Promotion of in vitro shoot formation from shoot tip of tomato (lycopersicon esculentum mill. cv. omdurman) by ethylene inhibitors

The promotive effect of ethylene inhibitors, silver nitrate (AgNO3) and cobalt chloride (CoCl2) on in vitro shoot regeneration of tomato (Lycopersicon esculentumMill. cv. Omdurman) was investigated. Shoot development was induced on shoot tip explant cultured on MS (Murashige and Skoog, 1962) medium supplemented with kinetin (Kn) at 4.0 mg/l. Addition of CoCl2 and AgNO3 to the medium enhanced regeneration frequency as well as number of shoots obtained per explant. The best results (2.4 and 2.3) for the number of shoot per explant were obtained by using CoCl2 at 3.0 mg/L and AgNO3 at 5.0 mg/l, respectively. 100% of the in vitro induced shoots produced roots when cultured on half and full strength MS medium without growth regulators. The highest number of rooted micro shoots (22± 0.9) was obtained on half strength MS media agar-solidified and supplemented with 0.5 mg/l Naphthalene Acetic Acid (NAA). On the other hand, the longest root (7.4 ± 0.9 cm) was obtained on the same medium supplemented with 0.1 or 0.5 mg/l IBA. Rooted plants were hardened and 95% survived under greenhouse conditions.