteína) apresenta atividade específica significativamente superior (p&lt;0,05) às demais.

Leaf reddening disease of pineapple in Ghana

A disease of pineapple, which threatens production of the exportable Smooth Cayenne pineapple, is reported. The disease has been observed in several commercial plantings in the Akwapim South, Ga and Gomoa districts, respectively, in the Eastern, Greater Accra and Central regions of Ghana. Reddening of the leaves (often interspersed with diffuse, irregular chlorotic patches), leaf dieback and plastic-like leaf consistency are the major above-ground symptoms. Diseased plants have reduced root systems, but internal browning of the underground stem is absent, indicating non-involvement of vascular wilt organisms, which have so far not been isolated from such plants. Mealybugs and ants are sometimes, but not always, associated with diseased plants. Nematodes of the genera Pratylenchus, Aphelenchus and Helicotylenchus have been recovered, though infrequently, from roots and root zone soil of diseased plants. Based on these preliminary results and field observations, it is hypothesized that the new disease of pineapple in Ghana could be of complex etiology with nematodes perhaps constituting one major group of primary causal agents and stress factors (e.g. soil moisture stress, low soil fertility and weed competition) being either primary agents or pre-disposing factors. Ongoing studies seek to conclusively determine the etiology of the disease as well as some factors affecting its epidemiological development. Until this is done, it is proposed that the disease be simply referred to as “red leaf disease” of pineapple after its dominant and most readily recognized symptom. Control measures for the disease are much needed if production of pineapple for export is to be sustained. To the author’s knowledge, this is the first-published, detailed account of a disease of this nature in Ghana.

Effect of Explants Density on the in vitro Proliferation and Growth of Separated and Cluster Shoots of Smooth Cayenne Pineapple (Ananas comosus L. Merr.)

Multiplication rate was always used as the sole parameter for assessment of the optimal treatment for in vitro shoot formation. However, beside its effect on the shoot formation, different treatments had different impact on the production cost. Separated shoots and shoot cluster of different sizes (1, 2, 3 and 4 shoots per cluster) of Smooth cayenne pineapple were cultured at density of 1, 2, 3 and 4 separated shoots and 1 cluster on agar solidified full strength MS medium enriched with sucrose at 30 g L-1 and BAP at 2.25 mg L-1 for 2 months to investigate the effect of explants density and explant types on shoot formation per explant, total per liter and cost per shoot. Density of one separated shoot per culture resulted in the highest shoot formations per shoot (11 shoots) but lowest total shoot per liter (550 shoots) and highest cost per shoot (13 cents), while density of 4 shoots per culture resulted in lowest rate (4 shoots) but higher total per liter (1400 shoots) and lowest cost per shoot (10 cents). Cluster of two shoots had higher rate (7 shoots) and lower cost (16 cents) than cluster of 4 shoots (4 shoots and 20 cents) but both resulted in equal total shoot per liter (750 shoots). Separated shoot had higher shoot formation capacity, higher total per liter and lower cost per shoots than cluster of shoots and using of total per liter instead of rate per explant was the best parameter for selection of treatment of lower cost and higher shoots production. © 2009 Asian Network for Scientific Information.

Protease inhibitors and reproduction of reniform nematode in pineapple

AbstractEndogenous protease inhibitors (PIs) in the roots of Smooth Cayenne pineapple clones may affect the growth of the plant‐parasitic nematode Rotylenchulus reniformis. In pineapple, reniform population densities remain atypically near preplant levels for 6–9 months after pineapple planting. A potted plant experiment was conducted to determine if the PI present in pineapple roots affected nematode reproduction and possibly account for the observed nematode field population dynamics. Pineapple PI activity increased for the first 6 months after planting and was higher in nematode‐inoculated plants. Nematode reproduction, however, was not correlated to PI activity. In a second experiment, PI activity was concentrated in the portion of the roots nearest the pineapple butt where nematode population densities were highest. The behaviour of the PI in pineapple roots suggested a defensive role, such as systemic acquired resistance, against R. reniformis.

