Medium, Explant and Genotype Factors Influencing Shoot Regeneration in Oilseed Brassica spp.

Abstract

AbstractThe effects of culture media, explants and genotypes on shoot regeneration in oilseed Brassica species were examined in this study. The maximum shoot regeneration frequency was obtained in Murashige and Skoog medium supplemented with 3 mg l−1 6‐benzylaminopurine and 0.15 mg l−1 1‐naphthaleneacetic acid. The addition of 2.5 mg l−1 AgNO3 was very beneficial to shoot regeneration in B. napus and Ag2S2O3 (10 mg l−1) was even superior to AgNO3 (2.5 mg l−1). Explant age, explant type and carbon source also significantly affected shoot regeneration. Four‐day‐old seedlings of cotyledonary explants showed the maximum shoot regeneration frequency and number of shoots per explant. Of the four explants – peduncles, hypocotyls, cotyledons and leaf petioles – cotyledons produced the highest shoot regeneration frequency (56.67 %). Four carbon sources – glucose, maltose, starch and sucrose – were compared for their respective effects on shoot regeneration from cotyledonary explants. Sucrose appeared to be the best carbon source for shoot regeneration with the highest shoot regeneration frequency (76.00 %). Considerable variation in shoot regeneration from cotyledonary explants was observed both between and within Brassica species. The shoot regeneration frequency ranged from 10.00 % for cv. R5 (B. rapa) to 83.61 % for cv. N1 (B. napus). Two B. napus, one B. carinata and one B. juncea cultivars exhibited shoot regeneration frequency higher than 70 %. In terms of the number of shoots produced per explant, B. rapa showed the highest variation, ranging from 5.64 for cv. R3 to 1.33 for cv. R5. Normal plantlets were regenerated from all induced shoots and developed normally. The regenerated plants were fertile and identical with the source plants.