In vitro selection for 2,4-D tolerance in red clover.

Area of Science:

• Plant Biotechnology
• Agricultural Science
• Molecular Biology

Background:

• Herbicide tolerance is crucial for crop production.
• In vitro selection offers a viable method for developing herbicide-tolerant crops.
• Red clover (Trifolium pratense L.) is an important forage legume.

Purpose of the Study:

• To evaluate in vitro selection techniques for enhancing 2,4-D tolerance in red clover.
• To correlate in vivo and in vitro responses to 2,4-D in red clover populations.
• To identify and characterize 2,4-D tolerant red clover callus lines.

Main Methods:

• Eight diverse red clover populations were screened for 2,4-D response.
• Suspension cultures from a regenerable genotype were subjected to two cycles of selection on 0.18 mM 2,4-D.
• 2,4-D tolerance of selected callus lines was assessed using an oat bioassay.

Main Results:

• A strong correlation (r=0.77) was found between in vivo and in vitro 2,4-D responses.
• Sixteen 2,4-D tolerant callus lines were identified.
• Tolerant lines exhibited significantly reduced 2,4-D content, with two lines showing 61% and 83% less herbicide.

Conclusions:

• In vitro selection is an effective strategy for enhancing 2,4-D tolerance in red clover.
• The identified tolerant callus lines can serve as a basis for developing improved red clover varieties.
• This research validates the utility of in vitro selection for herbicide tolerance breeding programs.