Effect of Benzylaminopurine (BAP) on in vitro Proliferation and Growth of Pineapple (Ananas comosus L. Merr.) cv. Smooth Cayenne

The effect of 6-benzylaminopurine (BAP) at concentration range of 0 to 3.75 mg L-1 applied at concentration difference of a fixed increment of 0.25 mg L-1 on the in vitro shoot formation and average and total of shoot length and weight per explant of smooth cayenne pineapple were evaluated. BAP significantly affected the average of shoot number, length and weight but did not affect the total length and total weight per explant. The maximum shoot formation (12 shoots/explant) occurred at 4 concentrations of BAP (1.75, 2.0, 2.25 and 3.5 mg L-1) while tallest (25 mm) and heaviest (0.60 g) shoots obtained on MS hormone free medium. Shoot formation pattern showed two sudden increases in shoot formation. The first occurred at 1.25 and second at 3.50 mg L-1 and two sharp declines at 2.5 and 3.75 mg L-1. Identifying of the concentrations with contrasting effect where an increase and decline in the shoot formation pattern occur provide an essential base from which an informative successful histological and biochemical studies could be designed to elucidate shoot formation mechanism. © 2008 Asian Network for Scientific Information.

The Effect of Different Hormones and Incubation Periods on in vitro Proliferation of Pineapple (Ananas comosus L.) Merr cv. Smooth Cayenne) Shoot-Tip Culture

Seven different hormone treatments, namely 6-benzylaminopurine (BAP) at 2, 3 mg L(-1) was applied singly and in combination with Indole Acetic Acid (IAA) at 0.18, 0.8 and 1.8 mg L(-l), BAP at 3.3 mg L(-l) in combination with IAA at 1.8 and 3.3 mg L(-l) and triple combination of BAP at 2.3, IAA at 1.8 and Gibberellic acid (GA3) at 1.0 mg L(-1) were tested, over four different incubation periods of 30, 45, 60 and 75 days, for their effect in the proliferation and growth of Smooth cayenne pineapple shoot-tip culture. Combined application of BAP at 3.3 and IAA at 1.8 mg L(-1) induced the highest proliferation of 19 shoots/explant and the highest total of 121 and 125 shoots over 4 cycles of multiplication. Raising the IAA to 3.3 mg L(-1) resulted in the lowest proliferation and stunted shoots. Incorporation of GA3 improved the shoot length but caused drastic reduction in proliferation. The other treatments showed an intermediate effect.

COMPARATIVE CONSUMER AND PHYSICOCHEMICAL ANALYSIS OF DEL MONTE HAWAI`I GOLD AND SMOOTH CAYENNE PINEAPPLE CULTIVARS

ABSTRACT Del Monte Hawai`i Gold (Del Monte Fresh Produce [Hawai`i], Inc., Honolulu, HI), an experimental hybrid clone of Smooth Cayenne pineapple, was found to have significantly higher (P &lt; 0.0001) pH, °Brix/acid ratio, yellow color, total carotenoid content and vitamin C than Smooth Cayenne, while the titratable acidity of Smooth Cayenne was significantly higher (P &lt; 0.0001). Hawai`i consumers also significantly liked and preferred Del Monte Hawai`i Gold more than Smooth Cayenne pineapples when presented in three different forms: whole, unpeeled pineapple, pineapple spears and single‐strength juice. Results suggest that Del Monte Hawai`i Gold can surpass Smooth Cayenne as the market standard for fresh pineapples and for single‐strength pineapple juice.

