Effect of seed treatment and time of harvesting on the yield and quality of potatoes for processing

Abstract

The effect of seed source, physiological age and desiccation date on sprout growth, crop development, yield and fry colour following storage was investigated over four seasons for the variety Maris Piper and in a parallel study for the variety Rooster. Seed tubers were obtained from two areas of production, Carlow and Donegal and received physiological ageing for either 0 or 200 day degrees >4oC. Sprout growth, crop development, yield and fry colour following storage was also compared over two seasons in the varieties Maris Piper, Rooster, Fianna and Navan which had received physiological ageing for 200 day degrees >4oC and grown at two sites. Seed source produced an inconsistent effect on dormancy break, sprout growth, emergence, tuber yield and reducing sugar concentration, but had no effect on tuber sucrose concentration or chip fry colour following storage. Physiological ageing advanced sprout growth, crop emergence, crop establishment, usually improved tuber yield and dry matter content but had no effect on chip fry colour following storage. Delaying the desiccation date significantly increased yield in the grade >45 mm in most experiments. Tuber sucrose concentration declined with delay in desiccation date whereas fry colour tended to deteriorate with delay in desiccation date. When the varieties Maris Piper, Rooster, Navan and Fianna were planted at Kildalton, Navan gave the highest yield of tubers >45 mm, while Rooster gave the lightest fry colour following storage.