The Evaluation and Relationships of some Physiological Traits in Spring Safflower (Carthamus tinctorius L.) under Stress and Non-stress Water Regimes

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 nonstress conditions. Six factors explained about 80% of the total variation, and only 40% 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 34% 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 Factors 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 temperature (at all stages), leaf area index (at stem elongation), and rate of water loss from excised leaf (at grain filling) were the best criteria for screening suitable genotypes under the afore mentioned conditions