HORTICULTURAL CROP QUALITY CHARACTERISTICS IMPORTANT IN INTERNATIONAL TRADE

Significant increases have occurred in the volume and value of horticultural crops involved in international trade. Many lesser-developed countries have prioritized high-valued non-traditional crops (i.e. fruits, vegetables, and floricultural crops) as an integral part of their nationwide economic development plan. Buyers and consumers in the principal importing nations require consistent supplies of high quality products. Proper external and internal quality characteristics must be met, which may vary depending on the market destination. Color, texture, size, and flavor continue to be the predominant quality characteristics important for successful international marketing of horticultural crops. Product nutraceutical value is also a quality characteristic playing a significantly more important role among consumers in making purchasing decisions. Significant shifts in fruit and vegetable crop demand have recently occurred based on product quality characteristics. Examples include the shift in demand from Smooth Cayenne pineapple to the sweeter, more attractively colored MD-2 cultivar, easy-peel seedless citrus fruit, high skin blush low fiber mangoes, higher internal colored papayas and grapefruit, uniquely-flavored apples, high antioxidant containing berries, sweet onions, and fresh-cut pre-packaged shelf-ready fruits and vegetables. Innovations in product presentation and convenience will continue to play a significant role in export marketing of horticultural crops. New and unique product colors, flavors, and textures will continue to attract consumer interest and create international market opportunities.

Transformation and regeneration of pineapple

We have developed efficient methods for plant regeneration, via both organogenesis and embryogenesis, of Smooth Cayenne pineapple, Ananas comosus (L.) Merr. A range of different types of embryogenic tissues has been developed with varying properties in terms of growth rate and state of development (Firoozabady and Moy, 2004). Two of the embryogenic systems, namely friable embryogenic cell clusters (ECCs) and chunky non-dispersible embryogenic tissues (ETs) have been used for transformation of pineapple. The tissues were cocultivated for 2???3 days with Agrobacterium tumefaciens disarmed strain C58 carrying a binary vector containing either surB gene conferring resistance to chlorsulfuron or the nptII gene conferring resistance to geneticin (G418). After cocultivation and a recovery period, tissues were selected on media containing chlorsulfuron or G418. On average, about 50 or 120 independent transgenic lines were obtained from each gram of ECCs or ETs, respectively, inoculated with Agrobacterium. Transformed embryogenic tissues were transferred to maturation media to form somatic embryos, which subsequently produced transgenic pineapple plants. Transformation has been confirmed by GUS assay, polymerase chain reaction, and by Southern hybridization. Thousands of plants from independently transformed lines were transferred to the greenhouse and to the field to evaluate clonal fidelity and somaclonal variation.

HYDROGEN PEROXIDE AND ASCORBIC ACID CONTENTS, SUPEROXIDE DISMUTASE AND CATALASE ACTIVITIES IN SMOOTH CAYENNE AND QUEEN PINEAPPLES DURING COLD STORAGE

Pineapples (Annanus comosus L. Murr.) could easily develop chilling injury symptom during storage at low temperature, depending on maturity, cultivar, temperature and duration of storage. Queen pineapples are known to more sensitive to chilling injury than other groups. Low temperature is believed to cause oxidative stress in plant tissues leading to chilling injury symptoms. Queen and Smooth Cayenne pineapples were stored at 10°C for 3 weeks. Queen pineapples developed slight internal browning after only one week of storage and more than 50% showed moderate symptom after 3 weeks. There was no symptom in Smooth Cayenne after 3 weeks of storage. Hydrogen peroxide content in the flesh of Queen was higher than in Smooth Cayenne before and during storage. Ascorbic acid content was also higher in Queen. Superoxide dismutase activity in Smooth Cayenne was higher at the beginning but declined to about the same level as in Queen. Catalase activity in Queen before storage was three times higher than that in Smooth Cayenne. After one week of storage the activity declined considerably. The higher sensitivity to low temperature in Queen as compare to Smooth Cayenne may be explained by the higher H 2 O 2 content, but further study on other antioxidants and enzymes involved are needed.

