[Shade-tolerance indices of maize: selection and evaluation]

Area of Science:

• Agricultural Science
• Plant Physiology
• Crop Science

Context:

• Maize (Zea mays L.) is a vital global crop susceptible to yield loss under reduced light conditions.
• Understanding shade tolerance is crucial for optimizing crop production in intercropping systems or areas with natural shading.

Purpose:

• To investigate the impact of 50% shading on morphological, physiological, and yield traits of 24 maize cultivars.
• To identify reliable indices for evaluating maize shade tolerance in field conditions.

Summary:

• A field experiment revealed that 50% shading negatively affected plant height, stem diameter, photosynthetic rate (Pn), specific leaf weight (SLW), dry matter accumulation, and yield components.
• The anthesis-to-silking interval (ASI) increased, and grain yield decreased significantly under shading.
• Percent changes in ASI, Pn, SLW, and kernels per row correlated with dry matter accumulation and grain yield, serving as effective shade tolerance indicators.

Impact:

• Identified 14 shade-tolerant and 10 shade-sensitive maize cultivars based on a comprehensive trait analysis.
• Demonstrated the practicality and objectivity of using morphological, physiological, and yield traits for evaluating maize shade tolerance.
• Provides valuable data for breeding programs aiming to develop maize varieties with enhanced shade tolerance.