Yield, Agronomic Characteristics and Variability

 of 'Regular Maricongo' and

 'Dwarf Plaintains' (Musa AAB)

Using Tissue-Cultured Plantlets in St. Croix, USVI

 C. Ramcharan A. Gonzalez
 Fruits Crops Program, Agr. Expt. Station
 College of the Virgin Islands


 Overall genetic reversion of 'Regular Maricongo' and 'Dwarf
Plantain' using tissue-cultured plantlets was 29% both in the
1st ratoon and plant crop. Of this percentage the 'Regular
Maricongo (Horn) Plantain' showed a 21% reversion to the
'Congo' or 'Tall French Plantain.' Variability in the dwarf
clones was greater with 38% reversion to the 'Dwarf
French'('Platano congo enano'). The latter cultivar is unique to
this area since there are no reports of its widespread occurrence
in the Caribbean so far. The variant 'Dwarf French' type gave a
yield of 46 tons/ha or 226,460 fruits/ha with an average of


130 fingers and 9 hands per fruit bunch. The 'Regular
Maricongo' or 'Horn Plantain' yielded 14.4 tons/ha or about
61,841 fruits/ha. The Dwarf French types were the shortest
plants (1.95 m) and had the thickest pseudostems (19.05 cm
diam.). However, both French types, Tall' and 'Dwarf ap-
parently needed more days to flower and for maturity of
bunch. The mutant 'Dwarf French Plantain,' an apparently
new cultivar produced in this trial, seems to be well adapted to
local conditions. Further ratoon crops are being closely
monitored for yield, variability and agronomic characteristics.


 Although plantains are grown in West Indian islands, substan-
tial quantities are produced in the Dominican Republic, Haiti,
Cuba and Puerto Rico (Ittyeipe, 1983). The demand for this fruit
crop is high in the Virgin Islands, with almost all the local needs
met by importation from neighboring islands. In an effort to
boost local production, trials were initiated in St. Croix to in-
crease acreages of plantains using tissue-cultured plantlets. Much
of the published research on plantain in the Caribbean has been
devoted to mineral nutrition requirements (Irizarry et al., 1981;
Walmsley, 1974) and nematodes studies (Irizarry et al., 1979)
with little on the feasibility of using tissue-cultured material
(Berg and Bustamante, 1974).
 Present research is being focused on evaluating clones under
standard fertilizer and crop protection practices.
 The purpose of this paper is to present an ongoing preliminary
field evaluation of plantain varieties grown from cloned material.

MATERIALS AND METHODS
 This study was conducted at the V.I. Agricultural Experiment
Station on St. Croix, USVI. The climate is tropical, with an annual
average maximum and minimum temperature of 30.C and 23C,
respectively. The average annual rainfall is 1092 mm. The soil is a
Fredensborg clay loam, 25-38 cm thick with an underlying layer of
limestone or marl. The soil pH ranges from 7.5 to 8.2.
 The experiment was initiated in March 1982 using stage 3
plantlets of 'Maricongo' and 'Dwarf Plaintain,' two granular
nematicides, and Diazinon 2E as a soil drench. Plantlets were
shipped into St. Croix from Oglesby Nursery of Holiday, Florida.
Field preparations consisted of ploughing, discing and incor-
porating 3.5 kg of well-rotted poultry manure in the planting
holes. Experimental plots had six plants of each cultivar spaced at
1.8 m x 3.0 m to give an approximate density of 1742 plants/ha.
Three nematicide treatments were replicated three times in a
completely randomized design. The nematicides used were
Temik (aldicarb) 10% G and Furadan (carbofuran) 5% G;
Diazinon 2E was used as a soil drench to test its effectiveness for

VOL. XX-PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY


nematode control. These were incorporated at the time of plant-
ing and again at 6, 4 and 2-month intervals respectively on the
soil surface. Weeds were controlled with post-emergence applica-
tion of Gramoxone at 473 cc/ha. Ammonium sulfate and
muriate of potash fertilizers were applied every two months at the
rate of 280 g/plant up until flowering. Six months after planting,
138 Fe Sequestrene at 9.3 g/plant was watered in around each
plant, because a general foliar chlorosis had occurred. From the
first ratoon appearance, a constant supply of Fe was injected
through the drip irrigation system.

RESULTS AND DISCUSSIONS
 Of major significance in this work, was the reversion of
'Regular Maricongo' and 'Dwarf Plantain' clones to the 'Tall
French' and 'Dwarf French' plantain types respectively. A com-
bined reversion of 29% occurred in the first two harvests. Of this,
the 'Regular Maricongo (Horn) Plantain' showed a 21% reversion
to the 'Congo' or 'Tall French Plantain' (Table 1). Variability in
the 'Dwarf clone was greater, with 38% reversion to the 'Dwarf
French.' Variability therefore did not differ much between plant
crop and first ratoon. This would indicate that further ratoon
crops might be stable and true to type. As a result of reversion,
four varieties of plantain were eventually evaluated instead of the
two originally planted.

TABLE 1. Percent reversion of 'Horn' and 'Dwarf Plantains' in plant and first ra-
toon crop.

 A% % Average
 Reversion Plant Crop Reversion in 1st Ratoon Reversion for
 Initial Cultivar 1983 1984 Two Crops
 Horn Plantain
 To
 Tall French 23.5 19 21.2
 'Dwarf Plantain
 arf trench 31.2 44 7.
 'Dwarf French" 31.2 44 '37.6


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