Abstract:
The prevalence of extreme drought and flooding is posing a threat to the food security of
Sub-Saharan African countries. There are national and international calls for actions to investigate
the level of resilience of existing crop cultivars to multiple abiotic stress conditions. A two-year
study was carried out in South Africa to determine growth, development, yield, yield components,
and physiological responses of two contrasting maize cultivars—PAN 413 (drought tolerant) and
PAN 6Q-245 (drought intolerant) under drought and flooding. The drought effect on grain yield
was more pronounced from mid-vegetative to tasselling stages, regardless of the cultivar with yields
deviating from the control by 53–58% (2015/2016) and 34–42% (2016/2017). The effect of flooding on
grain yield was pronounced at the early vegetative stage for both cultivars, with yield reductions
ranging between 26–30% (2015/2016) and 15–21% (2016/2017). Results from the study indicated that
existing maize cultivars (drought tolerant and drought intolerant) are both prone to likely extreme
drought events experienced during the tasselling stage. Results also showed that both cultivars are
prone to probable flooding events before the tasselling stage. It is recommended that plant breeders’
efforts be directed to developing maize cultivars with multiple stress tolerances.
