Genetic Diversity of Tropical Fruit - Fruit Ripening: Physiology, Signalling and Genomics - page 227

tree genetic resources in the Asian region
alone include more than 500 species of
edible tropical fruits (Ramanatha Rao and
Mal, 2002). Fruits under cultivation
include banana, citrus, mango, pineapple,
papaya, durian, rambutan, jackfruit, litchi,
longan, tamarind, chempedak, carambola,
langsat, guava, sour soup, custard apple
and salak (Verheij and Coronel, 1991;
Singh, 1993; Arora and Ramanatha Rao,
1995), with the predominant fruits being
banana, pineapple, citrus, mango and
papaya. Other than these cultivated
species, many are considered rare or
underutilized. These rare fruits are gen-
erally neglected because they have not
been exploited commercially and therefore
lack improved varieties. Fruit species, both
cultivated and wild, contribute
substantially towards sustainability of the
ecosystems (Ramanatha Rao and Mal,
2002). They are also a source of useful
genes for the genetic improvement of
related crop species. Some of the genera
with rare species of fruits are Garcinia ,
Lansium , Baccaurea , Artocarpus and
Nephelium . Very little is known about the
ripening behaviour and regulation thereof
of several underutilized tropical fruits.

(0.77 million ha). However, with respect to
production, it tops the list with an annual
production of 26.47 million t (Anon.,
2010). The term banana is given to varieties
that are used for fruit and eaten raw,
whereas plantain refers to varieties that are
edible only when cooked. Banana fruit is
rich in phosphorus, calcium and potas-
sium. Banana fruit is a seedless, par-
thenocarpic berry that develops without
pollination and fertilization. The edible
pulp develops mainly from the ovary wall
under an autonomous stimulus of complex
nature in which growth substances are
involved. Sterileness, i.e. seedlessness, is
partially independent of parthenocarpy;
many edible bananas are somewhat fertile
if pollinated. Wild bananas have seedy
fruits that develop only if pollinated
effectively. Banana fruit in general are
negatively geotropic and the shape of the
mature fruit refl ects the posture of the
bunch and the position of the fruit upon it.

13.3.2 Mango (Mangifera indica L., family
Anacardiaceae)

Mango is the most important fruit of India.
It occupies the largest area (2.3 million ha)
among fruit crops, and production-wise
mango ranks second (15.0 million t) with
nearly 21% contribution to the total fruit
production of India. The nearly 1000
varieties of mango cultivated in India
provide an unusual diversity of fl avours
and tastes. It is titled the 'King of fruits'
because of its richness in variety, delicious
taste, excellent fl avour, attractive appear-
ance and popularity among the masses.
India is the largest producer of mangoes in
the world and accounts for more than 55%
of world production.
Mangoes are large drupes. The large,
fl attened, kidney-shaped central stone
contains one or more large starchy embryos
and can constitute up to 20% of the fruit
weight. The skin has a yellow or green
background colour, with a red/orange
blush in many cultivars, and is thicker
than usual for drupaceous fruit. The mango
skin contains irritating oils, particularly in

13.3.1 Banana ( Musa spp., family Musaceae)

The banana is one of the most ancient food
plants, having been used, and perhaps
cultivated, at the dawn of recorded history.
It is a very common plant in the world and
is more highly commercialized than any
other fruit. All of the edible bananas and
plantains are indigenous to the warm,
moist regions of tropical Asia: India
(Assam), Burma, Thailand and Indo-China.
The Island of Honduras and Jamaica are
among the chief banana-exporting
countries today. The banana crop is
cultivated extensively in India, Jamaica,
Costa Rica, Cuba, Honduras, the northern
shores of Columbia, Central America, the
Canary Islands and the West Indies.
Banana ( Musa spp.), including plantain,
is the third most important fruit crop of
India in terms of the area under cultivation