Short Communication Production and characterization of intergeneric hybrids between Brassica oleracea and a wild relative Moricandia arvensis

Intergeneric crosses were made between Brassica oleracea and Moricandia arvensis utilizing embryo rescue. Six F1 hybrid plants were generated in the cross-combination of B. oleracea · M. arvensis from 64 pods by the placenta-embryo culture technique, whereas three plants were produced in the reciprocal cross from 40 pods by the ovary culture technique. The hybrid plants were ascertained to be amphihaploid with 2n ¼ 23 chromosomes in mitosis and a meiotic chromosome association of (0–3)II + (17–23)I at metaphase I (M I). In the backcross with B. oleracea, some of these hybrids developed sesquidiploid BC1 plants with 2n ¼ 32 chromosomes that predominantly exhibited a meiotic configuration of (9II + 14I) in pollen mother cells. The following backcross of BC2 plants to B. oleracea generated 48 BC3 progeny with somatic chromosomes from 2n ¼ 19 to 2n ¼ 41. The 2n ¼ 19 plants showed a chromosomal association type of (9II + 1I) and a chromosomal distribution type of (9 1 /2 +9 1 /2) or (9 + 10) at M I and M II, respectively. These facts might suggest that they were monosomic addition lines (MALs) of B. oleracea carrying a single chromosome of M. arvensis that could offer potential for future genetic and breeding research, together with other novel hybrid progeny developed in this intergeneric hybridization.