Location: Forage Seed and Cereal Research Unit
Project Number: 2072-21500-001-000-D
Project Type: In-House Appropriated
Start Date: Feb 1, 2024
End Date: Jan 31, 2029
Objective:
Objective 1: Develop cover crops with increased performance and adaptability in end use environments.
• Sub-objective 1A: Improve annual ryegrass germplasm for reliable spring termination.
• Sub-objective 1B: Identify traits and develop selection strategies for improving root system architecture (RSA) in annual ryegrass for utilization as a winter cover crop.
Objective 2: Develop germplasm in cool season grass species with improved trait performance and seed yield.
• Sub-objective 2A: Develop breeding pipeline for genomic selection in perennial ryegrass and tall fescue for low temperature (LT) and high temperature (HT) tolerance traits.
• Sub-objective 2B: Determine the genetic diversity and inheritance of seed shattering and stem rust resistance in tall fescue.
Objective 3: Develop genetic, genomic, and molecular resources that can be applied to improve performance and utility of grasses in diverse environments.
• Sub-objective 3A: Develop plant transformation and gene editing tools for cool season grasses.
• Sub-objective 3B: Evaluate genomic and structural diversity in Lolium.
Approach:
This research project will develop cover crops with increased performance and adaptability in end use environments (Objective 1). In greenhouse and field experiments we will select annual ryegrass that are more susceptible and easier to terminate with glyphosate in cover crop plantings. We will work to understand the genetics of herbicide sensitivity and develop molecular markers suitable for selecting glyphosate susceptible plants. This will be accomplished through a candidate gene association study. Candidate genes will be identified from the known genes of the shikimate biosynthesis pathway and from gene expression analysis of glyphosate treated plants. We will identify traits and develop selection strategies for improving root system architecture (RSA) in annual ryegrass through greenhouse studies that optimize evaluation methods for RSA and initiate a breeding program for improved RSA.
Grasses with improved stress resilience and higher seed yield will be developed (Objective 2). This will be done by developing selection pipelines for high and low temperature tolerance using early generation high-throughput phenotyping with combined among-family and within-family selection in perennial ryegrass and tall fescue. We will determine the genetic diversity and inheritance of seed shattering and stem rust resistance in tall fescue. Accessions of tall fescue from the National Plant Germplasm System (NPGS) will be evaluated for stem rust and seed shattering in replicated field experiments, and the best plants for resistance and seed retention will be used to develop a segregating population. This population will be evaluated for resistance and shattering and then used in a genome wide association study to identify marker-trait association using genotyping-by-sequencing.
The project will develop genetic, genomic, and molecular resources that can be applied to grasses to accelerate the pace of genetic improvement (Objective 3). Plant tissue culture, agrobacterium-mediated transformation, and gene editing tools for cool season grasses will be developed through experiments with ten NPGS population. We will evaluate the difference in genomic and structural diversity between annual and Italian type ryegrass, and between wild and cultivated perennial ryegrass, using whole genome sequencing. Sequencing will use a combination of Illumina and PacBio Sequel long read sequencing to 20X coverage across multiple accession and individuals. Bioinformatics software packages will be used to assemble the genomes and identify small-scall and large-scale structural variants. Variation affecting genes related to flowering time, vernalization, and perenniality will be investigated.
