Radical disinfestation protocol eliminates in vitro contamination in Guava (Psidium guajava']java L.) seeds

Controlling contamination in vitro is one of the basic requirements for successful tissue culture technology. In preliminary studies, in vitro contamination of guava seeds was almost 100%, even when disinfested with bleach. To overcome this problem, we developed a unique method to control contamination using bleach and strong acids. Submerging guava seeds in 10% HCl for 24-72 h followed by a 30 min treatment with 10% bleach (NaOCl) reduced contamination rates from 98 to 0%. Substituting 5% H2SO4 for 12 h for 10% HCL gave similar results. In addition to eliminating contamination, acid-treated seeds germinated faster in vitro than control seeds germinated in a greenhouse (15 vs. 40 days, respectively).