Propagation
The performance of the plant depends on vigour,
growth rate, time taken for bearing, fruit size and quality of planting
material. Besides type and size of plant material also results in variation in
the performance of plants. If planting material of different types and
sizes is used, it results in poor rate of plant establishment, uneven growth of
the plants, uneven flowering and harvesting stretched over a long time. Uniform
cultural operations cannot be taken up. Ultimately plant-wise operations are to
be followed resulting in increased cost of production. In a mixed planting, a
few plants flower while others become ready for harvesting, posing problems for
getting good uniform ratoon crops also. Therefore, it is always advisable to
use uniform-sized material of monotype. Hence, selection of right type and size
of planting material is essential for commercial plantings.
In suckers and slips, larger planting material
results in more vigorous plants. Of the types and sizes of propagules tried,
slips and suckers weighing about 350 and 450g respectively are ideal for higher
yield with better produce. For Coorg (Karnataka) and Jorhat (Assam) suckers and
slips weighing 501–750g and 301–400g are ideal planting material. Suckers
weighing 501–1000g is the best material for Thrissur (Kerala). In case of
non-availability of slips, suckers weighing about 500g are ideal. If sufficient
suckers are not available, slips weighing about 350g are best.
CULTIVATION PRACTICES
Planting
Time of planting is dictated by the season in
which the first plant crop is required. Planting time is very important for
natural flowering period, which differs from region-to-region. By the time
of natural flowering, if the plant does not attain the optimum
physiological maturity, either it escapes flowering the next season or if
flowering is induced in the same season, the plant, bear very small fruits.
Hence, the ideal time of planting is 12–15 months before the peak flowering
season under natural conditions, which varies from December to March in
different regions. Time of planting also varies from place-to-place depending
upon the time of onset of the monsoon and the intensity of its precipitation.
In Assam, planting should be done during August–October, while in Kerala and
Karnataka, the best time of planting is April–June. Delaying in planting as
late as September, delays crop at least by 7–9 months. The peak flowering under
these conditions comes during January–March. The ideal time for planting in
north West Bengal is October–November and June–July for other parts.
System of planting varies according to land and
rainfall. There are 4 planting systems flat-bed, furrow, contour and trench.
Plant density of pineapple depends on growth of
the plant and system of planting. Adoption of low-planting densities has been
the major constraint in India, contributing to high cost of production. The
plant density of 63,400 plants/ha (22.5cm × 60cm × 75cm) is ideal for
subtropical and mild humid conditions, whereas for hot and humid conditions a
plant density of 53,300 plants/ha spaced at 25cm from plant-to-plant within a
row, 60cm from row-to-row and 90cm from trench-to-trench (25cm × 60cm × 90cm)
provides high yield. In rainfed, high fertile and hilly areas in north-eastern
states, a plant density of 43,500 plants/ha spaced at 30cm × 60cm × 90cm is
recommended. The yield of 70–105 tonnes/ha may be obtained under high-density
planting, the increase in yield/unit area being 45–85 tonnes/ha. Adoption of
high-density planting does not have much adverse effect on fruit size, quality
and canning recovery. Less weed infestation, protection of fruits from
sun-burn, increased production of propagules (suckers and slips)/unit area and
non-lodging of plants are added advantages of high-density planting.
Manuring and fertilization
Pineapple is a shallow feeder with high N and K
requirement. Since these nutrients are prone to heavy losses in soils,
practices relating to time of application and form of fertilizer determine
their efficient use.
Application of 12g N/plant for Kew pineapple is
ideal to obtain high yield at Bangalore, Chethalli (Karnataka) and Thrissur
(Kerala). A dose of N, P2O5 and K2O
at 12, 4 and 12g/plant/year respectively is optimum under Jorhat conditions. No
response to P application has been observed. However, in the ratoon crop 4g 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 (10–12g)/plant
are optimum.
