Investi gati on of Measures to Control Epiphytes and Endophytes Present in Nodal Explants of Persea Americana Mill in Its in Vitro Establishment

Abstract

Signifi cant advancements in micropropagati on methods facilitate the commercial culti vati on of avocado (Persea americana Mill), a remarkable tropical and sub-tropical fruit, highly recommended for its nutriti onal value. Since high quality, true-to-type planti ng materials are required to promote the commercial producti on of avocado, this study was conducted with the objecti ve of investi gati ng an eff ecti ve sterilizati on method to control both epiphytes and endophytes present in nodal explants of P. americana cv. ‘Pollock’ to opti mize in vitro establishment measures which will lead to popularize its micropropagati on. In this study, nodal segments of approximately 10 cm from soft wood stem cutti ngs of P. americana cv ‘Pollock’ were used to obtain explants. The eff ects of 10%, 20%, and 30% concentrati ons of sodium hypochlorite (NaOCl) were evaluated, with exposure durati ons of 10 and 20 minutes, to determine their effi cacy in eliminati ng epiphytes during vitro establishment. Additi onally, the nodal explants were treated with 100 mg/L Augmenti n™ for 20 - minutes and 30 - minutes periods respecti vely, as a fi nal dip before culturing to eradicate endophytes. The eff ects of three diff erent culture media, half-strength Murashige and Skoog (MS) medium, Woody Plant Medium (WPM), and Gamborg’s medium (B5) were also investi gated. The highest survival rate (83%) of nodal segments was achieved when explants were sterilized with 20% Na- OCl for 20 minutes, followed by a fi nal sterilizati on step involving a 30-minute dip in Augmenti n™, and subsequently cultured in WPM medium.