Cultures of P. grisea used in this study were isolated from infected rice seeds collected from Mvomero, Kilosa
and Kilombero districts, Morogoro region, Tanzania. The germinating spores and mycelia were picked with a
slightly bent inoculating needle and transferred to the Petri dishes containing Potato Dextrose Agar (31.2 g Potato
Dextrose Agar powder and 800 ml of distilled water) at 4 equidistant points [18]. The Petri dishes were
sealed with masking tape and incubated at alternating temperatures of about 28˚C - 32˚C for five days in alternating
cycles of 12 h light and darkness to induce growth of P. grisea and were kept upside down. The pure
cultures of the isolates were grown on V8 agar (3 g Calcium Carbonate, 200 ml V-8 juice and 20 g agar in 800
ml of distilled water) for 14 days to induce sporulation. The V-8 agar was used for producing P. grisea conidia.
The petri dishes containing P. grisea inoculum were stored in the refrigerator at 5˚C [19] for further use.