Regulation of sex expression and flowering in papaya (Carica papaya)

Abstract

Sex expression in dioecious species such as Carica papaya is result of genetic constitution of individual and is determined genetically. However, it is subjected to be influenced by the various environmental factors including temperature and plant growth regulators (PGRs). The sex reversal in papaya is encouraged due to application of ethrel (2-chloroethylphosphonic acid) and chlorflurenol (2-chloro-9-hydroxy-9H-fluorene-9-carboxylic acid) at different doses and it was reported that not only sex expression in this species was under the control of hormonal influence but the genetically male flower primordia transformed into female ones and behaved completely into female flower and developed into fruit. Application of ethephon, NAA, CCC, and TIBA in Carica papaya at various doses reported that the sexual character of the plant become more female and resulted in a higher female:male ratio, whereas use of maleic hydrazide (MH) and gibberellic acid (GA3) at different doses enhanced maleness.