Genetic analysis of the B-genome chromosomes in the Brassica species

• Author / Creator

  Navabi, Zahra

• The family Brassicaceae includes a number of important species used as vegetables, oilseeds and medicine. The Brassica B-genome is significantly diverged from the A- and C-genomes, and species containing the B-genome possess many valuable agronomic and disease resistance traits. In this thesis, two populations of interspecific crosses between Brassica napus (AACC) and Brassica carinata (BBCC) were studied, and microsatellite (SSR) markers and genomic in situ hybridization (GISH) techniques were applied to characterize the B-genome chromosome introgressions in the advanced backcross populations and their effect on disease resistance, morphological and seed quality traits.
  A BC2S3 derived doubled haploid (DH) population was genotyped with 184 SSR markers and DH lines carrying stable B-genome chromosomal segments were identified. The GISH assay demonstrated that three of the 60 DHs were substitution lines in which the B-genome chromosome J13 was common to all. The lines with B-genome chromosomes, “B+”, were significantly different (P <0.01) from the lines without B-genome chromosomes, “B-” for some morphological and seed quality traits, such as days to flowering, days to maturity and erucic acid content. Further study revealed that resistance to Sclerotinia stem rot (caused by Sclerotinia sclerotiorum) has been inherited from the B or C genomes of B. carinata in some of the DH lines.
  Several BC3S1 families of another cross, derived from well-characterized BC3 plants containing introgressed B-genome chromosomes, were analyzed using SSR markers and the GISH assay to study the inheritance of the B-genome chromosome(s) and their association with morphological traits. This study revealed that the B-genome chromosomes tend to transfer through generations, either as whole chromosome(s) or as chromosomes without small terminal segments, as evidenced by low recombination frequencies (~ 0%) between the B and A/C-genome chromosomes. These results were supported by the GISH assay and chromosomes counts, and revealed that many of the BC3S1 lines were addition lines carrying extra B-genome chromosomes.

• Subjects / Keywords

  • Genetics, brassica species, introgression

• Graduation date

  Fall 2009

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3PM08

• 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.