Variations in Callus Formation and Plant Regeneration in African Rice (Oryza glaberrima Steud)

Area of Science:

• Agricultural Science
• Plant Biotechnology
• Genetics

Background:

• Rice (Oryza spp.) is a vital global food source.
• Efficient plant regeneration is crucial for genetic improvement and crop propagation.
• Understanding cultivar-specific responses in tissue culture is essential for optimizing rice breeding programs.

Purpose of the Study:

• To evaluate callus induction and plant regeneration potential across diverse African (Oryza glaberrima) and Asian (O. sativa) rice cultivars.
• To identify optimal media compositions for maximizing callus growth and plant regeneration in rice.
• To compare the regenerative capacity of different rice species and cultivars.

Main Methods:

• Mature seeds from 18 African and 2 Asian rice cultivars were used for callus initiation.
• Callus induction was performed on a medium supplemented with 2,4-D, with or without coconut milk.
• Plant regeneration was assessed on two distinct media formulations: one with NAA and BA, and another with IAA and kinetin.

Main Results:

• Significant variations in callus size were observed among the 20 rice cultivars.
• Coconut milk addition generally enhanced callus proliferation across most cultivars.
• Plant regeneration was achieved in 16 out of 20 cultivars.
• A medium containing 0.2 mg/L NAA and 11 mg/L BA demonstrated superior performance for plant regeneration compared to the IAA/kinetin medium.

Conclusions:

• Cultivar-specific differences significantly influence callus formation and plant regeneration in rice.
• Coconut milk is beneficial for enhancing callus growth in rice tissue culture.
• Specific plant growth regulator combinations, particularly NAA and BA, are critical for efficient plant regeneration in rice, offering a promising avenue for breeding applications.