Direct Organogenesis in Brassica juncea var. NRCDR-2 and Analysis of Genetic Uniformity Using RAPD Markers

A high frequency plant regeneration protocol has been developed in Brassica juncea var. NRCDR-2 via direct organogenesis from cotyledonary petiole explants. Cotyledonary petiole explants were procured from 5-day-old in vitro germinated seedlings and cultured on MS medium supplemented with various combinations and concentrations of cytokinins (BAP, Kn) and auxins (IAA, NAA). The highest average number of shoots per explant (6.73) was obtained on MS medium supplemented with 1.0 mg/l BAP, 0.1 mg/l NAA and 10 mg/l AgNO3 with 93.34 percent explant regeneration. The highest frequency of rooting (100 %) was obtained on MS medium supplemented with 0.3 mg/l IAA within 10-12 days of transfer to the rooting medium. Regenerated plantlets were obtained after the two months of the initiation of culture. The rooted plants were successfully acclimatized to the green house conditions. Genetic stability of in vitro regenerated plants was studied by using random amplified polymorphic DNA markers and genetic uniformity in all the regenerants was confirmed.