Mechanisms of Drought Tolerance in Coffee (Coffea arabica L.): Implication for Genetic Improvement Program: Review

: Drought is a limiting factor of coffee production and industry worldwide which result 40-80% yield loses. The most substantial solution for this factor is developing tolerant coffee variety. In order to design genetic improvement program, understanding the mechanisms exhibited by drought tolerant and desirable traits involved in coffee genotypes under drought stress is priority issue. Thus, the present review article was conducted with the intension to assess and to understand the drought tolerance mechanisms revealed in coffee for further genetic improvement program. So far, the achieved research results on drought tolerance mechanisms of coffee such as morphological, physiological, biochemical and molecular mechanisms were clearly discussed in this article. Drought tolerant coffee genotypes exhibited deep root, reduce leaf area and even shade leaf, control on stomatal conductance and leaf transpiration under water deficit. Under drought stress, several biochemical accumulation such as sugar, amino acid, carbon metabolism enzymes Viz sucrose synthase and phosphofructokinase were confirmed in drought tolerant coffee which favor osmoregulation and enable desiccation tolerance. Coffee breeders’ experts should be conscious these desirable traits during coffee genetic improvement for drought tolerance. In Arabica coffee, CaERF017 is the most expressed gene under low temperature and drought stress. Generally, many genes identified in Coffea arabica and Coffea canephora that response to drought stress which are essential for intra and inter- cross for genetic enhancement and developing drought tolerant coffee variety.