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 evalua ted 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 sens itive plant parameters to P deficiency. Significant (P<0.01) genotypic diff erences in P-use efficiency were found. Phosphorus-use efficiency is repres ented as mgs of dry matter of root and shoot per mg of P accumulated in roo t and shoot. On the basis of P-use efficiency, genotypes were classified as efficient and responsive (ER), efficient and nonresponsive (ENR), noneffic ient 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 becaus e 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. The se are often referred to as widely adapted genotypes, in contrast with othe r genotypes which can be referred to as more specifically adapted genotypes .