Clonal propagation of guava (Psidium guajava L) on nodal explants of mature elite cultivar

Guava (Psidium guajava L.) is a very valuable tropical and subtropical fruit. However, guava micro-propagation are genotypes dependent, there are several problems associated with in vitro cultures of guava including browning or blackening of culture medium due to leaching of phenolics, microbial contamination, and in vitro tissue recalcitrance. A micro-propagation system using Murashige and Skoog (MS) medium with 6-benzylaminopurine (BA), kinetin and naphthaleneacetic acid (NAA) was developed for guava (Psidium guajava L) from mature cultivar. As part of this research various disinfection methods and plant growth regulators were tested in vitro. The most effective method involved treating explants in a 15% bleach solution for 20 mins followed by culturing them in MS medium with 250 mg/L polyvinylpyrrolidone (PVP). This method maximized the percentage of bud breakage (53.3%), while producing the minimum browning rate (18.3%) for the explants. The best observed proliferation rate (71.2%) occurred on the MS medium supplemented with 4.44 μM BA, 4.65 μM kinetin (KT) and 0.54 μM NAA. It produced the highest mean number of shoots (2.2). Shoots were then rooted (65%) when dipped in 4.9 mM Indole-3-butyric acid (IBA) solution for 1 min and rooted plantlets survived (100%) after acclimatization to the greenhouse.