Location: Weed and Insect Biology Research
Title: A novel strategy to map a locus associated with flowering time in canola (Brassica napus L.)Author
LONG, YUNMING - North Dakota State University | |
ZHENG, PUYING - North Dakota State University | |
Anderson, James | |
Horvath, David | |
Sthapit Kandel, Jinita | |
LI, XUEHUI - North Dakota State University | |
RAHMAN, MUKHLESUR - North Dakota State University | |
Chao, Wun |
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 10/1/2024 Publication Date: 10/8/2024 Citation: Long, Y., Zheng, P., Anderson, J.V., Horvath, D.P., Sthapit Kandel, J., Li, X., Rahman, M., Chao, W.S. 2024. A novel strategy to map a locus associated with flowering time in canola (Brassica napus L.). Theoretical and Applied Genetics. https://doi.org/10.1007/s00438-024-02191-w. DOI: https://doi.org/10.1007/s00438-024-02191-w Interpretive Summary: Gene mapping is one method used to locate genes linked to crop traits. A novel strategy was developed and used to map the chromosome location associated with flowering time (days to first open flower) in canola (Brassica napus L.). The flowering time location was mapped to a 1 mega-bases (Mb) region of chromosome A10 originating from cv 'Surpass 400'. Within this region, we identified five genes known to be involved in flowering time in Arabidopsis. These genes are thus likely candidates for the differences observed in flowering time of canola and should assist breeders to develop new canola cultivars. Technical Abstract: Flowering time has important effects on plant fitness and crop yield, and plants have evolved systems to control their seasonal rhythms in the reproductive phenology via internal circadian clock and environmental signals. Using canola (Brassica napus L.) cultivar ‘Westar’ as the recurrent parent and canola cultivar ‘Surpass 400’ as the donor parent, a chromosome segment substitution line (CSSL) was generated by molecular marker-assisted selection. This CSSL contains an introgressed 4.6 mega-bases (Mb) chromosome A10 segment (between 13 and 17.6 Mb) of Surpass 400. CSSL delayed flowering substantially compared with Westar. To map the flowering time gene, eight introgression lines (ILs) were developed carrying a series of different lengths of introgressed chromosome A10 segments using five co-dominant polymorphic markers located at 13.5, 14.0, 14.5, 15.0, 15.5, and 16.0 Mb. Eight ILs were crossed with Westar reciprocally. The resultant 16 F1 hybrids along with their parents were planted in the greenhouse for two years (2021 and 2022) to determine flowering time. Four IL lines (IL005, IL017, IL035, and IL013) showed delayed flowering compared to Westar (P < 0.0001), and their reciprocal crosses displayed a phenotype that is an intermediate in flowering time between the phenotypes of both homozygote parents. These results indicated that flowering time is partial or incomplete dominance, and we have mapped the flowering time locus within 1 Mb region between two co-dominant polymorphic markers at 14.5 - 15.5 Mb in chromosome A10. The flowering time locus was further delineated to be between 14.60 and 15.5 Mb based on the genotypic data at the crossover site, and five candidate genes identified in this region have previously been associated with flowering time in canola and/or Arabidopsis. |