The experiment was conducted to develop a suitable protocol for high frequency plant regeneration of wild eggplant (Solanum sisymbriifolium) in order to produce a large number of rootstocks for tomato grafting for the management of wilt disease. To obtain in vitro seedlings of S. sisymbriifolium, seeds were treated with various concentrations of GA3 (Gibberellic acid) prior to place them in germination media (½ strength MS) and 750 mg/L GA3 was found as a suitable concentration resulting the highest (76.67%) germination rate. Various factors namely combination of plant growth regulators, explant types and explant age were investigated for development of an efficient plant regeneration system of S. sisymbriifolium. Cotyledon and hypocotyl explants of S. sisymbriifolium were cultured on MS medium supplemented with various concentrations of BA (6-Benzylaminopurine), NAA (α-Naphthalene acetic acid) and 2,4-D (2,4-Dichlorophenoxy acetic acid), to determine suitable medium for callus and shoot initiation. Fourteen days old cotyledon explants were found more responsive than that of hypocotyl, both in callus and shoot induction. The highest callus initiation (100%) and shoot regeneration (73.33%) were observed in MS media supplemented with 0.5 mg/L NAA + 1.0 mg/L BA and 0.2 mg/L NAA + 3.0 mg/L BA, respectively. MS medium supplemented with 0.1 mg/L NAA showed the highest frequency (86.67%) of rooting. The regenerated plantlets were acclimatized in pot soil and eventually used as rootstock for tomato (Solanum lycopersicum cv. BARI hybrid 4) grafting. The grafted plants showed no wilt disease in field condition until maturity.
Key words: Wild eggplant, rootstock, tomato, wilt disease, grafting, organogenesis
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