Multi-environment QTL analysis delineates a major locus associated with homoeologous exchanges for water-use efficiency and seed yield in allopolyploid Brassica napus

Raman, H.; Raman, R.; Pirathiban, R.; McVittie, B.; Sharma, N.; Liu, S.; Qiu, Y.; Zhu, A.; Killian, A.; Cullis, B.; Farquhar, G.; Williams, H. S.; White, R.; Tabah, D.; Easton, A.; Zhang, Y.

doi:10.1101/2021.07.08.451711

bioRxiv · 10.1101/2021.07.08.451711

Multi-environment QTL analysis delineates a major locus associated with homoeologous exchanges for water-use efficiency and seed yield in allopolyploid Brassica napus

Raman, H.·Raman, R.·Pirathiban, R.·McVittie, B.·Sharma, N.·Liu, S.·Qiu, Y.·Zhu, A.·Killian, A.·Cullis, B.·Farquhar, G.·Williams, H. S.·White, R.·Tabah, D.·Easton, A.·Zhang, Y.

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Abstract

O_LICanola varieties exhibit discernible variation in drought avoidance and drought escape traits, suggesting its adaptation to water-deficit environments. However, the underlying mechanisms are poorly understood. C_LIO_LIA doubled haploid (DH) population was analysed to identify QTL associated with water use efficiency (WUE) related traits. Based on the resequenced parental genome data, we developed sequence-capture based markers for fine mapping. mRNA-Seq was performed to determine the expression of candidate genes underlying QTL for carbon isotope discrimination ({Delta}13C). C_LIO_LIQTL contributing to main and QTL x Environment interaction effects for {Delta}13C and for agronomic WUE were identified. One multi-trait QTL for {Delta}13C, days to flower, plant height and seed yield was identified on chromosome A09, in the vicinity of ERECTA. Interestingly, this QTL region was overlapped with a homoeologous exchange event (HE), suggesting its association with the major QTL. Transcriptome analysis revealed several differentially expressed genes between parental lines, including in HE regions. C_LIO_LIThis study provides insights into the complexity of WUE related genes in the context of canola adaptation to water-deficit conditions. Our results suggest that alleles for high {Delta}13C contribute positively to canola yield. Genetic and genomic resources developed herein could be utilised to make genetic gains for improving canola WUE. C_LI

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Raman, H., Raman, R., Pirathiban, R., McVittie, B., Sharma, N., Liu, S., Qiu, Y., Zhu, A., Killian, A., Cullis, B., Farquhar, G., Williams, H. S., White, R., Tabah, D., Easton, A., Zhang, Y.. 2021-07-10. Multi-environment QTL analysis delineates a major locus associated with homoeologous exchanges for water-use efficiency and seed yield in allopolyploid Brassica napus. https://doi.org/10.1101/2021.07.08.451711

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