IN-VITRO PLANT-REGENERATION OF MEXICAN LIME AND MANDARIN BY DIRECT ORGANOGENESIS

An efficient system for in vitro regeneration by organogenesis startin g from internodal stem segments from seedlings of Mexican lime (Citrus aurantifolia Christm, Swing.) and mandarin (C. reticulata Blanco cv. Monica) was developed, The best results were obtained when the wounded edges of internodal stem segments cut longitudinally were placed down ward on the surface of the culture medium. The optimal culture medium from both species was Murashige and Skoog with vitamins from B-5, medi um, 5% sucrose, 33.3 mu M BA and 5.4 mu M NAA. The best response was o btained when the segments were incubated at 25 +/- 2 degrees C for 21 d in darkness, followed by 29 d on a 16/8-h light/dark cycle (fluoresc ent light, 54 mu mol.m(-2).s(-1)). The best regeneration system tested allowed the attainment of adventitious shoots from 96% and 88% of the explants in Mexican lime and mandarin, respectively, In Mexican lime an average of 7.8 well-differentiated shoots per explant was obtained, and in mandarin the yield was 5.1. Rooting of 70% of the shoots was a chieved in culture medium with NAA (2.7-5.4 mu M) or IBA (2.5-4.9 mu M ), Of the rooted plants, 85% adapted well to soil conditions, Chemical names used: 6-benzylaminopurine (BA), alpha-naphthaleneacetic acid (N AA), indole-3-butyric acid (IBA).