II. Tropical Root Crops
Tropical root crops are planted primarily for their edible roots, corms, or
cormels. In this regard, tropical root crops require a longer period of time
to mature than many other vegetable crops. Some root crops take as long
as 14 months to reach maturity. Some people also eat the edible leaves of
both cassava and taro. In the case of both these crops, plants grown for
edible leaves can be grown in cooler locations than would otherwise be
possible. For pest control products, these crops are included in root and
tuber vegetables.
Botany and Planting
Table 15.3. Planting information for cassava, taro, and malanga.
Planting dates Cassava Taro Malanga
Miami-Dade County Year-round
(mainly February
to April)
Year-round Year-round
Planting information
Distance between rows (in) 48 52 52
Distance between plants (ft) 2 1 1
Planting depth (in) 3 - 4 4 - 6 4 - 6
Propagules needed per acre 5,445 2,420-3,630 2,420-3,630
Minimum propagule size 10-12” stick or
micro-propagules
2 oz 2 oz
Bedded No Yes Yes
Months to harvest from planting 8-12 6-10 9-14
Plant populations (acre) 5,445 10,052 10,052
Cultivars
Cassava – Known the world over by a variety of names including
manioc, yuca, mandioca, balinghoy, kamoteng, kahoy (Philippines),
mogo (Africa), tapioca root (India), and manioc root in its native South
America. Though the exact origins of cassava are unknown, it was likely
domesticated between 7,000 and 9,000 years ago in the Amazon. This
root crop is grown throughout tropics and has become an important dietary
stable in many parts of the world.
Varieties are often separated based of their cyanogenic glucoside (HCN)
content into either low HCN, a.k.a. “sweet,” or high HCN, a.k.a. “bitter,”
to accompany the HCN. Though no named varieties are currently known in
southern Florida, ‘Senorita’ was locally popular in the 1980s and attempts
were made to introduce the CIAT variety ‘Mantiqueira’ at that same time
because it produced acceptable yields even with high levels of rootknot
nematode infestation. The range of local genotypes covers a few unnamed
clones that have been imported from various Caribbean basin countries.
Federal regulations prohibit further importation of cuttings or botanical seed.
Root development may occur as early as 28 days after planting though it
thickening but the number of roots that will eventually thicken is determined
early in the life of the crop with little change in the number of thickened roots
after three months. A soil fertility analysis is conducted as a routine practice
to ensure an adequate amount of potassium is maintained in the soil to improve
root development for improved yield. The amount of nitrogen available
to the crop is often limited because excessive nitrogen increases vegetative
growth rather than the root development.
by scientists at the International Institute for Tropical Agriculture (IITA) in
Ibadan, Nigeria where one makes 2-node cuttings or ministakes that can
provide a 5-fold increase in the production of propagules from each parent
cassava plant. According to IITA, “these ministakes are easily moved
and protected in plastic sacks until they can be grown on and hardened in
It takes 8-12 months for cassava roots to reach maturity. Plants are often
cut back two weeks prior to harvest, resulting in increased tuber size and
yields about 10% higher.
exist among consumers, though the ability to satisfy these requests is very
limited given the very small number of varieties currently grown in the U.S.
Taro
a few unnamed Polynesian types are grown for the Asian market. The name
taro is generally used to refer to Colocasia esculenta, one of several major
root crops in the Araceae (Aroid) family.
There are several important crops throughout the tropical regions of the
world related to taro and grown in certain Florida locations. These include
the giant swamp taro, the giant taro, and cocoyam. Each of these Aroids has
several other common names depending on the region of the world.
Information about taro in Florida is limited due to a small acreage.
However taro can be cultivated under both wetland and dryland conditions
with with the latter reffered to as ‘dasheens’ in Florida. Most will mature in
commercial production. The corms are washed of soil, sorted by size, and
packed. The recommended cold room temperature for prolonged storage is
45-50 oF with a relative humidity of 85.
Tannia – is widely grown and used in the tropics and has been grown
on a limited commercial sale since 1963 in South Florida where it typically
planted in the spring since the crop requires 9 to 10 months to reach
maturity and can be injured by frosts. Tannia can be propagated by several
methods: (1) plant the top (head), (2) plant the whole main tuber, (3) plant
pieces of the main tuber, or (4) plant individual secondary tubers. Propagative
materials should be set 3 to 5 inches below the surface. ‘South Dade
Tropical sweetpotato – ‘Picadito’ is the main variety grown in Miami
Dade County. It has deeply lobed leaves and wine colored skin.
It is illegal to import sweetpotatoes into the U.S. and there is no program
to produce disease-free planting material of ‘Picadito’ in Florida. Other
sweetpotatoes which may grow well in Florida and which may be available
276 2019 Vegetable Production Handbook of Florida