Propagation of papaya (Carica papaya L.) by in vitro methods in Trinidad

In Trinidad, papaya (Carica papaya L.) is grown entirely from seedlings and the technology involved in vegetative propagation is not widely known or understood by the farming community. Consequently, studies were conducted to develop simple methods of propagating papaya in vivo, so as to provide producers with a wider choice in methods of plant production, Additionally, such techniques can enable standard varieties to be produced from the most outstanding local types; those developed through breeding programmes and from those that are parthenocarpic. The techniques utilised were chip budding, terminal wedge, and side grafting, basal application of indolebutyric acid (IBA); (3000 mg L-1) to two types of side shoot cuttings and untreated cuttings. Scions were obtained from the same 75-day-old rootstocks to be budded and (or) grafted. Side shoots in the rooting study were produced from mature trees that were decapitated. The terminal wedge method was superior over budding and side grafting. This was demonstrated by the 100% success and good growth performance in the field. Side shoots with the basal swelling (knob) treated with IBA at 3000 mg L-1 resulted in 83.3% of the cuttings rooted and the highest number of roots per cutting. However, 35% mortality was experienced post-rooting and this was attributed to transplantation shock and damage to the fragile adventitious root system. The results indicated that the terminal wedge technique could be a good candidate for commercialization of vegetative propagation of papaya.