When does the greatest yield reduction due to drought stress occur in grain sorghum?

The greatest yield reduction due to drought stress in grain sorghum typically occurs during the boot stage. This is a critical period for the plant, as it is when the florets are being formed and prepared for flowering, which directly influences the potential number of grains that can be produced. During the boot stage, the plant is very sensitive to water deficits, and insufficient moisture can severely limit the development of the reproductive structures.

When drought stress is experienced at this stage, it can lead to reduced grain set and fewer kernels per head, ultimately affecting the overall yield. Understanding the importance of moisture during this stage is crucial for effective management and maximizing grain sorghum production.

Moisture availability at earlier stages, although important for growth and development, has less direct impact on final yield than what occurs during the boot stage and subsequent flowering and grain filling stages, where the repercussions of drought stress are most pronounced.