Phosphorus-use efficiency in wheat genotypes

Phosphorus (P) deficiency is one of the principal yield-limiting factors in Oxisols in various parts of the world. The objective of this study was to evaluate 15 wheat genotypes for P-use efficiency. The genotypes were evaluated in an Oxisol at zero ("low" P), 75 mg P kg(-1) ("medium" P), and 150 mg P kg(-1) ("high" P). Shoot weight and P uptake in shoot were the most sensitive plant parameters to P deficiency. Significant (P<0.01) genotypic differences in P-use efficiency were found. Phosphorus-use efficiency is represented as mgs of dry matter of root and shoot per mg of P accumulated in root and shoot. On the basis of P-use efficiency, genotypes were classified as efficient and responsive (ER), efficient and nonresponsive (ENR), nonefficient and responsive (NER), and nonefficient and nonresponsive (NENR). From a practical point of view, genotypes which produce high shoot dry matter in a low level of P and respond well to added P are the most desirable because they are able to express their high yield potential in a wide range of P environment. Genotypes BR10, CPAC89128, and NLA59 fall into this group. These are often referred to as widely adapted genotypes, in contrast with other genotypes which can be referred to as more specifically adapted genotypes.