H. Abd El-Ghany, Z. Moussa, E.A. Salem and A.F. Abd El-Rahman
الملخص الانجليزي
Soft rot is a disease affecting potato in fields, during transit and storage. This investigation aimed to apply a safe practice to minimize the losses due to this disease under storage conditions at ambient temperature. In this regard, gamma irradiation was used to extend storability through its inactivation effect on soft rot bacteria. Eight bacterial isolates were recovered on Logan’s medium from kitchen stored potato tubers with a typical symptom of soft rot disease. Five isolates were found pathogenic and identification as Pectobacterium atrosepticum and Pectobacterium carotovorum subsp. brasiliense based on colony appearance on Logan’s medium, along with morphological and bacteriological characteristics. Confirmation the identification of two isolates E2 and E4 was made by molecular methods using 16SrDNA sequences analysis. The two bacterial isolates, Pectobacterium atrosepticum and Pectobacterium carotovorum subsp. brasiliense, were irradiated by different doses of gamma irradiation. Complete inactivation occurred at doses 2.5 and 2.0 KGy for high concentration (Approximately 4.0 x109 CFU/ml) of P. atrosepticum and P. carotovorum subsp. brasiliense, respectively. The D10 value of gamma irradiation was 0.24 KGy for P. atrosepticum and 0.20 KGy for P. carotovorum subsp. brasiliense. Irradiation of artificially infected tubers with soft rot bacteria by gamma rays using the two mentioned D10 doses for these two bacterial species increased storage period of potato at ambient temperature. The effect of gamma irradiation on internal chemical quality of tubers revealed an improvement after irradiation by the two gamma irradiation doses 0.24 and 0.2 KGy, and storage under ambient temperature.
د زياد موسى عبد المعطي | Zeiad Moussa Abd El-Moati | 6673