Identification, characteristics, and cytological analysis of three disomic alien addition lines of Brassica napus- Raphanus sativus

Alien addition lines refer to the incorporation of one or more chromosomes from a donor species into the genomic background of a recipient species. These lines serve as crucial tools in genetic engineering, particularly for transferring beneficial genes and desirable traits from a donor genome to a recipient genome. In this study, we obtained three disomic alien addition lines (DAALs) of Brassica napus-Raphanus sativus (AACC + 2R, 2n = 40) from a complete set of monosomic alien addition lines (MAALs) through microspore culture techniques, utilizing PCR amplification with R chromosome-specific primers and fluorescence in situ hybridization (FISH). We conducted a comprehensive and systematic analysis of these DAALs and their parents. Phenotypically, these lines exhibit significantly distinct characteristics compared to their parental types. The silique length of line DR5 exceeds that of lines DR2 and DR4. The DAALs also display significantly reduced silique width and beak length compared to their parental lines. Regarding pollen viability, thousand seed weight, and seeds per pod, the DAALs demonstrate superior performance relative to the MAALs. Furthermore, the seeds from line DR4 are larger than those of the parental B. napus. Cytological observations indicate that the chromosome behavior of the DAALs is regular, with 20 bivalents encompassing 10 II^A-A, 9 II^C-C, and 1 II^R-R. At anaphase I, an even distribution of chromosomes to both sides of the pollen mother cells (PMCs) is observed in the DAALs. Overall, these DAALs are anticipated to have a substantial economic and agricultural impact on the enhancement of B. napus.