An efficient in vitro regeneration protocol from cotyledon and cotyledonary node of cluster bean (Cyamopsis tetragonoloba L. Taub)

Clusterbean (Cyamopsis tetragonoloba L. Taub) is a hardy crop and considered as green gold due to galactomannan content. Healthy seeds of clusterbean genotype GG-2 were surface sterilized and placed on medium containing B5 vitamins, 3% (w/v) sucrose, and 0.8% (w/v) bacteriological grade agar. The explants (cotyledon and cotyledonary nodes) obtained from seedlings of cluster bean (GG-2) were cultured in Murashige and Skoog's (MS) and B5 media supplemented with different concentrations of growth regulators NAA, BAP and 2, 4-D. Successful shoot inductions of GG-2 were established in B5 medium supplemented with NAA (2 mg/l) + BAP (2 mg/l). The cotyledonary nodes cultured on BA showed higher shoot morphogenesis capability compared to the cotyledons. The highest overall average shoot morphogenesis percentage (34%) for GG2 genotype was observed at 20μM BA. Subsequently, in the media supplemented with BA (14.4 μM) and IAA (12.3 μM), the cotyledonary node explants of cluster bean cultivars exhibited the highest percentage of multiple shoot formation. Highest percentage (74%) of rooting of in in vitro-regenerated shoots was recorded in B5 medium containing 3 mg/l IBA, 2 mg/L BA and 1 mg/l GA₃ in the cluster bean genotype GG 2. The present regeneration system is efficient and can be used for genetic transformation studies.