Abstract

The current scientific evidence shows that phosphorus (P) appears to mitigate the adverse effects derived from water deficit stress. However, the efficiency of wheat in the use of both components have been not addressed. The objective of this study was to investigate the combined effect of P and water limiting conditions over phosphorus utilization efficiency (PUTE) and water use efficiency (WUE) to categorize different wheat genotypes. Ten wheat genotypes, including old, current and advanced lines were screened for their ability to utilize phosphorus (P) and water. Plants were grown under controlled conditions on an Andisol with soil P -concentration of 4 mg P kg(-1) (Inadequate P-4 P-), which was enriched to 30 mg P kg(-1) (Adequate P-30 P-). Irrigation was applied at two levels: adequate irrigation (W1) and 30% of W1 (Inadequate irrigation-W2-). Wheat was grown until end of its phenological cycle. The inadequate P and water produced a long delay on plant development, especially on early vegetative stages. As expected, the genotypes showed differences in their growth, development, P accumulation and yield in response to inadequate P and water conditions. The lowest performance in terms of plant growth, development and yield was observed when both the P and water restrictions were applied. Genotypic differences were observed in terms of utilization of P and water. On this basis, wheat genotypes were grouped into three and four classes for PUTE WUE, respectively. The most efficient genotype for all the conditions was "Fritz", which obtained the highest score in the consolidated ranking for PUTE and WUE. On the contrary, "Kiron" was the most inefficient genotype. A strong correlation (similar to 85%) was observed between PUTE and WUE, which could enable the future selection of co-adapted wheat genotypes efficient in the utilization of P and water.