Drought stress (DS) is considered to be one of main constraints of potato ( Solanum tuberosum) production. A pot trial with a total of 42 potato varieties was conducted in a rain-proofed shed in Hebei, China, to evaluate their drought tolerance (DT) under two water regimes (well irrigated and DS). Under DS conditions, some varieties, such as Hutou, Gaoyuan 7, CE 66 and HS 66, showed good DT. Gaoyuan 7 and Hutou maintained higher tuber yield even under the DS, and so they could be applied for the DT breeding. Plant height was sensitive to drought, but the drought had less effect on plant height of the varieties with strong DT. Drought conditions induced an increase in the tuber number of varieties with strong DT, and a decrease in the number of varieties with weak DT. The specific gravity of tubers was insignificantly affected by the drought. The ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) changed insignificantly under DS, but the effective quantum yield (qY) of leaves decreased sharply.
