Delayed flowering time when combining warm temperature and short days in barley

Area of Science:

• Plant Science
• Agricultural Science
• Genetics

Background:

• Flowering time is crucial for crop yield and is influenced by genotype and environment.
• Previous field observations noted delayed barley flowering in warmer seasons, particularly with early sowing under short photoperiods.

Purpose of the Study:

• To investigate the complex interactions between photoperiod, temperature, and vernalization on barley flowering time.
• To determine if observed delayed flowering was due to vernalization sensitivity or a photoperiod x temperature interaction.

Main Methods:

• Conducted controlled environment (chamber) and outdoor experiments with barley cultivars.
• Tested responses to cool (12°C) vs. warm (19°C) temperatures and short vs. long photoperiods.
• Assessed plants after vernalization and non-vernalization treatments.

Main Results:

• No vernalization response was observed in any cultivar.
• Warm temperatures and short photoperiods caused abnormal development or flowering failure in some plants.
• Under short days, warmer temperatures delayed flowering in insensitive cultivars but did not advance it in sensitive ones.
• The construction phase of stem elongation duration better predicted flowering time than the foundation phase.

Conclusions:

• Barley flowering time is not sensitive to vernalization.
• A complex photoperiod x temperature interaction significantly affects flowering time and development.
• Final leaf number is a more decisive factor than phyllochron in determining flowering time responses.