It is thus advisable 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. The N should be applied in 6 split doses. The first dose of N
can be given 2 months after planting and the last one 12 months after planting.
The K should be given in 2 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 fertilizer under rainfed conditions should be done when moisture is
available.
Interculture
Earthing up:
This is an essential
operation in pineapple cultivation aimed at good anchorage to the plants. It
involves pushing the soil into the trench from the ridge where trench planting
is a common practice. As its roots are very shallow, the plants are eventually
lodged especially under flat-bed planting in heavy rainfall areas. Lodging
of plants at the time of fruit development results in lopsided growth, uneven
development and ripening of fruits. It is more important in ratoon crop as the
base of ratoon plants shifts up, crop after crop. High-density
planting minimizes its necessity as the plants prop each other preventing
lodging.
Weed control:
Weeds could be effectively
and economically controlled by application of Diuron (3 kg/ha) or a combination
of Bromacil + Diuron @ 2kg/ha each as pre-emergent spray and repeated with half
of the dose, 5 months after first application. The quantity of each herbicide
should be mixed in 1,000 litres of water for a hectare of crop.
Mulching:
It is essential to conserve soil
moisture. Though mulching is not a common practice in India, use of dry leaves
or straw is in practice in south India. Mulching with black polythene and
saw-dust results in better growth of plants than white polythene and
paddy-straw.
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 delay 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.
Irrigation
Although pineapple is cultivated mostly under
rainfed conditions, supplementary irrigation can help produce good-sized fruits
in areas having optimum rainfall. Irrigation can also help establish an
off-season planting to maintain its year-round production. In scanty rainfall
and during hot weather irrigating pineapple once in 20–25 days is advisable.
Use of growth regulators
Application of NAA and NAA-based
compounds—Planofix and Celemone @10–20ppm -induces flowering in pineapple.
However, variability in induction of flowering from season-to-season and low
effectiveness of this plant growth regulator during unfavourable weather
are the main factors which have made NAA less dependable. Flowering in pineapple
Kew could be induced with the application of Ethephon or ethrel (2-chloroethyl
phosphonic acid) (100ppm). The concentration of Ethephon could be reduced to
25ppm by combining it with 2% urea and 0.04% sodium carbonate. The
concentration may further be reduced to 10ppm in combination with urea (2%) and
sodium carbonate (0.04%). However, the latter treatment is effective only
during January–May. The application of 50ml solution/plant containing calcium
carbide (20g/litre) or Ethrel (0.25ml/litre) causes flower induction.
Flower induction should be done when the plants attain at least 35–40
functional leaves, so that the plants produce fruits of normal size.
Application of NAA (200–300ppm) 2–3 months after
fruit set increases 15–20% fruit size. To get the year-round availability of
pineapple, it should be planted at regular intervals round the year. Using
suckers and slips of different sizes and crowns as planting material and
applying flower-inducing chemicals also provide its availability round the
year.
Harvesting and
Postharvest Management
Pineapple plants flower 10–12 months after
planting and fruits become ready 15–18 months after planting. Irregular
flowering results in the harvesting spread over a long period. Under natural
conditions, pineapple comes to harvest during May–August. Fruits which mature
in winter are acidic. There is a scope of altering fruit size and
maturation with the use of chemicals or plant growth regulators.
With a slight colour change at the base of
developing fruits, it could be harvested for canning purpose. But for table
purpose, the fruits could be retained till they develop golden yellow colour.
The fruits with the crown, can be kept without damage for 10–15 days after
harvesting.
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 resulting in
the reduction of fruit yield by 49.3 and46.2% in first and second ratoon crops
respectively. Prolonged ratooning results in the reduction of flowering plants,
consumer appeal of the fruit, fruit size and number of fruits suitable for
canning, but in the increase of fasciated fruits. It is also not possible to
prevent the reduction of fruit yield in ratoon crop by increasing the
irrigation or by higher doses of nitrogenous fertilizers.
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