Effect of gamma radiation on seed mycoflora of sunflower at different storage periods

Abstract

The effect of gamma radiation @ 0.1, 0.3, 0.5, 1.0, 1.5 and 2.0 kGy on seed mycoflora of sunflower at different storage periods (upto 3 months) was studied. A total of 16 seedborne fungi belonging to 13 genera viz., Alternaria sp., Macrophomina phaseolina, Aspergillus flavus, Aspergillus niger, Aspergillus ochraceus, Aspergillus ustus, Emericella nidulans, Fusarium sp., Epicoccum sp., Cladosporium sp., Curvularia sp., Chaetomium sp., Drechslera sp., Rhizopus sp., Trichoderma sp. and Penicillium sp. were recovered from untreated and treated seeds at different storage periods. Of the treatments used, gamma radiation at 2.0 kGy (25.56%) was found significantly superior to all other treatments followed by 1.5 kGy (40.41%) and the least effective (73.34%) was 0.1 kGy. The per cent seed infection by different seed mycoflora increased with the increase in storage period. However, there was a gradual decline in field mycoflora viz., Alternaria sp., Macrophomina phaseolina, Fusarium sp. and Drechslera sp. and gradual increase in storage mycoflora viz., Aspergillus flavus, Aspergillus niger, Cladosporium sp., Curvularia sp. etc. was found with the increase in storage period. Effect of gamma radiation on sunflower seed quality parameters was also tested and results indicated that gamma radiation can’t be used as seed treatment in sunflower.