Methods for performing crosses in Setaria viridis, a new model system for the grasses

Area of Science:

• Plant Science
• Genetics
• Bioenergy Research

Background:

• Setaria viridis is a valuable model organism for C4 grasses, closely related to bioenergy crops like switchgrass and foxtail millet.
• Advancements in genome sequencing highlight the need for robust genetic tools in Setaria viridis.
• Current limitations in performing controlled crosses hinder the genetic exploration of Setaria viridis.

Purpose of the Study:

• To develop and optimize a standardized protocol for efficient genetic crosses in Setaria viridis.
• To facilitate the rapid production of outcross progeny for genetic analysis and breeding.

Main Methods:

• A novel protocol involving heat treatment (48°C for 3-6 minutes) for emasculation of Setaria viridis (accession A10.1) panicles.
• Pruning panicles to retain 20-30 florets and labeling flowers to ensure accurate cross-pollination.
• Testing various heat treatment durations and temperatures to establish optimal conditions.

Main Results:

• The optimized heat treatment protocol allows for efficient emasculation and controlled crossing in Setaria viridis.
• A single researcher can perform at least 15 crosses per day, yielding an average of 3-5 outcross progeny per panicle.
• This results in the potential production of 45-75 outcross progeny per person daily.

Conclusions:

• The developed protocol significantly enhances the efficiency of Setaria viridis genetic crosses.
• Widespread adoption will accelerate the development of recombinant inbred lines and facilitate mutation mapping and genetic analysis.
• This method is crucial for advancing Setaria viridis as a model genetic system for C4 grasses.