Agriculture Reference
In-Depth Information
dominance over axillary buds. One to a few suckers are produced, which,
when harvested, result in the production of additional suckers. Once plant
reserves are exhausted, a sucker can be allowed to grow and gouged when of
reasonable size, resulting in the production of additional suckers. In Okinawa,
crown leaves planted in sand produce plantlets at the leaf base. Only one
plantlet is produced per leaf at a low rate. As no axillary buds are present on
the leaf, shoots must be generated from meristematic callus formed at the leaf
base tissue or from stem tissues adhering to the leaf base. From 40 to 70 leaf-
bud cuttings can be produced from a single crown.
Plantlet production is induced by treating plants with the morphactin
chlorofl urenol (Maintain CF-125 ® ; Multiprop R ® ) after reproductive develop-
ment has been forced with ethephon. Chlorofl urenol is applied 1 or 2 days after
forcing and before signifi cant fl ower dif erentiation has occurred. If timing and
concentration of chlorofl urenol are appropriate, up to ten good-sized plantlets
are produced (Hepton, 2003). Plantlets have also been produced by meristem
culture, but care must be taken to prevent excessive somaclonal variation. It
is reported that up to one million plants can be produced from a single bud in
2 years through tissue culture, but this technique is generally more expensive
than other propagation techniques.
Field preparation and layout
The fi rst step in fi eld preparation on an established pineapple farm is the
destruction of existing plants, since pineapple can be a serious weed if live
plants are plowed under. The fresh plant mass in a ratooned pineapple fi eld is
huge, and residue incorporation or disposal is a costly step in fi eld preparation.
Plants usually are disced multiple times or chopped to hasten desiccation,
and when thoroughly dried are plowed under or burned. The decision as to
whether to plow or burn is often determined by how soon the fi eld is scheduled
for replanting. Conventional tillage implements are used for primary land
preparation on most pineapple farms and plantations, though in Hawaii, a
tefl on-coated moldboard plow was developed that would scour in clay soils and
that permitted fi elds to be plowed to a depth of more than 80 cm. Deep plowing
aids in the incorporation of the large amounts of plant residues produced by a
pineapple crop. Except where deep plowing is done, the size of equipment used
is determined mostly by farm size. Where the soil is compacted, subsoiling is
desirable to break the hard pan to improve drainage and soil aeration. Discing
to break up soil clumps and improve soil texture is important to improve
dispersion of fumigants and to provide good plant-to-soil contact.
Black polyethylene mulch ( 50 microns thick and 81 cm wide) helps to
prevent rapid escape of fumigants, maintains warmer soil temperatures during
the cool season, retains moisture at the soil surface, reduces fertilizer leaching
during rainy periods, controls weed growth in the beds and increases yield. In
 
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