Regeneration capacity of selected genotypes of white mustard (Sinapis alba L.)

Traditional breeding methods based on inbreeding are difficult to implement in the case of Sinapis alba (white mustard) because this plant displays high levels of self-incompatibility. More rapid progress in breeding could be possible if biotechnological methods and in vitro cultures were used. However, white mustard is not readily amenable to biotechnological treatment. Seeds of traditional S. alba cultivars (e.g., Nakielska) are characterized by high levels of glucosinolates and erucic acid. However, a new Polish variety of white mustard (Bamberka) possesses low erucic acid content in the oil. The main goal of the study was elaboration of a plant regeneration system via in vitro culture of hypocotyl and cotyledon explants from low and high erucic acid-containing white mustard cultivars. In these experiments, a simple system for in vitro regeneration of white mustard was developed, with the aim to promote maximum formation of shoots within a short period of time. Traditional and improved cultivars of S. alba showed comparable capacity for shoot development from hypocotyl-derived and cotyledon-derived explants. The two types of cultivars were characterized by essentially equivalent shoot regeneration responses, being slightly higher in hypocotyl than the cotyledonary explants. A greater influence on shoot regeneration from hypocotyl explants was observed on medium supplemented with 4.4 μmol 6-benzylaminopurine, 0.57 μmol indole-3-acetic acid, and a low concentration of kinetin (4.6 μmol). This technique will allow for rapid generation of sufficient plant material for further use in a variety of white mustard breeding projects.