Production and characterization of Brassica napus-Raphanus sativus monosomic addition lines mediated by the synthetic amphidiploid "Raphanobrassica"

Abstract

In order to breed Brassica napus-Raphanus sativus monosomic addition lines (MALs), hybridizations between two synthetic amphidiploid (RRAA and RRCC) and B. napus (AACC) were performed. Two allooctoploids (RRAAAACC and AACCRRCC) were produced from each F1 hybrid by chromosome doubling. From successive backcrosses to B. napus, MAL plants were first obtained in BC2 generation and the R. sativus-derived chromosome was identified by genomic in situ hybridization (GISH). The nine chromosomes of R-genome in the MAL plants were clearly classified by each chromosome-specific RAPD markers. As a result, alloplasmic (radish cytoplasm) B. napus-R. sativus MAL having 8 types (a-i, except for h-type) and autoplasmic (rape cytoplasm) MAL with complete 9 types (a-i) were obtained in BC3 and BC4 generations. These alloplasmic and autoplasmic MAL plants were showed differences in their morphological, physiological and cytogenetical characters. From the survey of favorable traits, it was suggested that the a-type had fertility restoring gene(s) for male sterility in alloplasmic line and the g-type had a gene controlling white color petal. These two MALs are useful materials for exploring agronomic traits located on each chromosome of radish and for promoting the introgression of promising radish gene(s) to B. napus.