Aspects of production affecting variability in vegetable crop quality

Variable quality is a major issue affecting many vegetable crops and can result in products that do not meet consumer demands. This is a direct cost to the producer. Quality attributes include ranges in size, dry matter content, appearance, taste, texture and shelf life, and there is growing demand for higher levels of health promoting compounds in vegetables. Achieving these quality attributes will be in part due to genetics, but even within a crop there is a large amount of variability in quality that can be minimised - or exploited. The key to improved profitability is ensuring more of the yield is in the desired quality ranges. Variability in size, dry matter content and other quality attributes is caused by a large range of factors, and in many cases as yield increases the variability in quality also increases. In some cases, achieving the required quality often appears to involve a trade-off with yield. In both potato and onion crops final size distribution, dry matter content and internal quality vary with genetics, crop establishment and conditions during growth, particularly nutrient and irrigation supply. This paper considers how variability in quality depends on interactions between growth factors and how site and season specific management can help to reduce variability.