Application of tissue culture to cashew (Anacardium occidentale L.) breeding: An appraisal

Summary of the previous works on the in vitro culture of cashew is highlighted with emphasis on the critical factors that influence the explants response and plantlet regeneration. The recalcitrant nature of cashew has been attributed to the limited success recorded so far in the in vitro culture of the crop and abnormal development has been reported in the calli derived from its explants.Browning of explants in cashew was found to be due to the presence of high secondary metabolites and it has been reduced through frequent transfer of explants, addition of activated charcoal and dark treatment. Explants necrosis has also been traced to the effect of strong sterilization. Meanwhile, the use of explants from in vitro germinated seedlings or fungicidal treated young flush has been found to improve the success rate significantly. The use of MS base salt supplemented with two-step treatment of cytokinins enhances the response of cashew explants and development of derived plantlets.Key words: Cashew, Invitro Culture, Breeding, Explant Browning, Growth Regulator