Far-Red Light Regulates the Circadian Rhythm Pathway to Accelerate Rice Flowering.

Area of Science:

• Plant Science
• Agricultural Science
• Photobiology

Background:

• Early flowering is crucial for rice speed breeding, enabling faster genetic gains and variety development.
• The precise mechanisms of far-red light (FR) in regulating rice flowering and growth remain incompletely understood.

Purpose of the Study:

• To investigate the effects of supplemental far-red light (FR) on rice growth, flowering time, and physiological and molecular responses.
• To provide a theoretical basis for optimizing light environments in controlled facilities for crop speed breeding.

Main Methods:

• Rice plants were grown under three light conditions: control (red-blue-green light), high intensity (HI), and control supplemented with FR.
• Growth parameters, photosynthetic efficiency, chlorophyll fluorescence, physiological profiles (sugars, hormones), and transcriptomic data were analyzed.

Main Results:

• Supplemental FR significantly enhanced vegetative growth, biomass, and photosynthetic capacity compared to control and HI treatments.
• FR treatment accelerated flowering by 12 days (vs. control) and 9 days (vs. HI), increased soluble sugars and starch, and altered hormone levels (elevated GA3 and ABA, reduced IAA).
• Transcriptomic analysis revealed FR activated circadian rhythm and photoperiodic flowering pathways.

Conclusions:

• Far-red light (FR) promotes rice growth and hastens flowering through integrated regulation of leaf expansion, photosynthesis, hormonal balance, and flowering gene expression.
• This research offers valuable insights and technical support for enhancing speed breeding protocols and improving the economic efficiency of controlled environment agriculture.