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

Schiessl S, Iniguez-Luy F, Qian W, Snowdon RJ - BMC Genomics (2015)

Bottom Line: 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.In contrast, yield regulation appears highly parallel, therefore yield could be increased by pyramiding positively associated haplotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany. sarah-veronica.schiessl@agrar.uni-giessen.de.

ABSTRACT

Background: Flowering 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.

Methods: A 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.

Results: We 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).

Discussion: Gene 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.

Conclusions: Our 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.

No MeSH data available.


Related in: MedlinePlus

Climate data for all environments tested. The graphs show mean values (daylength, temperature) and monthly sums (precipitation) for each location (daylength) and each environment (temperature, precipitation). The environments are abbreviated as follows: Germany: Giessen (GI), Gross Gerau (GG), Rauischholzhausen (RH); Chile: Temuco (TE); China: Beibei, Chongqing (BB), with their respective year of harvest. For precipitation, consecutive years are placed consecutively beneath each other
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Fig2: Climate data for all environments tested. The graphs show mean values (daylength, temperature) and monthly sums (precipitation) for each location (daylength) and each environment (temperature, precipitation). The environments are abbreviated as follows: Germany: Giessen (GI), Gross Gerau (GG), Rauischholzhausen (RH); Chile: Temuco (TE); China: Beibei, Chongqing (BB), with their respective year of harvest. For precipitation, consecutive years are placed consecutively beneath each other

Mentions: The beginning of flowering (BOF) varied considerably among years and locations, spanning over a range of 97 days from 157 days after sowing (DAS) in Temuco (Chile), 2012, to 254 DAS in Rauischholzhausen (Germany) 2010. The order of flowering locations for earliest to latest flowering was Temuco (Chile)/Beibei (China)/Gross Gerau/Rauischholzhausen/Giessen (all Germany), whereby the difference was not significant between Giessen and Rauischholzhausen in 2011 (see Fig. 1, Table 1). Although this order was retained during the years 2010–2012, absolute flowering time values of each location also varied significantly between years, reflecting clearly different climatic conditions regarding, temperature and precipitation from 2010 to 2012 and varying day length between the locations (see Fig. 2). Correlations of flowering time between locations show that flowering behaviour was most similar between Gross Gerau and Rauischholzhausen, and most divergent between Giessen and Temuco. This most probably reflects differences in precipitation and day length (Fig. 2). Plant height and seed yield were recorded in all of the German environments, while plant height was also recorded in Temuco. Correlations between flowering time and plant height were always significantly positive (p = 0.05) with the exception of Temuco 2012, which was positive, but not significant. Correlations between flowering time and seed yield were negative (with the exception of Giessen 2011) and significantly so for Gross Gerau (all years) and Rauischholzhausen 2012. Correlations between plant height and yield showed no trend and were not significant (correlations see Additional file 1: Table S1).Fig. 1


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

Schiessl S, Iniguez-Luy F, Qian W, Snowdon RJ - BMC Genomics (2015)

Climate data for all environments tested. The graphs show mean values (daylength, temperature) and monthly sums (precipitation) for each location (daylength) and each environment (temperature, precipitation). The environments are abbreviated as follows: Germany: Giessen (GI), Gross Gerau (GG), Rauischholzhausen (RH); Chile: Temuco (TE); China: Beibei, Chongqing (BB), with their respective year of harvest. For precipitation, consecutive years are placed consecutively beneath each other
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4589123&req=5

Fig2: Climate data for all environments tested. The graphs show mean values (daylength, temperature) and monthly sums (precipitation) for each location (daylength) and each environment (temperature, precipitation). The environments are abbreviated as follows: Germany: Giessen (GI), Gross Gerau (GG), Rauischholzhausen (RH); Chile: Temuco (TE); China: Beibei, Chongqing (BB), with their respective year of harvest. For precipitation, consecutive years are placed consecutively beneath each other
Mentions: The beginning of flowering (BOF) varied considerably among years and locations, spanning over a range of 97 days from 157 days after sowing (DAS) in Temuco (Chile), 2012, to 254 DAS in Rauischholzhausen (Germany) 2010. The order of flowering locations for earliest to latest flowering was Temuco (Chile)/Beibei (China)/Gross Gerau/Rauischholzhausen/Giessen (all Germany), whereby the difference was not significant between Giessen and Rauischholzhausen in 2011 (see Fig. 1, Table 1). Although this order was retained during the years 2010–2012, absolute flowering time values of each location also varied significantly between years, reflecting clearly different climatic conditions regarding, temperature and precipitation from 2010 to 2012 and varying day length between the locations (see Fig. 2). Correlations of flowering time between locations show that flowering behaviour was most similar between Gross Gerau and Rauischholzhausen, and most divergent between Giessen and Temuco. This most probably reflects differences in precipitation and day length (Fig. 2). Plant height and seed yield were recorded in all of the German environments, while plant height was also recorded in Temuco. Correlations between flowering time and plant height were always significantly positive (p = 0.05) with the exception of Temuco 2012, which was positive, but not significant. Correlations between flowering time and seed yield were negative (with the exception of Giessen 2011) and significantly so for Gross Gerau (all years) and Rauischholzhausen 2012. Correlations between plant height and yield showed no trend and were not significant (correlations see Additional file 1: Table S1).Fig. 1

Bottom Line: 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.In contrast, yield regulation appears highly parallel, therefore yield could be increased by pyramiding positively associated haplotypes.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany. sarah-veronica.schiessl@agrar.uni-giessen.de.

ABSTRACT

Background: Flowering 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.

Methods: A 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.

Results: We 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).

Discussion: Gene 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.

Conclusions: Our 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.

No MeSH data available.


Related in: MedlinePlus