PHYSIOLOGICAL-MECHANISMS ASSOCIATED WITH THE DEVELOPMENT OF INTERNAL NECROTIC DISORDERS OF POTATO

Physiological disorders such as Brown Center and Internal Brown Spot a ffect the quality of potato tubers destined for fresh and processing m arkets. Cultural and environmental factors giving rise to such disorde rs have been studied extensively. Considerably less information is ava ilable on the underpinning physiological, molecular and biochemical me chanisms. However, the cell's calcium status clearly plays an importan t role in resistance responses. Whilst extreme genotypic susceptibilit y to these disorders exist such variation has not been exploited fully to dissect the genetics and biochemistry of the key processes. This i s central to the selection of resistant germplasm or to the manipulati on of existing genotypes for improved tolerance.