Breeding progress is a major contributor to improved regional maize water productivity

Area of Science:

• Agronomy
• Plant Genetics
• Crop Physiology

Background:

• Agricultural water productivity is a key metric for sustainable crop production.
• Maize (corn) yields have risen significantly, but the impact of breeding on water productivity is less understood.
• Rainfed maize yields in the US Corn Belt have tripled since 1950 with stable water inputs.

Purpose of the Study:

• To quantify the contribution of plant breeding to increased agricultural water productivity in maize.
• To determine the genetic component of enhanced water use efficiency in rainfed maize systems.
• To assess the role of genetic gains in biomass and harvest index.

Main Methods:

• Analysis of 61 historical maize genotypes released since 1934.
• Conducted 28 experiments over nine years to isolate genetic effects.
• Calculated changes in grain yield, biomass, harvest index, and water productivity (kg ha⁻¹ mm⁻¹ year⁻¹).

Main Results:

• Maize water productivity increased by 0.191 kg ha⁻¹ mm⁻¹ year⁻¹ (4.2% year⁻¹).
• Genetic improvements contributed 1.9% year⁻¹, accounting for 45% of the total gain.
• Increased water productivity resulted from higher biomass production and improved harvest index.

Conclusions:

• Plant breeding is a major driver of enhanced water productivity in rainfed maize.
• Genetic advancements reduce the need for additional freshwater in agriculture.
• This research highlights the potential of breeding for sustainable intensification of food production.