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Genomic Science Program

2013 Awardee

Genetic Control of Flowering in Switchgrass

INVESTIGATORS: Yiwei Jiang, Michael D. Casler

INSTITUTIONS:Purdue University, USDA-ARS, Dairy Forage Research Center

NON-TECHNICAL SUMMARY:Flowering can negatively affect biomass yield of switchgrass. In temperate regions of the USA, flowering occurs in switchgrass around the time of peak biomass yield (about 5 to 8 weeks prior to killing frost), effectively reducing the length of the growing season. The use of late-flowering switchgrass genotypes has proven an effective mechanism to increase biomass production in the northern USA. Southern populations (lowland ecotypes) of swtichgrass can be 4–6 weeks later in flowering time than upland types, and selection of late flowering genotypes, with southern origin but under northern conditions, can extend vegetative growth. Late-flowering and winter hardy cultivars can generate up to a 50% increase in biomass yield in the northern USA. To develop a rational strategy for creating improved switchgrass with late flowering, it would be beneficial to have a better understanding of the genes that control flowering time in switchgrass. The goal of this project is to elucidate genetic mechanisms of flowering time in switchgrass and identify genes controlling flowering time. Knowledge generated from the research efforts will aid breeding programs in developing late flowering varieties of switchgrass that fully utilize the growing season as well as achieve high biomass yield.

OBJECTIVES: 1) Conduct a genome-wide association analysis of flowering time in both lowland and upland panels and identify genes that control flowering time; 2) Validate genes associated with flowering time in segregating populations using linkage mapping; and 3) Examine transcriptome profiles of flowering with contrasting genotypes using RNA sequencing.

APPROACH: Building upon current genetic and genomic resources in switchgrass, the project will explore genetic control of flowering time in switchgrass by integrating genome-wide association, linkage mapping and transcriptomic analyses. We will obtain phenotypes of flowering time in the northern panel (~520 genotypes) and southern panel (~480 genotypes) and 1.2 million single nucleotide polymorphisms (SNPs) through ongoing collaborations. Genome-wide associations of SNPs with flowering time will be analyzed using a mixed model. This will allow us to identify genes that are most likely associated with flowering time. Crosses derived from both lowland and upland parental materials varying in flowering times are being developed; and flowering times of multiple segregating populations will be screened in the field sites. Candidate flowering genes will be validated in the segregating populations through linkage mapping. Approximately 10 genotypes with a range in flowering time will be chosen for transcriptome profiling by RNA sequencing.

Name: Yiwei Jiang
Fax: 765-496-2926



Plant Feedstock Genomics for Bioenergy[01/18]

Basic Research Opportunities in Genomic Science to Advance the Production of Biofuels and Bioproducts from Plant Biomass White Paper [6/15]

Lignocellulosic Biomass for Advanced Biofuels and Bioproducts: Workshop Report [2/15]

Sustainable Bioenergy [05/14]

USDA/DOE Plant Feedstocks Genomics for Bioenergy Program: Project Director / Principal Investigator Meeting [01/14]

Switchgrass Research Group: Progress Report [1/12]