Skin characteristics and quality of onion cultivars given different nitrogen and irrigation treatments

Abstract

SummarySkin quality of onions from commercial sources and experiments was assessed using a rotating drum to simulate handling damage. Differences in skin quality between cultivars were of greater significance than those induced by manipulating nitrogen and water supply. The drum test discriminated between samples and may be valuable for comparing varieties and indicating those appropriate for commercial use. Skin splitting and cracking decreased with an increase in numbers of skins per bulb, skin thickness and, more particularly, skin specific dry weight (the amount of plant structure per unit area of skin). Strength and stiffness of skins were less well associated with resistance to fracture and skin loss. There was no relationship with skin moisture content. Some characteristics, particularly stiffness and moisture content, varied with skin position. Inner skins contained more moisture and were more flexible. Breeding for improved skin quality through increased numbers and using specific skin weight as a primary screen appears to provide the best strategy for improvement.