Micropropagation of Avocado (<i>Persea Americana</i> Mill.)

Abstract

Avocado is a high demand, high value tropical fruit recognised for its nutritional value. Being planted as a grafted tree, propagation of avocado refers to propagation of rootstock cultivar, then graft it with bud-wood from a mature scion cultivar. Elite cultivar propagation is critical to maintain the quality of fruit and farm management practices. Avocado propagation through seeds exhibit high genetic variation, hence less appealing for orchard plantings. Rooting of cuttings is only possible through a complex, lengthy and expensive process called “ Frolich and Platt method ” . This creates limitations on rapid industry expansion due to scarcity and high price of plants in many countries. Alternative propagation methods are sought over 5 decades. Potential of micropropagation has been well demonstrated for wide variety of economically important plants. Commercial application of micropropagation for avocado will undoubtedly boost the industry around the globe. In this review, we present the developments in micropropagation of recalcitrant species, avocado, over the last 45 years. We summarise the culture media composition, hormones, growth conditions for different stages of avocado micropropagation pipeline, elaborating on cultivar specificity for in vitro success, and problems encountered under in vitro conditions and during acclimatisation. Overview of the current knowledge is critical to focus on important aspects in protocol optimisation, to develop an efficient and effective micropropagation system for avocado as well as other woody plant species recalcitrant for micropropagation.