Seedling infection assay for resistance to <i>Sclerotium cepivorum</i> in <i>Allium</i> species

Abstract

Allium white rot (AWR) caused by the soilborne fungus Sclerotium cepivorum is the most devastating disease in onion crops worldwide Integrated pest management strategies involving cultural practices biocontrol agents genetic engineering and selective breeding are being investigated to control this disease A major obstacle to evaluating these different methods is the lack of a simple accurate rapid assessment technique for AWR pathogenesis An assay for quantifying AWR tissue resistance in Allium species has been developed Lesion development on Allium seedlings was used as an indicator of susceptibility to infection A difference in AWR resistance between leek and onion seedlings was detected using this assessment technique with infection scores of 13 and 5456 respectively Leek seedlings exhibited less frequent and less extensive lesions than the onion seedlings Engineered germplasm onion cultivars and other related Allium species with varying degrees of susceptibility to AWR will be screened using this assay to calibrate levels of AWR resistance