The first genetic map of a synthesized allohexaploid Brassica with A, B and C genomes based on simple sequence repeat markers

Abstract

We present the first genetic map of an allohexaploid Brassica species, based on segregating microsatellite markers in a doubled haploid mapping population generated from a hybrid between two hexaploid parents. This study reports the first genetic map of trigenomic Brassica. A doubled haploid mapping population consisting of 189 lines was obtained via microspore culture from a hybrid H16-1 derived from a cross between two allohexaploid Brassica lines (7H170-1 and Y54-2). Simple sequence repeat primer pairs specific to the A genome (107), B genome (44) and C genome (109) were used to construct a genetic linkage map of the population. Twenty-seven linkage groups were resolved from 274 polymorphic loci on the A genome (109), B genome (49) and C genome (116) covering a total genetic distance of 3178.8 cM with an average distance between markers of 11.60 cM. This is the first genetic framework map for the artificially synthesized Brassica allohexaploids. The linkage groups represent the expected complement of chromosomes in the A, B and C genomes from the original diploid and tetraploid parents. This framework linkage map will be valuable for QTL analysis and future genetic improvement of a new allohexaploid Brassica species, and in improving our understanding of the genetic control of meiosis in new polyploids.

A High-Density Genetic Map of an Allohexaploid Brassica Doubled Haploid Population Reveals Quantitative Trait Loci for Pollen Viability and Fertility

“…Finally, 7,950 SNPs reached Q20 quality limits and were used for linkage map construction (Table S2). In addition, 274 SSR markers from Yang et al (2016b) were included in linkage map construction.…”

“…Genetic mapping materials were the same as described in Yang et al (2016b). Maternal line 7H170-1, derived from several generations of selfing from the cross of B. carinata x B. rapa (Tian et al, 2010), and paternal line Y54-2, generated from the cross of B. napus x B. nigra (Pradhan et al, 2010), produced an allohexaploid hybrid H16-1 from which a DH population was created by microspore culture (Geng et al, 2013).…”

“…Those markers which were unequivocally assigned to a chromosome were used to identify chromosomes A1–A10 (from the B. rapa sequence), B1–B8 (from the B. nigra sequence), and C1–C9 (from the B. oleracea sequence). Finally, 274 SSRs from the linkage map of Yang et al (2016b) were added to form a consolidated linkage map according to the genetic or physical map position of the SSRs on the genome. The twenty-seven chromosomes in the consolidated linkage map were compared with the previous linkage groups of Yang et al (2016b).…”

“…Finally, 274 SSRs from the linkage map of Yang et al (2016b) were added to form a consolidated linkage map according to the genetic or physical map position of the SSRs on the genome. The twenty-seven chromosomes in the consolidated linkage map were compared with the previous linkage groups of Yang et al (2016b). …”

“…In addition, H16-1 was one of the two most prolific hybrids in production of DH progenies by microspore culture (Geng et al, 2013). The DH population derived from hybrid H16-1 was used to create the first framework genetic map of allohexaploid Brassica based on simple sequence repeat markers (Yang et al, 2016b). …”