Management of potato soft rot by gamma irradiation

الملخص EN

This investigation aims to apply a safe practice to minimize potato losses due to soft rot disease of tubers kept under ambient temperature.

In this regard, gamma irradiation was used to extend keeping quality through its effect on soft rot bacteria.

Eight bacterial isolates were recovered on Logan’s medium from kitchen kept tubers with symptoms of soft rot disease.

Five isolates were found pathogenic and tentatively identified as Pectobacterium atrosepticum and Pectobacterium carotovorum subsp.

brasiliense on the basis of the usual bacteriological methods.

A molecular method using 16SrDNA sequence analysis for verification of the identity of two isolates was made.

The two bacterial isolates, Pectobacterium atrosepticum and Pectobacterium carotovorum subsp.

brasiliense, were irradiated by different doses of gamma rays.

Complete inhibition occurred at doses 2.5 and 2.0 KGy for high densities (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 using the two mentioned D10 doses for the two bacterial species increased the shelf life of tubers kept under ambient temperature.

The internal chemical quality of tubers was shown to be improved by keeping the tubers under ambient temperature after irradiation by the two D10 doses 0.24 and 0.20 KGy.