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 F 1 hybrid by chromosome doubling. From successive backcrosses to B. napus, MAL plants were first obtained in BC 2 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 BC 3 and BC 4 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.

Identification and evaluation of clubroot resistance of radish chromosome using a Brassica napus-Raphanus sativus monosomic addition line

“…The c-type MAL with the genetic background of rape and the clubroot resistance of radish should be useful as a bridge plant to introduce the resistance gene of radish into rape. However, it is difficult to introduce the resistance gene(s) through recombination between the c-chromosome of radish and the corresponding chromosome of rape because of the rare syndesis between these chromosomes (Akaba et al 2009). To promote the introgression of the resistance gene(s) on the c-chromosome, translocation between the c-chromosome of radish and the corresponding one of rape could be induced by γ-ray irradiation (Kaneko et al 1992).…”

“…To promote the introgression of the resistance gene(s) on the c-chromosome, translocation between the c-chromosome of radish and the corresponding one of rape could be induced by γ-ray irradiation (Kaneko et al 1992). In addition, many c-chromosome specific RAPD markers were developed in the previous study (Akaba et al 2009) that could be helpful for the development of DNA markers linked to the resistance loci.…”

“…The 9 types of autoplasmic (B. napus cytoplasm) MAL (2n = 39) with each radish chromosome were produced by the crosses of B. napus strain 'N-350' × Raphanobrassica 'Rb-63' and successive backcrossing with B. napus strain 'N-350' (Akaba et al 2009). The MAL plants were first obtained in BC 2 generation and the R. sativus-derived chromosome was identified by genomic in situ hybridization (GISH).…”

“…For these 80 plants, which included both the MAL plants (2n = 39) and the reverted plants (2n = 38), the MAL plants and the reverted plants in each type were identified by radish chromosome-specific RAPD markers according to the method of Akaba et al (2009). Four reliable markers specific to each chromosome were selected for each type from the list of Akaba et al (2009), and they were used to identify the added radish chromosome. Plants with all four specific markers for a chromosome were regarded as MAL plants, and the other plants having no specific markers were designated as the reverted plants.…”

“…In the previous study, all 9 types (a-i) of B. napus-R. sativus MALs (2n = 39) were bred through synthetic amphidiploid Raphanobrassica, Rb-63 (2n = 36, RRCC, Matsuzawa et al 1985) by successive backcrossing with Brassica napus L. strain 'N-350' (2n = 38, AACC) (Akaba et al 2009). Raphanobrassica 'Rb-63' was developed by hybridization of R. sativus L. cv.…”