A method for drought tolerance screening in sunflower

One difficulty in obtaining drought‐tolerant varieties is the unequivocal evaluation of plant response to soil‐water deficits. A method is proposed that allows reproducible soil‐water deficit treatments to be applied to different sunflower genotypes. Maize (Zea mays L.) plants were sown in the same pots as but earlier than some sunflower plants in order to rapidly deplete the soil water. This method was compared to a standard method in which plants under evaluation are used to dry out the soil. The method was reproducible in the evaluation of drought tolerance of four sunflower inbred lines. Advantages of the proposed method are that: (i) it allows the desired soil water content to be reached quickly; (ii) the resulting soil water content in the pot is uniform and (iii) the rate of decrease in soil water content is independent of the genotype being evaluated. Data indicate that maize plants had no effect on the growth of sunflower genotypes.