VIABILITY OF COCHLIOBOLUS SATIVUS CULTURES AFTER STORAGE UNDER DIFFERENT CONDITIONS
M.I.E. Arabi, M. Jawhar, A. Al-Daoude
Different storage methods were tested to examine their usefulness in viably maintaining field isolates of Cochliobolus sativus. Fungal isolates were stored at (i) 4°C in sand, (ii) in silica gel at 4°C (iii) on potato dextrose agar (PDA) medium at 4°C, or (iv) frozen as conidia at -20°C. The cultures were assessed after 12 and 24 months of storage. Cultures of all isolates were viable after two years of storage in sand and silica gel at 4°C or dry at -20°C, whereas, isolates stored on PDA were not viable and heavy contamination with bacteria was frequently observed. After two years storage, isolates were able to infect barley leaves but sporulation was reduced dramatically, depending on the isolate and the storage method employed. AFLP analysis revealed several genetic changes between stored and non-stored isolates. A total of 444 scorable DNA bands were obtained; 324 of these (71%) were polymorphic. However, the proportion of DNA alterations varied according to the storage method.