The paper summarizes research conducted at International Center for Tropical Agriculture (CIAT) on responses of
cassava to extended water shortages in the field aided by modern gas-exchange and water-relation techniques as well as
biochemical assays. The aim of the research was to coordinate basic and applied aspects of crop physiology into a
breeding strategy with a multidisciplinary approach. Several physiological characteristics/traits and mechanisms
underpinning tolerance of cassava to drought were elucidated using a large number of genotypes from the CIAT core
germplasm collection grown in various locations representing ecozones where cassava is cultivated. Most notable
among these characteristics are the high photosynthetic capacity of cassava leaves in favorable environments and the
maintenance of reasonable rates throughout prolonged water deficits, a crucial characteristic for high and sustainable
productivity. Cassava possess a tight stomatal control over leaf gas exchange that reduces water losses when plants are
subjected to soil water deficits as well as to high atmospheric evaporative demands, thus protecting leaves from severe
dehydration. During prolonged water deficits, cassava reduces its canopy