Studies On The Biochemical And Molecular Markers For Papaya (Carica Papaya L.) Sexuality

Differences among female, male and hermaphrodite papaya were studied through isozyme, SDS-PAGE of protein and RAPD of genomic DNA. The possibility to apply these methods in the sex identification of papaya was also discussed. The main results were as follows:1.Female, male and hermaphrodite plants were different in zymograms of peroxidase isozyme, esterase isozyme and polyphenol oxidase isozyme. Generally, the enzyme activities of female plants were higher than those of both male and hermaphrodite plants. Band with Rf=0.29 of POD isozyme appeared in the petiole of male plants and specific band with Rf=0.75 of EST isozyme appeared in mature leaf of male plants, and they both didn抰 appear in the counterparts of female or hermaphrodite plants. Therefore they could provide reference for the sex identification. The band with Rf=O.75 of PPO isozyme didn抰 exist specifically in the mature leaves of male plants, which could also be the marker in sex identification of papaya.2.SDS-PAGE diagram of protein were different among different sexual papaya, and 1 8.2KD specific protein only appeared in mature leaves of male plants.3.Among the 100 l0-bp primers, 29 primers didn抰 amplify any products in papaya, and the other 71 primers produced 345 bands among which amplified products of 69 primers had no polymorphism. The above results suggested that genetic differences among female, male and hermaphrodite plants were not significant. Only the products of primer S357 and primer S253 had polymorphism among different sexual papaya plants. Primer S357 and S253 amplified a 504bp band and a 386bp band in female papaya respectively.4.Isozyme, protein and RAPD marker could be used in the sexidentification of papaya, among which protein and RAPD marker were more usefi?than isozyme.To isozyme, the esterase isozyme and polyphenol oxidase isozyme were more effective than peroxidase isozyme in the sex identification.