soil moisture above 65% of the available soil water (ASW) capacity has been shown to produce high tuber set when compared to lower moisture levels. Uneven growth of the potato plant, and therefore uneven growth of tubers, can result in abnormalities in tuber shape. Fluctuating temperatures, moisture, and nitrogen, especially in the formative stage, can cause malformed tubers. Uneven growth caused by variable climactic conditions is worsened by poor plant stand and variability between plants caused by variable seed-piece types, sizes and spacings. Tuber Quality (M. Scanlon) Nutritional Quality Potatoes are a nonfattening, nutritious and wholesome food that supplies many important nutrients to the diet. Potatoes contain approximately 78% water, 22% dry matter (specific gravity) and less than 1% fat. About 82% of dry matter is carbohydrate, mainly starch, with some dietary fibre and small amounts of various simple sugars. Although potatoes contain only relatively little protein (0.6-1.2% of the fresh weight), their nutritional quality is better than cereals or soybeans. Potatoes contain at least 12 essential vitamins and minerals, are a source of vitamin C, thiamine, iron and folic acid. Fresh-Market Quality influences consumer preference and product saleability. Good quality potatoes are clean, uniform in shape and size, have an unmarked skin and firm flesh, are free of internal defects, and have shallow eyes. Consumers do not like the waste of trimming potatoes with deep eyes and surface defects. Other tuber defects that may adversely influence quality are greening, secondary growth, growth cracks, scab, storage rots, internal black spot,