Macro Nutrient Use Efficiency of Cacao Genotypes Under Varying Levels of Nutrient Availability.

Cacao (Theobroma cacaoL) is a perennial crop of great economic importance to many tropical countries of South and Central America, Lack of adequate soil nutrients such as N, P, K, and Fe are affecting the production potentials and sustainability of cacao. Series of greenhouse and growth chamber experiments were undertaken to assess deficiency and sufficiency levels of essential nutrients on macro nutrient use efficiency in various cacao genotypes. Levels and forms of N and source of Fe had effect on macro nutrient use efficiency in cacao genotypes. Cacao genotypes responded differently for macro nutrient use efficiency to deficiant to sufficiency levels of K and P in growth medium. Various methods adopted in our studies appear to be suitable for identification of cacao genotypes that are efficient in nutrient use efficiency in soils with deficient and sufficient levels of essential nutrients. Understanding of nutrient uptake efficiency traits influenced by levels of soil fertility will help in identification of cacao genotypes efficient in utilization of low soil available essential macro nutrients and such genotypes could be used in crop improvement programs to evolve superior cultivars for any given soil nutrient status.