To quantify maize tolerance, stress resistance indices are used, based on a comparison of hybrid yields under stress and favorable conditions, including the Tolerance Index (TOL), Stress Tolerance Index (STI), and Stress Susceptibility Index (SSI). These indicators allow for the ranking of breeding material based on their ability to maintain stable productivity.
Assessment methods include field trials with controlled moisture deficits as well as laboratory analyses. These include fluorimetry to evaluate the state of the photosynthetic apparatus, the cold germination test to determine seed cold tolerance, and biochemical monitoring of the activity of enzymes such as peroxidase and catalase, which respond to stress.
When studying tolerance to specific factors, such as high density or shading, morphological changes are analyzed: development dynamics from emergence to flowering, plant height, and ear parameters. The use of tolerant hybrids allows agronomists to minimize grain losses and ensure yield stability in high-risk agro-climatic zones.
General information about the subject — on the page
Tolerance.