title: Analysis of B-genome chromosome introgression in interspecific hybrids of Brassica napus × B. carinata.
abstract: Brassica carinata, an allotetraploid with B and C genomes, has a number of traits that would be valuable to introgress into B. napus. Interspecific hybrids were created between B. carinata (BBCC) and B. napus (AACC), using an advanced backcross approach to identify and introgress traits of agronomic interest from the B. carinata genome and to study the genetic changes that occur during the introgression process. We mapped the B and C genomes of B. carinata with SSR markers and observed their introgression into B. napus through a number of backcross generations, focusing on a BC(3) and BC(3)S(1) sibling family. There was close colinearity between the C genomes of B. carinata and B. napus and we provide evidence that B. carinata C chromosomes pair and recombine normally with those of B. napus, suggesting that similar to other Brassica allotetraploids no major chromosomal rearrangements have taken place since the formation of B. carinata. There was no evidence of introgression of the B chromosomes into the A or C chromosomes of B. napus; instead they were inherited as whole linkage groups with the occasional loss of terminal segments and several of the B-genome chromosomes were retained across generations. Several BC(3)S(1) families were analyzed using SSR markers, genomic in situ hybridization (GISH) assays, and chromosome counts to study the inheritance of the B-genome chromosome(s) and their association with morphological traits. Our work provides an analysis of the behavior of chromosomes in an interspecific cross and reinforces the challenges of introgressing novel traits into crop plants.
authors.affiliation: Agriculture and Agri-Food Canada, Saskatoon, Saskatchewan S7N 0X2, Canada.
authors.forename: Zahra K
authors.initials: ZK
authors.lastname: Navabi
authors.forename: Kiersten E
authors.initials: KE
authors.lastname: Stead
authors.forename: J Chris
authors.initials: JC
authors.lastname: Pires
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Xiong
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Sharpe
authors.forename: Isobel A P
authors.initials: IA
authors.lastname: Parkin
authors.forename: M Habibur
authors.initials: MH
authors.lastname: Rahman
authors.forename: Allen G
authors.initials: AG
authors.lastname: Good
mesh_terms: D001937:Brassica / Q000166:cytology* / Q000235:genetics; D029688:Brassica napus / Q000166:cytology* / Q000235:genetics; D002678:Chimera / Q000235:genetics*; D008040:Genetic Linkage; D018745:Genome, Plant / Q000235:genetics*; D006824:Hybridization, Genetic / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D018598:Minisatellite Repeats / Q000235:genetics; D011123:Polyploidy