Targeting enhanced digestibility: Prioritizing low pith lignification to complement low p-coumaric acid content as...

Area of Science:

• Agricultural Science
• Plant Biology
• Animal Nutrition

Background:

• Forage maize is vital for dairy cow diets, with drought impacting yield and digestibility.
• Previous research focused on inbred lines; forage maize hybrids lack similar studies on drought effects.
• Understanding these impacts is critical for hybrid registration and maintaining milk production.

Purpose of the Study:

• To investigate the effects of water and heat stress on forage maize hybrid digestibility.
• To identify the key factors controlling digestibility under stress conditions.
• To inform breeding strategies for climate change adaptation.

Main Methods:

• Cultivated eleven modern forage maize hybrids over two years under four controlled water stress levels.
• Conducted agronomic, biochemical, and histological analyses for multiscale trait assessment.
• Developed a comprehensive heat and water stress index to classify environmental conditions.

Main Results:

• Severe stress reduced ear production but maintained dry matter digestibility via enhanced cell wall digestibility.
• Increased cell wall digestibility resulted from reduced p-hydroxycinnamic acid and altered lignin distribution.
• Lignin distribution's impact on digestibility intensified with stress severity, becoming the sole determinant at extreme levels.

Conclusions:

• Forage maize digestibility can be maintained under stress by modifying cell wall components.
• Further research should focus on carbon flux effects on p-hydroxycinnamic acid and lignin.
• Incorporating moderate stress in breeding programs is essential for developing climate-resilient forage maize hybrids.