Eur. Potato J., Vol. 4 (1961) No. 1 (March)
[Prace Zakladu Ziemniaka, 1: 87-117. (1960) Warsaw]
Vernalization of potatoes
I. K. KUBICKI
The Potato Division of the Institute of Soil Science and Cultivation of Plants carried out investigations on the problem of vernalization of potatoes over the period 1951 to 1956. These investigations included the following problems:
- the influence of vernalization on the development of potatoes during their growth and on yields and quality:
- selection of the period of planting with vernalized tubers:
- determining the period of vernalization for early potato varieties, as well as medium and late varieties;
- elaboration of simple methods of vernalization possibly rendering extensive application in practical agriculture.
Three groups of varieties were used: early (Pierwiosnek), medium (Mittelfrühe), and late
varieties (Ackersegen, Poswieckie Sel, and Capella). Vernalization of these varieties took place under average farm conditions. The tubers were arranged in slat cases 55 x 45 cm to a height of three layers. The cases were stored in such buildings as barns, cattle sheds, pigsties, distilleries. The temperature in these buildings was maintained within a range of 4 to 20 C; daylight was sufficient. The experimental centers were distributed throughout the country.
The results obtaincd can be summarized as follows:
- Vernalization of potatoes considerably increases the yields of both early and late varieties. The following average increases of the yield were obtained: early varieties 21%; medium-late varieties 16%; late varieties 19%. In some cases yield increases of 41% were observed.
Vernalized early varieties give 40% of their final yields in the beginning of July, non-vernalized only 30%. Corresponding figures for the end of July are 75% and 50%.
- Vernalization accelerates plant development, which is evident in the form of earlier emergence, tuber formation and blooming. Under better climatic conditions, for this reason, the period of plant development for vernalized potatoes is longer than for non-vernalized potatoes.
- The selection of periods for planting vernalized tubers depends on weather conditions.
Under normal conditions an early period is the optimum one, i.e. end of April or beginning of May. If the spring is cool and wet a later period is better for vernalized potatoes.
- Not all varieties require an equally long period of vernalization. Early varieties should be vernalized 20 to 30 days, medium-late varieties need 30-45 days, late varieties 60 days.
- Potatoes can be vernalized not only in slat cases but also on the floor of storages, or in shallow ditches 15 cm deep located in quiet spots.