Dr Bai Zetao1, Dr Harsh Raman1, Dr Rosy Raman2, Mr Brett McVittie2, Dr Xie Meili1, Dr Yuanyuan Zhang1, Dr Shengyi Liu1
1Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China,
2NSW Department of Primary Industries, WAGGA WAGGA, Australia
Flowering time is a complex trait that determines plant fitness and agronomic performance (productivity) of canola to its local growing environment. Understanding the genetic architecture of flowering time is therefore important for improving canola yield as well as understanding the evolution of divergent ecotypes (spring, semi-winter and winter types). To reveal the genetic architecture of flowering time trait, a genome wide association study (GWAS) was performed using two diversity panels representing Australian Brassica napus homozygous diversity lines (n = 326) and Chinese diversity lines (n = 324). Each GWAS panel was assessed for flowering time in separate experiments (Australia: 4 environments, China: 3 environments). To identify causal variants for flowering time, both GWAS panels of 650 lines were genotyped using Illumina sequencing (~7 to 90× coverage), and over two million high quality SNP markers were used for genome-wide association analysis (GWA). We found extensive variation in flowering time among accessions, ranging from 30 to 140 days. Accounting both population structure and kinship matrices, GWA identified 1,312 and 1,175 SNP marker loci that show significant association with flowering time, estimated in Australian and Chinese environments, respectively. At least, 10 consistent loci were identified on A02, A05, A07, A10, C01, C02, C03, and C04 chromosomes across multiple environments and countries. We identified several orthologues of Arabidopsis thaliana flowering genes, including FLOWERING LOCUS C and FLOWERING LOCUS T on the B. napus cv. Darmor-bzh genome. Data on structural and functional variants underlying flowering time genes will be presented.
Dr Harsh Raman is a Senior Principal Research Scientist at the Wagga Wagga Agricultural Institute, NSW Department of Primary Industries, Wagga Wagga. He joined the NSW DPI in 1996 and led plant genetics and pre-breeding research in wheat, barley and canola. He has published over 120 peer-refereed papers in national and international journals.