Coconut

Abstract

Coconut grows in the tropics mainly in coastal areas at low altitudes, in environments of high humidity and high temperatures. Its oil is characterized by a relatively high melting point, narrow melting range, absence of unpleasant odour and a certain resistance to oxidation and rancidity. Coconut oil is rich in short-chain fatty acids and exhibits very good digestibility. In addition to its food uses, coconut oil is widely used as an industrial vegetable oil. Because of its multitude uses it has been termed as one of nature's greatest gifts to mankind and also as the Tree of Life. Coconut (Cocos nucifera L.) is a monocot belonging to the family Arecaceae, subfamily Cocoideae and is the sole species of the genus Cocos. Coconut possesses a diploid genome with 16 pairs (2n = 2x = 32) of chromosomes. Classifications proposed identify two main varieties of coconut, tall or typica and dwarf or nana. Tall is the commercially viable variety while dwarf has been used extensively in genetic improvement for producing hybrid coconuts. High nut yield has been the primary objective of coconut breeding followed by precocity, low stature and the tolerance to biotic and abiotic stresses. Coconut breeding is hindered by a number of factors such as long generation interval, cross pollination breeding behaviour of tall coconuts resulting in highly heterogenous populations, low number of seeds produced per palm and the lack of a viable vegetative propagation method. Mass selection and hybridization have been the widely used breeding methods of improvement and at present the majority of the genetically improved coconut plantations have been derived through mass selection. The hybrids between tall and dwarf types have become popular due to their higher nut yields, precocity and the lower stature compared with tall coconuts. Biotechnology offers prospects to overcome some of the inherent constraints in coconut breeding. Molecular marker systems such as RAPD, AFLP, SSRs and DArT have been used extensively for the genetic diversity studies and development of several genetic linkage maps.