J. Ashkani - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.
H. Pakniyat - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.
Y. Emam - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.
M. T. Assad - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.
M. J. Bahrani - Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz, Islamic Republic of Iran.

Eight genotypes of spring safflower (Carthamus tinctorius L.) were evaluated for several physiological traits under stress and non-stress water regimes. Data were analyzed using principal factor analysis. The factor analysis technique extracted six factors under non-stress conditions. Six factors explained about ۸۰% of the total variation, and only ۴۰% of the variance was accounted for by the first two factors. Factors I and II were identified as water consumption, and water balance capacity, respectively. Similarly, seven factors were extracted under stress conditions, and ۳۴% of the total variation was accounted for by the first two factors. Factors I and II were described as water conservation, and water holding capacity, respectively. Important physiological criteria were recognized by Fac-tors I and II in two experiments. Ultimately, initial water content (at stem elongation and grain filling stages), canopy temperature (at stem elongation and flowering stages), and leaf water potential (at flowering stage) under non-stress conditions, and canopy tempera-ture (at all stages), leaf area index (at stem elongation), and rate of water loss from ex-cised leaf (at grain filling) were the best criteria for screening suitable genotypes under the afore mentioned conditions.

Drought resistance, Physiological traits, Principal factor analysis (PFA), Safflower