Download 1 - About AIMS

ROSELLE PRODUCTION
Joint publication AREU and University of Mauritius (Faculty of Agriculture)
Introduction
Roselle (Hibiscus sabdarifa L.) of the Malvaceae family, is also known as Oseille Rouge,
Jamaican Sorrel, Karkade, Bissap or Florida cranberry. It is an annual herb that grows to
1.8 m tall or more and is believed to be native of India. Roselle is grown in many parts of
the world mainly for its fleshy red-coloured calyces. The green leaves are consumed as
green vegetable and the stem has good properties for the paper industry. Various parts
(calyces, seeds, roots and leaves) of the plant are also used in traditional medicine.
Nutritive value
Roselle fruits are rich in vitamin C (1.27 mg ascorbic acid/ g of fruit fresh weight) and
anthocyanins which play an important role in maintaining human health. Roselle calyces
exhibit very high antioxidant capacities mainly due to it high an.thocyanins content
Roselle is valued for its mild laxative effect and its diuretic properties.
The aqueous
extracts of the roselle plant are also used for treating gastrointestinal disorders, reduce
cholesterol level, liver disorders and high blood pressure.
The Roselle Fruit
The bright red fleshy calyces are edible and are the most useful part of the plant.
Calyces are separated manually from the seedpods.
Some interesting characteristics of roselle fruits are listed in the table
below:
Fruit weight (g)
Calyx weight per fruit (g)
10 – 12
5–6
Fruit length (mm)
49 – 52
Fruit diameter (mm)
30 – 33
Seed number per fruit (units)
31 – 33
Water content (%)
88 – 89
Acidity (% citric acid equivalent)
2.8 – 3.1
Pectin content (%)
0.6 – 0.8
Climate
Roselle grows well in a wide range of climates except in the super-humid zones. Irrigation
should to be supplied in the sub-humid areas. The crop requires 13 hours of sunlight during
the first 4-5 months of growth to prevent premature flowering. Dry periods can be withstood
and are desirable during the last months of growth for calyx quality.
Soil types
Roselle is quite hardy and grows well in most soils that are deep, fairly fertile and welldrained. It can tolerate poor soils but waterlogged soils should be avoided.
Propagation
Roselle are mainly propagated by seeds. These are collected from the mature pods and
stored under cool, dark and dry conditions.
Propagation by stem cuttings
Roselle can also successfully propagated using stem cuttings. The best
result is obtained when softwood cuttings are dipped in auxins
(commercially available rooting hormones may be used).
Roots are
formed within 2 weeks after planting.
Root formation in roselle cuttings
Rooted stem cuttings are ready for transplantation after one
month
rooted stem cuttings
Crop establishment
Raising of Seedlings
Transplanting
technique
is
recommended
for
crop
establishment. Seedlings are raised during the period of
October to December. Seeds can be broadcasted on beds, sown in deep seedling trays or
plastic bags. These are ready for transplanting 4 to 6 weeks after sowing when they are 15
to 20 cm tall.
Planting season
Transplanting in November results in larger plants by the time of flowering in March/April,
whereas when it is carried out in January, plants may be small when they start flowering.
Transplanting
Holes of 30 cm X 30 cm in size and 20 cm to 25 cm deep are dug at a spacingof 1.2 m –
1.5 m within row and 1.8m- 2.0 m between rows. A quincunx planting system as shown in
the figure below is recommended.
Add basal fertilisers at the rate of 20g of 16:16:23:2.5 (N:P:K:Mg) per hole and 0.5 to 1.0
Kg of well-composted manure. Mix soil, fertilisers and manure and then cover the mixture
with a thin layer of soil.
One seedling is then transplanted per hole.
1.8 - 2.0 m
1.2 - 1.5 m
Irrigation
Roselle is a drought-tolerant crop. However, for maximum fruit yield, watering is highly
recommended. During the first weeks, irrigation should be supplied in the absence of
rain to ensure proper establishment of crop. It is also important to irrigate roselle plants
during the flowering and fruiting stages. Irriagtion should be reduced during crop maturity
as this improves fruit quality.
Fertiliser application
Roselle is not a very demanding crop in terms of plant nutrients as it can perform well on
fairly fertile soils.
But to maximise fruit yield, fertiliser application is recommended as
follows:

20 g of 16:16:23: 2.5 (N:P:K:Mg) per hole at time of planting;

10 to15 g of Calcium Ammonium Nitrate (CAN) per plant, 4 weeks after germination
(10 to 15 cm away from plant); and

15 g of 12:12:18 (N:P:K) per plant, around mid-February (10 to 15 cm away from
plant).
Weed Control
Weed control is mainly done manually. Weeding is required 2-3 times throughout the crop
cycle depending on the weed infestation. No weeding is needed when plants reaches
maturity.
Flowering
Roselle is a short-day plant, that is, flowering takes place when days are short. Flowers are
usually borne at each leaf axil and are visible as from end of March. 3 to 4 weeks after
flowering, petals are shed and the young calyces start growing.
Pests and Diseases
Pests
The main pests affecting roselle are: red ants (Solenopsis
spp.) causing damage to flowers and fruits, chafer beetles
and Lepidopteran larvae making shot holes in the leaves.
Control measure

Red ants : Apply Karate 5 CS “ 0.5 ml/L every seven days

Leaf eating beetles and Lepidopteran larvae: Apply Decis 2.5 EC or Karate 5 CS “
perforated leaf
0.5 ml/L every seven days
Thrips, aphids and mites have been observed but population levels were much below
economic threshold. Root nematodes may also be encountered.
Diseases
No disease of economic importance affecting roselle locally have been recorded. But, in
cases of mechanical injuries, secondary disease infections may occur.
For example,
severe wilting has been observed on roselle plants that were affected by windy and
waterlogged conditions in the field.
Harvesting
Roselle fruits are ready to harvest when the tips of the
calyces are about to open.
This takes place after the flower petals have been shed and
before the seedpods toughen and start to ripen. Harvest is
done manually using clippers (secateurs), preferably during
early morning or late evening.
After harvest, the fruits are kept in clean plastic crates and kept under shade.
fruits in clean crates under shade
The harvest season lasts for 5-8 weeks mainly during mid May to mid July. To reduce cost
of harvesting, the entire plant or fruit-loaded branches could be cut down and taken under a
shed whereby the calyces are quickly separated from the stems.
Postharvest Handling
Roselle fruits need to be handled with utmost care as the epicalyces are fragile. At 4-50C,
clip-on transparent punnets are recommended to store minimally processed roselle calyces.
The calyces may be stored for up to 16 days without major changes in quality.
Yield
Yield of fruits is highly dependent on the cultural practices adopted.
Under a rainfed
condition and without fertilisation, a yield of 8-10 tonnes of fruits per hectare has been
obtained. When irrigated and fertilised, a yield of 16-22 tonnes of fruits per hectare can be
obtained.
Uses and Processing
Roselle calyces are used to
prepare pickle, sweet and sour, herbal tea, jam, jelly,
marmalade, fresh juice, wine, syrup, cordial and candy. Roselle calyces can be processed
and preserved in the following forms: frozen concentrate, individually quick frozen (IQF),
and dehydrated calyces for further processing into the above-stated products.