To evaluate the drought tolerance of maize, field methods for comparing genotype productivity under water deficit conditions versus favorable years are used, as well as laboratory methods, such as determining residual leaf water deficit or osmotic stress during seed germination in sucrose solutions.
The most vulnerable periods for maize are the intervals 10–14 days before silking and 15–20 days after it, when moisture deficiency leads to a reduction in the number of ears and grain set. Tolerance is provided by the development of a deep root system and the accumulation of osmolytes, such as proline.
Quantitative assessment is carried out using DI, STI, YSI, and TOL indices, as well as biometric indicators, including 1000-grain weight and ear weight. The FAO index characterizes exclusively the maturity of hybrids and is not a direct indicator of a plant's ability to withstand drought.
General information about the subject — on the page
Drought tolerance.