Peanut production in Thailand is concentrated in upland area under rain-fed conditions. Unpredictable time and the extent of water deficit occurs every year and causes a reduction in yield and quality. Under these conditions the use of cultivars tolerant to drought and producing high yield should be advantageous. The objective of this study was to investigate the effect of water stress on yield and agronomic characters of peanut cultivars. A glasshouse experiment was conducted for evaluation of 4 peanut cultivars, Tainan 9, Khon Kaen 60-3, ICGV 98308 and ICGV 98324, under three regimes of water (field capacity, ½ available water and ¼ available water) in earthen pots. A 4×3 factorial experiment in randomized complete block design with 4 replications was conducted. Total dry weight, pod yield, seed yield, 100 seed weight and shelling percentage were determined at the final harvest. At field capacity, all peanut cultivars performed well. Yield and agronomic characters of all cultivars were decreased under water stress; and significant response of genotypes was observed. Khon Kaen 60-3 and ICGV 98308 were more sensitive to water stress, comparing with Tainan 9 and ICGV 98324.
