PLANT-REGENERATION FROM STEM CORTEX EXPLANT AND PROTOPLAST CULTURES OF BRASSICA-JUNCEA (MUSTARD)

Plant regeneration from stem cortex explants of 13 genotypes of Brassica juncea was assessed. Regeneration was strongly affected by genotype, as up to 50.6 shoots were produced per 100 calli of the most responsive line (Blaze), whereas no shoots were obtained from less responsive lines (Zem1, Vniimk351). Blaze was chosen for B. juncea stem cortex protoplast isolation. After one week of culture, 11-14 % of the cells had divided, and about 0.002 % produced 1-2 mm colonies within 6 weeks. Up to 7 % of these colonies gave rise to shoots upon transfer to plant regeneration medium.