Pineapple-‘The King of Fruits’ is one of the commercially important fruit crops of India. It is one of the choicest fruit all over the world because of its pleasant taste and flavor. Pineapple is a good source of vitamin A and B and fairly rich in vitamin C and minerals like calcium, magnesium, potassium and iron. It is also a source of Bromelain, a digestive enzyme. In addition to being eaten fresh, the fruit can also be canned and processed in different forms.
Pineapple (Ananas comosus)
The most popular commercial pineapple variety in India is Giant Kew. Other important verities are Queen, Kew, Mauritius, Charlotte, Rothchild, Jaldhup, Desi, Lakhat, etc.
Qualitatively, Queen is the outstanding table variety used mostly for preparing Juices, concentrates, squashes and pulps.
The ‘Kew’ variety belonging to the Cayenne group is the leading commercial variety. Its properties are considered suitable for canning purposes. ‘Charlotte Rothchild’ is a variety that is partly under cultivation in Kerala and Goa. Fruit characteristics and taste are similar to Kew and Queen.
Areas with a heavy rainfall are best for pineapple growth. Optimum rainfall is 1500mm per year although it can grow in areas having 500mm to 5550mm of rainfall. The fruit grows well near the seacoast as well as in inland, so long as temperature ranges from 15.5 to 32.50 C. Low temperature, bright sunshine and total shade are harmfull. It can grow successfully upto 1525m above sea level.
Pineapple grows in almost any type of soil, provided it is free-draining. Slightly acidic soil with pH range of 5.5 to 6.0 is considered optimum for pineapple cultivation. The soil should be well drained and light in texture. Heavy clay soil is not suitable. It can grow in sandy, alluvial or laterite soil.
Pineapple is a humid tropical plant. It grows well, both in the plains and also at elevations not exceeding 900 metres. It tolerates neither very high temperature nor frost. Pineapple usually flowers from February to April and the fruits are ready from July to September. Sometimes, off-season flowers appear and they produce fruits in September-December.
Propagation and Planting
The choice of planting material is crucial as the performance of the plants developed depends on the materials planted. It is always advisable to use uniform size material of monotype for getting uniform growth of the plants, enabling uniform cultural operations and getting harvest at 1 time from such a field. Hence selection of right type and size of planting material is essential for commercial planting.
Pineapple is commonly propagated from suckers or slips. Suckers arising from the underground parts of the plant are commonly used. Slips arise from the fruiting stem and from the crown on top of the fruit. After the fruit is harvested, stalks are cut into discs and used for propagation. Plants grown from suckers produce fruits in about 18 months, whereas those from slips and suckers propagated from disc cuttings take over two years.
Among the types and sizes of propagules tried, slips and suckers weighing around 350 and 450 g respectively were found best for yield and quality for Kew pineapple. Mass multiplication of propagation material is vital to bring fresh area under cultivation. This is possible only when a number of plantlets can be obtained from a single mother plant, unlike a few suckers or slips. It has been found possible to use leaf cuttings from the crowns of Kew pineapple for multiplication of planting material. Total 10-15 leaf cutting are made from each crown. However, these cuttings will take even more time than crowns for flowering and thus are only recommended where planting material is not available.
Suckers or slips are first cured by stripping off the lower leaves, followed by drying in the sun, or in partial shade for three to four days before planting. They are planted either in flat beds, where there is no danger of water stagnating, or in shallow trenches, which are filled as the suckers grow and develop. Care should be taken to see that they grow and develop. Care should be taken to see that the bud or `heart’ of the suckers does not get buried. A planting density of 43,500 plants per hectare can be followed, keeping a distance of 30 cm between plant and plant, 60 cm between rows and 90 cm between beds. The rainy season is the best time for planting. The system of planting will vary depending on the topography of land and rainfall. There are 4 planting systems in vogue, viz. flat-bed planting, furrow planting, contour planting and trench planting.
The field is prepared by ploughing, harrowing, etc., before planting. In the hills, proper terracing is a necessity. According to the Department of Agricultural Research and Education, ICAR, Government of India, the population density of 44,444 plants/ha with a spacing of 30cm x 60cm x 90cm is best for getting more yield under rainfed conditions.
A dose of N, P2O5 and K2O at 12,4 and 12 g./plant/year respectively is optimum under Jorhat conditions. No response to P application has been observed. However, in the ratoon crop 4 g. P2O5/plant increases fruit weight and yield. Plants receiving 12 g. K2O/plant/crop give higher yield without any adverse effect on fruit quality both under irrigated and rainfed conditions. For medium fertile soils in West Bengal, N (12-16g.), P2O5 (2-4g.) and K2O (10-12 g.)/plant are optimum. It is recommended to apply N and K2O each @ 12g./plant. There is no need for P application. However, if the soils are poor in P, 4g. P2O5/plant can be applied. N should be applied in 6 split doses. The first dose of N can be given two months after planting and the last one 12 months after planting. The K should be applied in two split doses. Entire P and half of K can be given at the time of planting and the remaining K, 6 months after planting. Application of fertilizers under rainfed conditions should be done when moisture is available.
Pineapple is mostly cultivated under rainfed conditions. Supplementary irrigation helps to produce good sized fruits in areas having optimum rainfall. Irrigation also helps to establish an off-season planting to maintain its year round production. In case of scanty rainfall and hot weather, irrigation may be provided once in 20-25 days.
