Abstract
Dietary vegetable intake is low in sub-Sahara Africa (SSA) compared to the world's average. This situation is further worsened by low water availability for vegetable production, especially in the dry season. This investigation was therefore conducted to obtain the optimum water requirements in the screen house and evaluation of different moisture stresses based on the derived optimum in two subsequent field trials. In the screen house, water stress treatments were varied as: −6.0, −1.2, and −0.3 bar while in the field trial treatments were combined to vary the field water stress as: −6.0, −1.5; −0.3, −1.5; −6.0, −0.3; −0.3, −0.3 bar (the control). Results in the screen house study showed that optimum soil water potential for amaranth was reached at −1.2 bar compared to all other treatments and that variety NH84/493 performed best compared to all other varieties in all the growth and yield parameters measured. In the field trial, bringing the moisture content from initially dry (−6.0 bar) to −1.5 bar optimum soil water potential favored seedling emergence best compared to all other treatments combinations. However, treatment combination −0.3, −1.5 bar when soil was initially wet (−0.3 bar) then bringing it to optimum (−1.5 bar) gave the best output in terms of seedling establishment and productivity. Variety NH84/493 grown at −0.3, −1.5 bar performed best compared to all other varietal by water stress interactions. We therefore recommended −1.5 bar and variety NH84/493 amaranth for SSA vegetable industry especially for the dry season productivity.