INTRODUCTION.
The term FRUIT can be defined according to
origin (etymological definition), meaning of the word fruit (literal
definition), botanically or horticulturally.
A more practical definition: A fruit is the reproductive body of a
flowering plant that has an edible more or less sweet pulp, usually being used
as or in a dessert or sweet course of a meal.
Importance of fruits
Ø
Fruit crops are used as food that meets dietary needs
of human being.
Ø
Fruit crops have nutritional values such as it is the
source of vitamin and minerals, energy, protein and fat.
Ø
Used as source of income direct and indirect.
Ø
Land tenure security
Plant population refers to
the number of plant per unit area. Normally expressed number of plant per ha.
The role of plant population in crop production.
Ø Having an optimum yields per unit area
Ø To ensure an equal land utilization
Ø Ensures proper utilization of soil nutrients hence
high quality and quantity produce.
Ø Equal proper use of moisture.
Ø To allow the use of mechanization.
Plant density is the number
of plants per unit area expressed as number of plants per m2.
Plant population (pp) = Area(A)
x number of plants/hills
Spacing (Row spacing(R) x plant spacing (P)
Example: Given the spacing
of orange of 30cm x 90cm =0.3m x 0.9m =0.27M2.
From the given formula (pp)
= 10,000m2x 2
0.27m2
=
74074 plant/ha.
i) Seed rate determination
Ø A seed rate is the amount of seeds required per unit
area. It is expressed in gms or kg.
Seed
rates (kg/h) = number of plant/m2
x weight of 1 seed
Germination%
Example: Given plant
population = 74074plant/ha
Spacing = 30cmx90cm = 0.3m x0.9m = 0.27 m2
Area =1ha = 10000m2
Number of seeds per hill = 2
Weight of 1000seeds = 0.2kg
Weight of 1 seeds =
0.0002kg.
% Germination = 80% =0.8
From the formula given Seed
rate (kg/h) = number of plant /m2 x Weight of 1 seed
Germination%
Seed rates = 74074 x0.0002
0.8
Seed rate = 18.5185= 19 kg/ha.
MANAGEMENTS OF
FRUIT CROPS.
Managements of fruit crops
includes seed rates determination, pruning, fruit propagations (budding,
grafting, cutting,) weeding, watering, fertilization, staking, insect pests and
diseases managements, etc.
ii) Wedding Involves the removal of weeds (unwanted plant) which compete with fruit crops
for space, light, water and nutrients. Weeds can be removed using hand hoe,
disc harrow, mulching or application of herbicide like gramoxon.
iii) Fertilization- cultural
practice of adding plant nutrients to the soil or other growing media
iv) Staking is the application
of physical techniques which provide support on
which fruit may naturally grow.
v) Fruit Propagation is a science and art of multiplying fruit crop. Fruit propagation can
be sexual or asexual propagation.
Sexual
propagation is the multiplication of fruit crops by using seeds.
Asexual
propagation involves reproduction from vegetative parts of fruit plants. The method of
asexual propagation of fruit crops includes grafting, budding, cutting etc.
Ø
Grafting is the
process of joining together root stock and scion to form one plant or the joining of separate plant parts
together, such that they form a union and grow as one plant. The
upper portion of the graft combination is called the scion (i.e. plant which
consist of more than one bud) and the part which forms the root is termed the rootstock,
or under stock or just the stock. Scion
should come from the plants which are free from diseases; the scion should be
the one which is mature and of good size. Sometimes scion is soaked in
fungicide for overnight to prevent diseases. Example of fruit that can be
propagated by grafting is the mango fruit.
Ø Budding is a
propagation technique in which a single bud from the desired scion is used
rather than an entire scion containing many buds or is the process of
associating a root stalk with a single bud. Example of fruit that can be
propagated by budding is citrus.
Ø Cutting is a plant part that when removed from
the parent plant and placed under the proper environmental conditions forms
adventitious roots and/or shoots.
Nursery is the place where fruit seeds are raised and then transplanted to the
main field.
Both
sexual and asexual propagation of fruit crops require nursery where plant can
stay for a period of time for adaptability before send to the main field. Two
types of nursery are known the secondary nursery and primary nursery.
Primary nursery is the place
where seedlings are raised before transporting them to the secondary nursery.
The primary nursery should be in protected area away from direct sunlight and
rainfall. The media used in primary nursery is sandy because plant stay for a
short period of time thus does not require media which rich in high nutrients,
also sand soil provide space for aeration, root forming and penetration.
Why establishing primary
nursery?
Ø
In the primary nursery
help to select vigorous seedling to secondary nursery.
Ø
Some fruits are
polyembryo form two seedling per plant thus it help us to separate them in
secondary nursery and plant them to each pot.
Ø
Also in primary
nursery plants will have time to form roots.
Propagation techniques used
in primary nursery include using seeds and cuttings.
Propagation in
secondary nursery is done either by budding or grafting propagation techniques.
The Medias used in secondary nursery should rich on nutrients since plants stay
for a long time and will have time to form roots. Such media should have
mixture of forest soil, farm yard manure, sand or sometimes being replaced by
rice husks used purposely for drainage of water and root penetration.