Regeneration of pineapple plants via somatic embryogenesis and organogenesis

We have developed efficient methods for plant regeneration, via both embryogenesis and organogenesis, of Smooth Cayenne pineapple, Ananas comosus (L.) Merr. Leaf bases and core (stem) sections of in vitro shoots, produced from culture of crown tip meristem, were used as explants for plant regeneration as follows: (1) Leaf base and core section explants cultured on Murashige and Skoog (MS) medium containing 41 μM 4-amino-3,5,6-trichloropicolinic acid (picloram, P) or thidiazuron (T)/P combinations produced embryogenic tissues. Different types of embryogenic tissues (friable emryogenic tissue, embryogenic cell cluster, and chunky embryogenic tissue) have been developed with varying properties in terms of growth rate and state of development. The embryogenic tissues regenerated shoots upon culture on MS medium containing 13 μM 6-benzylaminopurine (BA) and 1μM α-naphthaleneacetic acid (NAA) followed by culture on MS medium containing 4 μM BA. (2) Crown tip meristems cultured on MS medium containing 13 μM BA followed by leaf explants cultured on MS medium with 27 μM NAA and 1 μM BA produced shoots via direct organogenesis. (3) Explants cultured on MS medium containing 5 μM T and 0.5 μM indole-3-butyric acid (IBA) produced nodular globular structures, which produced shoots upon culture on MS medium containing 1 μM BA and 1 μM gibberellic acid. Shoots obtained from all of the above methods were rooted in half-strength MS medium containing 3 μM NAA and 2.5 μM IBA. Plants were transferred to the greenhouse or shipped to Costa Rica for field trials. Somatic embryo-derived plants exhibited 21 % spininess, and organogenic-derived plants exhibited 5% spininess in the field trials.

Cost-effective in vitro propagation methods for pineapple.

We have developed an efficient and cost-effective method for commercial micropropagation of Smooth Cayenne pineapple. In vitro shoots were used as starting materials, and either longitudinal sections of the shoots or leaf bases were used as the explants to regenerate shoots. When these explants were used, the axillary meristems, which usually remain quiescent during shoot multiplication, were able to form new shoots. Subsequent to the regeneration step, additional multiplication was achieved inside a 10-l Nalgene vessel with shoots immersed in liquid medium for 5-10 min/h (periodic immersion bioreactor, PIB). The shoots were then induced to form roots and transferred to soil. Using the above micropropagation method and the PIB, we produced 6,000-8,000 shoots from two initial shoots in less than 6 months. The clonal fidelity of propagated plants was tested in Costa Rican and Indonesian pineapple farms.

Pérola and Smooth Cayenne pineapple cultivars in the state of Bahia, Brazil: growth, flowering, pests, diseases, yield and fruit quality aspects

Introduction. Perola, the most important cultivar in Brazil and almost unknown in other countries, and Smooth Cayenne, the most grown cultivar in the world, belong to different pineapple groups with distinct botanical, morphological and agronomic characteristics. The principal characteristics and behavior of the cv. Perola pineapple were analyzed, in comparison with the cv. Smooth Cayenne ones. Materials and methods. A comparison between Perola and Smooth Cayenne was done, based upon results and observations made in studies carried out by Embrapa in Brazil, during the past 20 years. Results and discussion. The cv. Perola plant usually has a smaller stem than the cv. Smooth Cayenne with a lower number of roots and leaves, but the `D' leaves are longer, wider and more erect. The peduncle is longer, holding a narrower, longer, cone-shaped fruit, with a whitish, less fibrous flesh and edible central core, lower acidity and higher [(total soluble solids) / (titrable acidity)] ratio and juice content. The cv. Perola is more sensitive than the cv. Smooth Cayenne to natural and artificial flowering induction, but it is less susceptible to the wilt disease transmitted by mealy bugs and to the stem borer (Castnia icarus ). Cv. Perola produces many slips, but suckers appear later, are less uniform and less well-fixed to the mother plants, making it more difficult to get a good first ratoon crop. Conclusions. The yield potential of the cv. Perola is lower than that of the cv. Smooth Cayenne, due to a lighter fruit and usually lower planting density used. Its production costs are also lower, especially due to cheaper planting materials and a lower number of pesticide applications. The overall performance of the cv. Perola plants and fruits explains the wide use of this variety in Brazil and its potential use in other countries.

