Page 6 - Vol.39-No.6

CROP PROTECTION

SEEDING THE SUCCESS

FOR OIL PALM

a) nigrescens with violet to black unripe 1. Breaking of dormancy
fruits, and ripe fruits with a brown or black 2. Germination induction
cap. b) virescens having green unripe fruits
ripening to reddish orange and c) albescens The Germinator
fruit without the reddish colour because Dormancy break and germination induc-
it lacks carotenoid pigments tion are carried out in the same custom-de-
The tenera type usefully combines a thin signed ‘building’ called a’ germinator’, at
DR. TERRY MABBETT shell (easy to crack during processing), and specific temperatures and seed moisture
a high proportion of pulp. It is the biotype levels and for varying lengths of time. A
usually grown on commercial oil palm plan- typical germinator comprises a separate
Oil palm plantations around the world tations, and dominated by the nigrescens and enclosed heated space for breaking
have their roots in the humid lowland trop- fruit type as a series of commercial hybrids dormancy and an associated ‘cool’ area
ics of Africa and where the African oil palm developed for high oil content. where seeds are placed for germination,
(Elais guineensis) originates. It was first But with plant breeding and the use of all within a custom-designed building.
carried and spread by man from Senegal to sophisticated hybrids come restrictions and The isolated, heated area is an enclosed
Angola in a broad swathe along the coast responsibilities related to the selection and chamber, equipped with double glazed win-
and into the interior along the path of the germination of seed. It is pointless for pro- dows, double walls with, 13 cm space, and
Congo River. ducers to ‘save their own seed’ for these a double layered ceiling all designed to insu-
Oil palm readily grows, multiplies and will just produce a mixture of sterile piserfa, late the structure and maintain the intensity
spreads itself in forest clearings and shifting dura and tenera palms and offering poor and consistency of heat required. Inside
cultivation will typically create large areas performance compared with the improved are 61 cm wide slatted shelves, 35 cm
of semi-wild oil palm groves. Like most plant material of the previous (parental) apart, sufficient to support 10-12 plastic
tropical tree crops, including rubber and generation. bags per metre length of shelf. Each bag
cocoa, oil palm was originally exploited by will contain some 1000-1500 seeds. The
‘gatherer’ communities, who picked nuts building is heated using conduction and
from wild and semi-wild palms. In the nine- convection via hot water pipes or elec-
teenth century enterprising communities tric heaters and is always thermostatically
began to cultivate oil palm by planting seed controlled.
with regular trade in palm oil and kernels
between West Africa and Europe starting Breaking of dormancy
at this time. On arrival at the germinator seeds are
Subsequent development of plant breed- given identifying codes, to distinguish be-
ing technology has produced high fruit and tween hybrids or seeds obtained from an
oil yielding hybrids that underpin today’s individual cross. They are held in an air-con-
large production and processing industries Oil palm nursery ditioned room in darkness at ‘room’ tem-
in Africa. (Picture courtesy Omex) perature until required for heat treatment.
Basically there are three biotypes within What’s more, seeds of the oil palm are At this stage seeds have a moisture content
the species E. guineensis distinguished by slow to germinate with a low germination of about10% weight/weight, and require
the structure of the pulp and shell. This in success rate and a lengthy pre-germination daily soaking for seven days with com-
turn will determine palm fruit quality and period. Germination of oil palm seeds is no plete daily renewal of the water. Soaking
its economic importance. easy business and requires heat treatment and several hours of drying under shade
The three main types of oil palm within so that germination is synchronised so that restores the seeds to the higher moisture
the species are: the seeds ‘all’ produce healthy first shoots level required for breaking of dormancy
1. The dura type which possesses a thick (plumules) and first roots (radicles) at the using dry heat treatment.
same time. It is not a procedure for the
shell, of 2-8 mm thickness and a relative- Seeds are loaded into 50 x 60cm plastic
ly small pulp comprising some 35-70 per small grower but one that is best done by a bags (0.2 mm thickness) to give 1000-
cent of the nut. central authority or large plantation which 1500 seeds per bag. Each bag is metic-
then sells on germinated seeds ready for ulously ‘sealed’ by closing the end with a
2. The pisifera biotype which lacks a shell planting to other growers. series of sequential folds, and finally secur-
3. Tenera, a natural hybrid of dura x pi- There are two vital steps required for ing with heavy-duty adhesive tape. Bags
sifera with a thin shell (0.5-4.0 mm thick- production of germinated seed for planting. are loaded onto the shelves and treated
o
ness) and an extremely high proportion of Both are best carried out using a procedure to a consistent temperature of 39 C for
pulp that exceeds 90 per cent. Tenera is called ‘dry heat treatment’ with seeds in 60-80 days (depending on type of seed).
further classified by colour of the fruit as: polythene bags. They are: Alternatively, growers can conveniently use

4 Vol. 39 No. 6