CITRUS.
Species of citrus.
|
BOTANICAL NAME
|
COMMON NAME.
|
|
1.Citrus sinensis
|
Sweet orange.
|
|
2.Citrus aurautium
|
Sour orange.
|
|
3.Citrus reticulate
|
Tangerine
|
|
4.Citrus
limon
|
Lemon
|
|
5.Citrus auntfolia
|
Lime
|
ORANGES.
Family: Rutaceae
Genus: Citrus
Specie: Sinensis
Botanical name: Citrus
sinensis.
Varieties of oranges are
Washington navel, Valencia, novel, Hamlin, jalla etc.
USES.
Ø Eaten raw as fruit
Ø Used in making juice and squash
Ø In making jam
Ø In making citrus molasses.
Orange.
Distributed in Tanzania in areas like Lushoto, Lindi, Kyela, Ukerewe,
Mtwara, Rufiji, Korogwe, Mombo, Muheza, Pwani and Morogoro.
Ecological requirements.
Require altitude from 0- 2000m above sea level.
Rainfall: 1200mm well distributed.
Soil: should be well drained and fertile soil; avoid water logged areas,
course sand –heavy loam with pH 5.6.
Temperature: Optimum temperature 25 oC -30oC.
Above and below this temperature the growth diminishes and stops completely.
Maximum temperature 38oC and minimum temperature 13oC.
High temperature at night is harmful due to the following;
Ø Respiration and
transpiration continue at high rate while photosynthesis decreases sharply.
Ø Pigmentation of
fruits does not take place on the contrary coloured fruits may regreen.
Oranges require nursery like other fruits. The nursery should be
prepared early enough. High enough organic manure should be added.
The size of the beds should be 180cm wide, 10m long.
Sowing: the seeds should be sown 70cm between seedbed, 5cm plant to
plant and 30cm row to row.
Extraction of rough lemon seeds.
Take the lemon fruits which are matured and ripe but free from
infection. Cut the fruit into halves and squeeze seeds. Subject the seeds to
floatation test then sow them fresh.
Transplanting from secondary
nursery; 30cm between plant and 90cm between rows, this is done after three
months after one germination has taken place.
Vegetative propagation of orange is by grafting, budding and air
layering but is most successful by budding. Budding is done in 6 months after
pricking out to a secondary nursery then after 6 month transplant to the main
field.
Transplanting to the main
field;
Ø Oranges........................6x6metres
Ø Tangerine......................5x5metrres
Ø Grape...........................7x7metres
Ø Pomelo.........................7x7metres
A good bud should be taken from;
Ø Healthy mother
plant
Ø Should be roundish
and greenish brown
Ø Should not be
angular and too green.
For successive grafting and
budding the following condition are necessary;
Ø The stock must be
compatible
Ø The cambial region
of scion must be in intimate contact with that of the root stock.
Ø The stock and scion
must be in a proper physiological stage
Ø Immediately after
grafting all cuts must be protected from drying out.
Weed control: By hand hoe,
herbicides like gramoxon 150-200ml/20litres water, disc harrow, mulch.
Watering mostly done during
dry weather.
Pruning; remove all
unwanted branches which have dried, drupy, interlaced, one metre high branches,
branches below the budded area.
Insect pests;
i)Orange dog moth ( papilio
demodocus)
Ø Symptoms;
defoliation
Ø Control; hand
picking and spray chemicals
ii) Citrus aphids ( Toxoptera
aurantic)
Ø Symptoms; black
soot on fruits
Ø Control; spray
malathion
iii) False codling moth ( cryptophlebra
leucotrota)
Ø Symptoms; fruit
change colour from green to yellow on one side, hard rind, premature falling of
fruits.
Ø Control; remove all
infested fruit and burn
Iv) Purple scale (Lepidosaphesnbeckii)
Ø Symptoms; Curling
of leaves and plant become stunted
Ø Control; spray malathion
and karate.
Diseases;
i) Scab fungus (Elsinoe fawcettii)
Ø Symptoms;
Distortion of leaves, grey to light green colour on fruits.
Ø Control; spray
fungicide
ii) Brown rot fungus (Phytophthora
citrophthora)
Ø Symptoms; Brown
discolouration on tips of leaves in a v- shaped, falling of leaves while green.
Ø Control; keep weed
free, spray fungicide.
iii) Blue and green moulds ( Penicillium
italicum)
Ø Symptoms; water
soaked on fruits, roting of whole fruit.
Ø Control; Harvest
fruit when no dew.
Harvesting signs; Changes of colour
from green to yellow and the fruits test sweetness
Harvesting methods; Hand picking is
preferred
The seeds grown direct from seed takes 5-7 years from planting to
harvesting while the budded seedling take 2-3 years.
Yields; 250-350kg/tree/season,
75000-90000kg/ha (40-80tons), 5000 fruits/season/tree.
Packing of fruits; Fruits are packed
in well ventilated wooden boxes and arranging them in layers alternating with
grass
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