ALTAS DENSIDADES DE PLANTIO NA CULTURA DO ABACAXI CV. SMOOTH CAYENNE, SOB CONDIÇÕES DE SEQUEIRO

No Brasil têm-se usado densidades de plantio relativamente baixas para a obtenção de frutos grandes, com reflexos negativos na produtividade da cultura do abacaxi. No entanto, frutos cada vez menores têm sido comercializados no mercado internacional, o que poderá também ocorrer no mercado nacional. Este trabalho teve o objetivo de avaliar o efeito de altas densidades em sistemas de plantio em filas duplas sobre a produção quantitativa e qualitativa de abacaxi cv. Smooth Cayenne, sob condições de sequeiro. Densidades de plantio, variando de 51.280 plantas/ha a 100.000 plantas/ha, foram estudadas em delineamento experimental de blocos casualizados, com cinco repetições e doze tratamentos, distribuídos em esquema fatorial 4 x 3, correspondendo a quatro combinações de espaçamentos entre linhas duplas e entre linhas simples na fila dupla (90cm x 40 cm, 90 cm x 30 cm, 80 cm x 30 cm , 70 cm x 30 cm) e três espaçamentos entre plantas nas linhas de plantio (30 cm, 25 cm, 20 cm). A análise de variância determinou diferença estatística apenas para a produtividade, em função do espaçamento entre plantas na linha de plantio, sendo mais elevada para o espaçamento de 20 cm. O peso do fruto, as suas dimensões e a sua qualidade (açucares, acidez, teor de suco, relação açúcares/acidez) não foram significativamente influenciados pelas densidades de plantio estudadas, mantendo-se dentro dos padrões da cultivar. Para cada aumento de 10.000 plantas por hectare, a produtividade cresceu em 8,27 t/ha e o peso médio do fruto caiu 102 g. Nas condições ambientais dos Tabuleiros Costeiros do Norte da Bahia, a cultura do abacaxi cv. Smooth Cayenne apresenta potencial para uso em altas densidades de plantio, mesmo em cultivo de sequeiro, podendo-se atingir produtividade acima de 80t/ha e peso médio do fruto superior a 1,0 kg.

Nitrogen and potassium requirement of pineapple in relation to irrigation in Nigeria

The investigation studied the effect of fertilization with four nitrogen levels (0, 100, 150 and 200 kg/ha), four potassium levels (0, 100, 150 and 200 kg/ha) and four irrigation treatments (0, 3, 7 and 14-day interval) on the growth and yield of smooth Cayenne pineapples. Increasing irrigation frequency increased growth parameters of number of leaves, D-leaf length and days to 50% flowering. Fruit weight was highest at N = 150 kg/ha, K = 200 kg/ ha and irrigation once a week. Higher N levels (beyond 150 kg/ha) applied after the plant crop has been harvested did not further enhance yields of the ratoon crop. For K = 200 kg/ha potential and harvested yields were reduced in all irrigation treatments when N > 150 kg/ha.

Fertilizer rates for increased pineapple production in the tropical ferrallitic soils of South Western Nigeria

The investigation studied the optimal fertilizer rates and mixtures for maximum production of smooth cayenne pineapples in the tropical ferrallitic soil.

Estudo sobre o ciclo natural do abacaxizeiro 'Cayenne' no planalto paulista

Com o objetivo de obter subsídios para o escalonamento racional das épocas de produção de abacaxi 'Cayenne' no planalto paulista, foi realizado um experimento de campo sobre o ciclo natural da planta em função de plantios trimestrais de mudas dos tipos coroa, filhote e rebentão de 300 a 400g, bem como do tipo rebentão de 700 a 800g. Constatou-se a existência de dois grandes períodos de diferenciação floral espontânea: o principal, em abril-maio (meados de outono), e o secundário, em novembro-dezembro (entre meados da primavera e inicio do verão). Os resultados obtidos serviram de base para a elaboração de um quadro indicativo das melhores mudas e das respectivas melhores épocas de plantio e indução química da diferenciação floral para diferentes épocas de produção desejadas, sem uso de irrigação.