Weeding is done at least three to four times in a year. Hand weeding can be partially eliminated by application of weedicides. Earthing up is an essential operation in pineapple cultivation aimed at good anchorage to the plants. Soon after harvest, earthing up is done leaving one to two suckers only. Weeds are effectively controlled by application of diuron (@ 2 kg./ha.) or a combination of Bromacil and diuron @ 2 kg./ha. each as pre-emergent spray and repeated with half of the dose , 5 months after first application.
Dry leaves or straw is used as a mulching material. Mulching with black polythene and saw dust has been found to be effective. The maturing fruits may be covered with rice straw or pineapple leaves in order to reduce both sun burn and damage caused by the birds.
Application of NAA and related compounds viz. Planofix and Celemone @ 10-20 ppm. induces flowering in pineapple. Application of NAA (200-300 ppm.), two to three months after fruit set increases 15-20% fruit size. To get year round availability of pineapple it should be planned at regular intervals round the year. The application of 50 ml. solution/plant containing calcium carbide (20g./litre) or Ethrel (0.25 ml./l.) causes flower induction.
Removal of suckers, slips and crowns
Suckers start growing with the emergence of inflorescence, whereas slips grow with the developing fruits. The fruit weight increases with increasing number of suckers/plant, while the increased number of slips delays fruit maturity. Crown size has no bearing on the fruit weight or quality. Hence desuckering can be delayed as much as possible, while the slips are recommended to be removed as soon as they attain the size required for planting. Removal of crown is not required as it mars the appeal of the fruit and also makes handling difficult. Partial pinching of crown consisting of the removal of the innermost whorl of leaflets along with growing tips 45 days after fruit set is ideal to get fruits of better size and shape.
Plant Protection Measures
Common Pests and Diseases
Category : Bacterial
Bacterial heart rot and fruit collapse Erwinia chrysanthemi
Remove and destroy infected fruits; avoid the use of infected crowns for seed material to prevent spread of the disease; planting to avoid flowering when adjacent field is fruiting can reduce disease development; use of miticides and control of ants can significantly reduce disease incidence
Category : Fungal
Butt rot, Black rot & White leaf spot Chalara paradoxa
Seed material should be stored on mother plants during dry weather and with good air circulation; freshly removed seed material should be dipped in an appropriate fungicide within 12 hours of removal from the mother plant; avoiding bruising and wounding of fruit during harvest helps to reduce black rot; harvested fruit should be dipped in an appropriate fungicide within 6-12 hours of harvest to prevent disease development during shipping
Category : Other
Marbling (Acetobacter spp. Erwinia herbicola)
There are currently no methods of controlling the disease; the pineapple variety Smooth Cayenne appears to be moderately resistant to the disease
Category : Viral
Mealybug wilt Pineapple wilt virus (PWV)
Ants should be controlled with an appropriate insecticide
Category : Oomycete
Phytophthora heart and root rot Phytophthora spp.
Planting in raised beds helps to drain the soil and reduces incidence of the disease; mulch from pineapple debris should be avoided; pre-planting dips and foliar applications of Fosetyl Al are very effective at controlling the disease
Category : Insects
Mealybugs (Pineapple mealybug) Dysmicoccus brevipes
Mealybugs can potentially be controlled by natural enemies such as lady beetles; ant populations which tend the mealybugs should be treated with an appropriate insecticide
Harvesting and Yield
Pineapple plants flower 12-15 months after planting and the fruits become ready 15-18 months after planting depending upon the variety, time of planting, type and size of plant material used and prevailing temperature during the fruit development. Under natural conditions, pineapple comes to harvest during May-August. The fruit usually ripens about 5 months after flowering. Irregular flowering results in the harvesting spread over a long period. In order to get uniform flowering (over 80%) in the main season, Ethrel (@ 100 ppm.) solution is applied to plants one month before flowering.
The fruits are harvested for canning purpose when there is a slight change at the base of developing fruits. The fruits used for table purpose are retained till they develop golden yellow colour.
The plant crop after harvest can be retained as ratoon crop for three to four years depending upon the soil condition. Ratooning in high density planting reveals that the average fruit weight in the first and second ratoon is 88% and 79% respectively of the plant crop. The plant stand is also reduced gradually resulting in the reduction of fruit yield by 49 and 46% (approx.) in first and second ratoon crops respectively.
The average yield is 50-80 tonnes/ha. depending upon spacing and cultural practices.
POST HARVEST MANAGEMENT
Fruits are graded on the basis of their weight, size and colour.
Fruits with crown can be kept without damage for 10-15 days after harvesting. When fruits are transported to long distances or for a period of several days, refrigerated transport is required to slow down ripening process. Pineapples can be stored well for a period of 20 days when refrigerated at 10-130 C. The best storage is at 7.20 C and 80 or 90% relative humidity.
Fruits are packed in baskets woven with bamboo strips. For local markets, the fruits are arranged in baskets (each weighing 20-25 kg.) lined with paddy straw to stand on their stumps. The second layer of fruits is arranged on the crowns of the first layer of fruits. For distant markets, fruits are wrapped individually with paddy straw and then packed.