Summary:

The aim of the study was to evaluate the precipitation needs of mid-late and late potato using the method of cluster analysis. The research material was based on the results of COBORU (Research Centre for Cultivar Testing) experi-ments carried out in 1972–2001 for the pattern of mid-late and late potato grown on soils of rye complexes, at 23 research stations all over Poland. Meteorologi-cal data: monthly precipitation and the mean temperature of air during the vege-tation of potato were gathered from all the meteorological points functioning at COBORU experimental stations or from the nearest IMGW (Institute of Meteorology and Water Management) stations. For the evaluation of precipitation needs of potato the method of generalized cluster analysis was used. As a result of the method used, three clusters were selected. They differed significantly with regard to the values of 7 variables taken into consideration. The highest yield of potato (cluster 1) was obtained at average values of mean air temperature in the period from May to September (15.2oC), lower than the aver-age precipitation total in May (45 mm), moderate precipitation in June (65 mm) and more than average precipitation in July (90 mm), August (75 mm) and in September (60 mm). The largest deficiency in precipitation in relation to the needs of mid-late and late potato occurs in the north-western and mid western parts of the country.