GENETIC AND MORPHOLOGICAL DIVERSITY IN Monodora myristica(GAERTN.) DUNAL IN EASTERN NIGERIA
CHAPTER 1
INTRODUCTIONÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
1.1 BACKGROUND INFORMATION
Monodoramyristica (Gaertn.)Dunal.,also known as African nutmeg or calabash nutmeg, is a tropical tree of the family Annonaceae (Custard-apple family). Its seeds are widely used as an inexpensive nutmeg substitute because of the similarity between the two in odour and taste. Nowadays, however, it is less common outside its region of production(Celtnet recipes, 2011)
The genus Monodora contains approximately 15 to 20 species including Monodora borealis, Monodoraclaessensii and Monodoragrandiflora.Monodoramyristica is easily recognizable by its very long and pendulous pedicels, an undulate upper bract, a large globose fruit with a black and smooth but finely ribbed surface (Burkill, 1985).     Â
The Calabash nutmeg tree is native to tropical West Africa, where it grows naturally in evergreen forests from Liberia to Nigeria and Cameroon. It is also native to Angola,Uganda and West Kenya (Weiss, 2002). Due to the slave trade in the 18th century, the tree was introduced to the Caribbean islands where it was established and became known as Jamaican nutmeg (Barwick 2004). In 1897, it was introduced to Bogor Botanical Garden, Indonesia, where the trees flowered on a regular basis but no fruit could yet be collected (Weiss, 2002).
1.2 GENETIC DIVERSITY IN PLANTS
Genetic diversity refers to any variation in the nucleotides, genes, chromosomes, or whole genomes of organisms. At its most elementary level, it is represented by differences in the sequences of nucleotides (adenine, cytosine, guanine, and thymine) that form the DNA within the cells of the organism. Nucleotide variation is measured for discrete sections of the chromosomes, called genes. Thus, each gene comprises a hereditary section of DNA that occupies a specific place of the chromosome, and controls a particular characteristic of an organism (Harrison et al, 2004).
