Evaluation of brasinosteroids in the induction and generation of Ipomoea potatoes calluses

Abstract

With the purpose of studying, in different clones, the effect of two similar brassinoesteroids in the induction of callus and the regeneration of the same ones, tuberous roots belonging to the clones Cemsa 78-354, Inivit B 90-1, Inivit B 93-1, Yabú-8 and Jewel were gathered and they were placed in flasks with water in the laboratory to induce the sprouting of the buds. Later , explants of the limbo foliar were selected and they were culture in the Murashige and Skoog (1962) culture medium with 2, 4-D (0.1 mg.l-1) and 6-BAP (0.2 mg.l-1) with the similar brassinoesteroids MH-5 and Biobras-6 at different concentrations (0.001, 0.01, 0.05 and 0.1 mg.l-1) and the employment independent brassinoesteroids analogues to induce the formation of callus. Starting from the fourth week the callus were transferred, to facilitate the regenerants induction, to the culture medium previously mentioned to which the independent brassinoesteroids analogues MH-5 and Biobras-6 and cocktails with the regulators of the growth AIA (0.05 mg.l-1) and Kinetina (0.2 mg.l-1)were added . The same ones stayed under sun light conditions to temperatures of 25 ± 2 °C, relative humidity of 80-90% and luminous intensity of 3 000-5 000 l. After four weeks, it was evaluated the morphological behavior of the callus and the regenerants. Good results were obtained in the induction of morphogenic callus , when using the regulators of the independent growth in the culture medium and when being combined with 2, 4-D (0.1 mg.l-1) and 6-BAP (0.2 mg.l-1) to the concentration of 0.01 mg.l-1 with both brassinoesteroids analogues. The regenerantes induction was more favored with the employment of the brassinoesteroids analogues Biobras-6 combined with AIA (0.05 mg.l-1) and Kinetina (0.2 mg.l-1) than when being used independent in the culture medium. Key Words: culture medium, regenerantes, Sweet potato