Diverse regulatory factors associate with flowering time and yield responses in winter-type Brassica napus

Abstract

BackgroundFlowering time, plant height and seed yield are strongly influenced by climatic and day-length adaptation in crop plants. To investigate these traits under highly diverse field conditions in the important oilseed crop Brassica napus, we performed a genome-wide association study using data from diverse agroecological environments spanning three continents.MethodsA total of 158 European winter-type B.napus inbred lines were genotyped with 21,623 unique, single-locus single-nucleotide polymorphism (SNP) markers using the Brassica 60 K-SNP Illumina® Infinium consortium array. Phenotypic associations were calculated in the panel over the years 2010–2012 for flowering time, plant height and seed yield in 5 highly diverse locations in Germany, China and Chile, adding up to 11 diverse environments in total.ResultsWe identified 101 genome regions associating with the onset of flowering, 69 with plant height, 36 with seed yield and 68 cross-trait regions with potential adaptive value. Within these regions, B.napus orthologs for a number of candidate adaptation genes were detected, including central circadian clock components like CIRCADIAN CLOCK- ASSOCIATED 1 (Bna.CCA1) and the important flowering-time regulators FLOWERING LOCUS T (Bna.FT) and FRUITFUL (Bna.FUL).DiscussionGene ontology (GO) enrichment analysis of candidate regions suggested that selection of genes involved in post-transcriptional and epigenetic regulation of flowering time may play a potential role in adaptation of B. napus to highly divergent environments. The classical flowering time regulators Bna.FLC and Bna.CO were not found among the candidate regions, although both show functional variation. Allelic effects were additive for plant height and yield, but not for flowering time. The scarcity of positive minor alleles for yield in this breeding pool points to a lack of diversity for adaptation that could restrict yield gain in the face of environmental change.ConclusionsOur study provides a valuable framework to further improve the adaptability and yield stability of this recent allopolyploid crop under changing environments. The results suggest that flowering time regulation within an adapted B. napus breeding pool is driven by a high number of small modulating processes rather than major transcription factors like Bna.CO. In contrast, yield regulation appears highly parallel, therefore yield could be increased by pyramiding positively associated haplotypes.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-1950-1) contains supplementary material, which is available to authorized users.

GWAS hints at pleiotropic roles forFLOWERING LOCUS Tin flowering time and yield-related traits in canola

“…Our results showed that grouping for both spring and winter types based on FT paralogs was not that distinct (Fig. 10) suggesting that other key flowering genes such as FLC and FRI may have contributed to diversification of these morphotypes (Schiessl et al , 2017; Schiessl et al , 2015).…”

“…In addition, flowering is also affected by other external factors such as ambient temperature, insect-pests, pathogens, light quality, and abiotic stress, and some of these integrate with the flowering pathways. Genetic analyses based on classical linkage mapping (quantitative trait loci: QTL) and genome-wide association studies (GWAS) have revealed that flowering time in canola is a multi-genic trait (Ferreira et al , 1995; Long et al , 2007; Nelson et al , 2014; Raman et al , 2016b; Raman et al , 2013; Raman et al , 2016c; Schiessl et al , 2015; Xu et al , 2016; Yi et al , 2018). Candidate genes underlying flowering time variation due to vernalisation have been identified in B. napus (Fletcher et al , 2015; Hou et al , 2012; Raman et al , 2016b; Raman et al , 2013; Tadege et al , 2001; Wang et al , 2011; Zou et al , 2012).…”

Dissection of Year Related Climatic Variables and Their Effect on Winter Rapeseed (Brassica Napus L.) Development and Yield

“…On the other hand, mutations in genes involved in the flowering time control can affect seed yield components [65]. The selection of the genes involved in the flowering time regulation may play a potential role in the adaptation of rapeseed to highly divergent environments [66]. Future cultivar selection should also consider the crop phenology and influence of the environment [67].…”

Oilseed rape: learning about ancient and recent polyploid evolution from a recent crop species

“…Dalton-Morgan et al 2014). These arrays comprise an extremely valuable resource for the genetics and breeding communities in Brassica, and have already been used for applications such as linkage mapping of agricultural traits for flowering time, plant height, seed yield, germination, seedling emergence and disease resistance Schiessl et al 2015), tracking allele inheritance in interspecific hybrid populations (Mason et al 2014a(Mason et al ,b, 2015a and species identification in germplasm collections (Mason et al 2015b). SNP arrays are fast, highly reproducible and produce easy-to-analyse data (Hayward et al 2012).…”