Phosphorus Use Efficiency of Wheat Genotypes Grown in Calcareous Soils

Phosphorus (P) deficiency and low P-use efficiency are induced by soil properties, especially in calcareous soils, which are dominant in semi-arid regions of the world such as the Mediterranean region. Alternative approaches to P fertilization involve exploiting plant genetics in order to achieve more efficient use of P by the growing crop. Accordingly, in a greenhouse pot experiment, we evaluated P-efficiency in wheat genotypes grown in typical calcareous soils in southern Turkey. Ten common local genotypes were grown in six soil series for eight weeks using five P application rates (0, 25, 50, 100, and 200 mg P kg-1). Dry matter (DM) yield and P content were significantly increased by increasing P rates, with significant differences between soils. Some genotypes performed better under P stress because of better P utilization efficiency. Shoot DM was the most sensitive indicator of genetic variability under P-deficient conditions. Genotypes classified as efficient-responsive (Adana-99, 1014, Golia, Balatilla) had above average DM yield when P was not added, and responded well to P applications; efficient-non-responsive genotypes (Firat-93, Seri-82, Genc-99, Panda) had below average DM yield, but responded to P applications; inefficient-non-responsive genotypes (Fuat Bey and Ceyhan-99) had below average DM yield; and no genotypes were in the inefficient responsive category. Such P response categorization is needed for better breeding programs for nutrient-use efficiency. The study may aid in selecting P-efficient genotypes in low-P soils, especially where little P is used. The use of P-efficient genotypes should be seen as complement to, rather than a substitute for, chemical P fertilization depending on local conditions.