Evaluation of oilseed Brassica napus germplasm for days to flowering under a short-day condition and QTL mapping of the trait

• Author / Creator

  Gill, Karanjot

• Canola (Brassica napus, AACC = 2n = 38) is an important oilseed crop in Canada. Among the different agronomic traits, the earliness of flowering and maturity are important for growing this crop on the Canadian prairies. The earliness of flowering can be improved by using the genes/alleles capable of promoting flowering under a short-day condition. In the present study, a genome wide association study (GWAS) was carried out by using SNP marker data and phenotypic data of days to flowering of 184 inbred lines, derived from six B. napus × B. oleracea interspecific crosses, grown under a 10 h photoperiod condition. Three QTL affecting days to flowering under this short-day condition were identified on chromosomes C1, C5 and C9. The effect of the C9 QTL was further confirmed by designing SSR markers from this QTL region and testing the markers on this inbred population. The early flowering C9 QTL allele could also be confirmed through evaluation of a set of B. napus lines under a short-day condition (10 h photoperiod) and genotyping the lines with these SSR markers. Near-isogenic lines (NILs) were also developed in this thesis research for C1 and C9 QTL, which have been mapped previously by using a population derived from Hi-Q × RIL-144 (carrying genome contents introgressed from B. oleracea var. alboglabra). Marker-assisted backcrossing enabled the introgression of these QTL alleles in the genetic background of Hi-Q. This is also evident from phenotypic evaluation of the NILs under a 10 h photoperiod condition where the NILs carrying the C1 or C9 QTL allele of RIL-144 flowered significantly earlier than the NILs carrying the Hi-Q allele. Thus, the results from this study provided evidence for the existence of diverse and valuable alleles in the C genome of B. oleracea which can be exploited in the breeding of B. napus canola.

• Subjects / Keywords

  • Brassica napus
  • QTL mapping
  • Flowering time
  • Short day photoperiod

• Graduation date

  Spring 2021

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-3pdv-0e80

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.