Effect of thidiazuron (TDZ) on in vitro regeneration of blackgram (Vigna mungo L.) embryonic axes

Regeneration has been achieved in blackgram (Vigna mungo) using thidiazuron (TDZ) in the culture medium. The explanted cotyledon with wounded embryonic axes produced the highest number (9.75–10.45) of healthy, elongated shoots when cultured on shoot bud regeneration medium (SRI) composed of 2 μM BAP, 2 μM KIN, 2 μM TDZ, and 0.5 μM NAA followed by multiple shoot regeneration (SRII) medium containing 2 μM BAP, 2 μM KIN, and multiple shoot elongation (SE) medium (0.5 μM of BAP + 0.5 μM of KIN). The presence of TDZ in combination with BAP and NAA in the SRI medium for one sub-culture cycle (10–14 days) significantly increases formation of multiple shoot buds per explant. Independent, healthy shoots obtained were selected for both in vitro rooting and grafting. Establishment of plantlets in the soil was highest (80–100%) in the case of in vitro rooted compared to grafted shoots (40%). The protocol appears to be competent to Agrobacterium-meditated transformation with ‘gus’ as a reporter gene. PCR analysis of the T₀ and T₁ progenies showed the presence and transmission of the transgene. We document here the regeneration and transformation of blackgram using cotyledons with wounded embryonic axes and the protocol appears to be suitable for genetic transformation of blackgram.