Cultivar evolution underpins maize yield sensitivity to adverse climate conditions

Area of Science:

• Agricultural Science
• Plant Genetics
• Climate Adaptation

Background:

• Cultivar evolution is vital for food security, yet its role in yield gains from climate adaptation is unclear.
• Maize (Zea mays L.) is a critical global crop, facing diverse climatic challenges across regions.
• Understanding genotype-environment interactions is essential for sustainable agriculture.

Purpose of the Study:

• To quantify the contribution of cultivar evolution to maize yield gains in China from 2001-2020.
• To assess the impact of climate variability and extreme events on maize productivity across different Chinese regions.
• To investigate how breeding influences crop sensitivity to heat and precipitation stress.

Main Methods:

• Compiled a large dataset of 48,797 cultivar-site-year observations across four major Chinese maize regions.
• Analyzed yield trends and correlated them with regional climatic conditions (temperature and precipitation).
• Quantified genotypic sensitivity to climate stress (heat and precipitation) over time.

Main Results:

• Maize productivity increased by 0.3-2.8 Mg ha⁻¹ per decade due to cultivar evolution.
• Yields in Northeast China (NEC) and North China (NC) are sensitive to summer heat stress.
• Southwest China (SWC) and Northwest China (NWC) yields are constrained by precipitation variability; breeding increased this sensitivity.

Conclusions:

• Cultivar evolution is a primary driver of long-term maize yield gains in China.
• Breeding strategies must address regional climate constraints, including heat and precipitation.
• Developing climate-resilient cultivars is crucial for future food security under changing environmental conditions.