Somatic embryogenesis and plant regeneration in cassava
1995
Narayanaswamy, T.C. | Ramaswamy, N.M. | Rangaswamy, S.R. Sree
Information on in vitro embryogenic potentiality of native cassava cultivars are limited. Therefore, investigations on in vitro culture in cassava (Manihot esculent Crantz) were carried out with the objective of inducing callus and regenerating plants from selected explants of two cultivars, Co.2 and Co.3, having high yield potential and better adaptability. The explants used were shoot tip, stem segments, axillary buds and young leaf lobes. Murashige and Skoog (MS) medium supplemented with seven levels of 2,4-D (0-6 mgl(-1)) and sucrose (2 percent) were used for callus induction. Differences were observed with respect to callus induction frequency and callus growth. Out of seven combinations of treatments tried, shoot tip and young leaf lobe of Co.2 responded better than the other explants. They recorded 100 % callus induction in two combinations having 5 and 6 mgl(-1)) of 2,4-D and in the same treatment, stem segments (44 percent) and axillary buds (58 percent) recorded lower frequency. Shoot tip and young leaf lobe of the other genotype, Co.3, have recorded maximum a 95 % 100 percent callusing frequency in the same combination. The other two explants, axillary bud and stem segments, recorded higher frequency in combinations having 6 mg 2,4-D. Among seven media combinations tried for differentiation of callus for somatic embryogenesis, shoot tip produced somatic embryoids on MS mais 2,4-D (0.01 mg/l) mais BAP (0.1 mg/l) mais GA3 (1.0 mg/l) in about 40 percent of the cultures and these later developed into shootlets. Protein Profile study of SDS-PAGE showed that specific proteins appear or disappear at different stages of calli differentiation derived from young leaf lobe and shoot tip. The results of this study indicate the possibility of regenerating many plants for further selection.
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