Abstract: For earlier potato yield formation we used pre-sprouting and thermal treatment which both add to the physiological age of potato. At the same time, pre-sprouting is a very time- and energy-consuming procedure. We investigated if thermal treatment could replace pre-sprouting and how it affects the growth and development of potato haulms and tubers. For that purpose an experiment was conducted in 2000-2002 to examine the opportunities for growing potatoes by using different methods of pre-planting treatment of seed tubers.
Early, middle and late maturing potato varieties (two Estonian varieties and one Latvian) were used, each being subdivided into three variant categories: untreated, thermal shock and pre-sprouting.
The experiment indicated that one or the other of thermal shock or pre-sprouting shortened the time to emergence by up to 10 days. With pre-sprouting, the formation of tubers started as soon as 45 days after planting and with thermal shock 50 days after planting, i.e., 5-10 days earlier than in the untreated variant.
Thermal shock of seed tubers had the greatest effect on the number of tubers per plant, while pre-sprouting increased the average weight of tubers.
Both pre-sprouting and thermal shock had a strong effect on the weight of the haulms in varieties with a longer growth period.