Keywords: antioxidants, flesh colour, fruits, guava fruit, micropropagation, multiple shoots, nutrition, phenol content, plant growth regulators, plant regeneration, in vitro regeneration
Total phenol content of guava fruit and development of an in vitro regeneration protocol amenable to genetic improvement
Total soluble phenolics in two white ('Allahabad Safeda' and 'Lucknow49'), two pink ('Beaumont' and 'Gushiken Sweet'), and three red fleshed ('Ka Hua Kola', 'Ruby Supreme' and 'Red Fleshed') guava (Psidium guajava L.) fruits were assessed using the FolinCiocalteu procedure. 'Allahabad Safeda' and 'Ruby Supreme' contained the highest level of phenols (1,967.5 and 1,921.25 g/g gallic acid equivalents). No significant difference in phenolic content was observed between white and red fleshed guava fruits. An in vitro method was developed for clonal propagation of 'Lucknow49' and 'Gushiken Sweet' cultivars. Five concentrations of sixbenzylaminopurine (BAP) and kinetin (KIN) plant growth regulators were tested for in vitro regeneration. A maximum of 4.5 shoots per explant was produced on Murashige and Skoog medium supplemented with 8.9 M BAP + 9.4 M KIN. These studies indicate that guava, a rich source of natural phenolic antioxidants, can be efficiently micropropagated for genetic studies to enhance its nutraceutical value.