IN VITRO REGENERATION OF ARTOCARPUS CAMANSI AND ARTOCARPUS ALTILIS

A protocol for the in vitro regeneration of Artocarpus altilis (breadfruit) and Artocarpus camansi (“chataigne,” breadnut) is outlined. Factors influencing culture establishment, production of microshoots, rooting of microcuttings and acclimatization of breadfruit, and “chataigne” plantlets are discussed. The addition of 2 g/L polyvinylpyrrolidone (PVP) significantly reduced oxidative browning of explants of both species. Aseptic cultures of mature meristem and shoot tip explants, juvenile shoot tip and nodal explants were successfully established after exposure to antibiotic and fungicide pretreatments and antibiotic medium treatments. Shoot tip and nodal seedling explants of “chataigne” were established on MS supplemented with 4.4 µM BA and mature meristem, explants of breadfruit on N5K and N15K macronutrients and MS micronutrients and vitamins with BA supplied at 4.4 µM. Shoot multiplication of both species was achieved by subculturing secondary shoot tip and nodal explants on medium which consisted of N30NH₄ macronutrients, MS micronutrients and vitamins, supplemented with zeatin 2.2 µM which was more effective than BA at this stage. IBA supplied at 10^-6 M enhanced in vitro rooting of breadnut microcuttings when compared to IAA and NAA at similar concentrations. Breadfruit microcuttings rooted on basal medium as well as on multiplication medium. Acclimatization of plantlets of both species was possible in vermiculite or jiffy pellets under humid conditions. Approximately 40% of the plantlets were successfully hardened under greenhouse conditions. The in vitro regeneration of both of these species has application for micropropagation, germplasm exchange and preservation and crop improvement.