Tamarind monograph.pdf - Crops for the Future

Chapter 6. Reproductive Biology
6.1 Introduction
D.K.N.G. Pushpakumara and H.P.M. Gunasena
Natural or unselected tamarind is a long-lived tree and once it starts bearing,
its fruiting capacity increases with age. The productive life of a tree can last
for 50-70 years after which it declines. The normal lifespan of the tree is
approximately 150 years.
It is important to understand the variation in time of the juvenile phase and
genotypic and phenotypic variations in flowering, fruit setting and
productivity so that domestication can be enhanced. See Plates 10-15 for
variation in flowers and fruits.
This chapter summarises what is known about the reproductive biology of
the tree.
6.2 Flowering and fruiting phenology
In tamarind, terminal vegetative shoots which bear flowers only in the
following flowering season are produced annually. Two types of terminal
shoots have been observed by Nagarajan et al. (1997), short ones with an
erect habit and long ones with a drooping habit. This has been identified as
a useful character to evaluate genotypes, since terminal shoot length and
foliage production are found to be highly correlated. In an inflorescence the
flowers only open on alternative days. Flowering and fruiting times vary
from country to country and region to region depending on the latitude and
altitude. It is reported that production of flowers varies considerably between
selections in India. Those with longer vegetative terminal shoots produce
more flowers. The range of variation of flowering and floral organs is
illustrated in Table 6.1.
In general, flowering and fruiting of tamarind takes place in the dry season.
An extended spell of dry weather may be essential for fruit development,
and trees which grow in the humid tropics without this dry spell often do not
bear fruit. At higher altitudes shoots grow mainly in spring and flower
throughout the summer. In the monsoon climate of East Java the tree
changes its leaves towards the dry season (September to November), and
some trees may be nearly leafless during this dry period. Shoot growth
continues through the rainy season (November to April) during which period
flowering occurs. In Thailand, tamarind sheds its leaves and produces new
ones towards the end of the dry season (March to April). Sometimes trees
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