GENOTYPIC AND SPECIES VARIABILITY IN CARBOXYLATE EXUDATION OF WHEAT (Triticum aestivum L.) AND MAIZE (Zea mays L.) IN PHOSPHORUS DEFICIENCY.

Under low phosphorus (P) availability, plants change their root physiology and release more protons and carboxylates to acquire P from residual sources. This ability differs among genotypes. In this situation, P efficient genotypes may be a conceivable way of decreasing the P demand and using applied P efficiently. This study was planned with the objective of screening P efficient wheat and maize genotypes on the basis of carboxylate and proton release under P deficient condition. Five genotypes each of wheat and maize were grown in solution culture with normal and deficient P treatments under CRD (completely randomized design) factorial. At harvest carboxylates, proton and P were analyzed. Results revealed that wheat genotype, SARC-1 and maize genotype, Pioneer-32F10 was better in carboxylate exudation and more release of carboxylates and proton was recorded in these genotypes comparative to other genotypes. Both genotypes also showed better P and phosphorus use efficiency in P deficient treatment compared to normal P treatment. In the case of species, maize roots released more fraction of malate and wheat roots released more fraction of citrate. This genetic difference can be used for the selection of P efficient genotypes for P deficient soils through the breeding process in the future. [ABSTRACT FROM AUTHOR]