Laboratory evaluation of sweetpotato (Ipomoea batatas) resistance to sclerotinia rot

Abstract

Sweetpotato (Ipomoea batatas) resistance to sclerotinia rot (pink rot), caused by the fungus Sclerotinia sclerotiorum, was evaluated using a laboratory technique. Excised stem lengths of four commercial sweetpotato cultivars were pierced, then inoculated with mycelial disks from S. sclerotiorum cultures. The inoculated stems were incubated in moist chambers for 48 h at 20°C and then assessed for rot severity. Of the four cultivars, ‘Toka Toka Gold’ was most susceptible to the fungus and ‘Beauregard’ most resistant. The cultivars ‘Owairaka Red’ and ‘Northland Rose’ had moderate levels of resistance. Correlations between laboratory and field results were good for ‘Toka Toka Gold’ and ‘Beauregard’. Although plant growth habit affected the disease responses of ‘Owairaka Red’ and ‘Northland Rose’, laboratory and field results for these cultivars were similar. Laboratory tests will prove useful in determining the level of disease resistance in diverse sweetpotato germplasm.

Keywords:

• sweetpotato
• Ipomoea batatas
• pink rot
• sclerotinia rot
• Sclerotinia sclerotiorum
• disease resistance
• cultivars

Notes

Deceased.