Intersubgenomic Heterosis in Rapeseed Production with a Partial New-Typed Brassica napus Containing Subgenome Ar from B. rapa and Cc from Brassica carinata
- Maoteng Li,
- Xin Chen and
- Jinling Meng *
A breeding strategy for utilizing intersubgenomic heterosis in rapeseed (Brassica spp.) was proposed by partially replacing the An and Cn subgenomes of B. napus L. (AnAnCnCn) with the Ar subgenome of B. rapa L. (ArAr) and Cc of B. carinata A. Braun (BcBcCcCc), respectively. To replace the subgenomes of natural B. napus (AnAnCnCn), pentaploid hybrids were first produced by mating the synthetic hexaploid (ArArBcBcCcCc) with natural B. napus Progenies of pentaploid hybrids were considered as the partial new-typed B. napus (ArArCcCc) since they contained 38 chromosomes and half of their genome was introgressed from Ar/Cc subgenome based on cytological and molecular assay. Most individuals of the partial new-typed B. napus showed normal meiotic behavior, high portion of germinated-pollen and good seed set. Intersubgenomic hybrids were produced by crossing cultivars of natural B. napus with the partial new-typed B. napus plants selected from F3, F4, and F5 generations. Seed yield potential of intersubgenomic hybrids was tested for three successive years and most hybrids showed strong over-control or midparent heterosis. Seed yield of hybrids was positively correlated with the genomic proportion of Ar, Cc and Ar + Cc in the new-typed B. napus It is suggested that increasing the subgenomic portion of Ar/Cc in the new-typed B. napus might further strengthen the intersubgenomic heterosis for seed yield.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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