Facultative winter accession of Camelina sativa (L. Crantz) with early maturity contributes to understanding of the role of FLOWERING LOCUS C in camelina flowering

Camelina is being developed as a winter oilseed cover crop. Early flowering and maturity are desired traits in camelina to allow for relay planting or seeding of a summer annual following camelina harvest. Here we report that while all winter biotype accessions of camelina have a functional allele of FLOWERING LOCUS C (FLC) on chromosome 20, there are also at least 20 previously characterized spring biotype accessions that have a functional FLC allele at this locus. We observed this by analyzing 75 accessions (67 spring type, one facultative, and seven winter type) that were resequenced by Li et al., (2020) as well as 21 additional accessions for this analysis. This discovery will inform marker assisted selection efforts that are underway to increase genetic variation in the genetically narrow base of winter camelina germplasm. Furthermore, we optimized a KASP genotyping approach that effectively differentiates the presence of either the functional or subfunctional FLC allele on chromosome 20. These analyses identified a facultative winter biotype accession of camelina (PI650163-1, winter hardy with subfunctional chromosome 20 FLC allele) that has demonstrated two years of winter-hardiness and has flowered at least a week earlier than the common winter accession, Joelle. A bioinformatics approach to cytotype analysis in camelina also provided more precise categorizing of camelina accessions in the USDA-NPGS germplasm into 2n=38 and 2n=40 cytotypes. Early maturing winter-hardy camelina will reduce stress on a subsequent soybean crop and improve total cropping system yields when camelina and soybean are grown sequentially in the same season on the same land.