Genotypic variations in phosphorus use efficiency and yield of some groundnut cultivars grown on an Alfisol at Samaru, Nigeria

A field trial was conducted in 2008 at the Institute for Agricultural Research farm at Samaru, to evaluate the phosphorus uptake, phosphorus use efficiency (PUE) and yield potentials, of five groundnut (Arachis hypogaea L.) genotypes (SAMNUT 10, 11, 21, 22 and 23). Four levels of phosphorus (0, 20, 40 and 60 kg P2O5 ha-1) were applied to each genotype in a randomized complete block design (RCBD ) with three replications. In addition to PUE indices, haulms and pod yields were also recorded. Among the genotypes evaluated, SAMNUT 23 recorded the highest total P uptake of 68.96 mg P kg-1 while SAMNUT 10 recorded the least (44.22 mg P kg-1). SAMNUT 23 also produced the highest (2,298 kg ha-1) dry pod yield. The highest PUE of 71.71 and 64.53% were recorded by SAMNUT 10 and 21 respectively, while SAMNUT 23 recorded the least (31.46%) PUE. The early or medium, maturing genotypes, SAMNUT 21 and 22, were observed to be better than both the extra-early, SAMNUT 23, and late-maturing SAMNUT 10 and 11, in terms of dry haulms yield. Therefore, SAMNUT 10 and 21 had greater adaptation for low soil P conditions than the other genotypes, and hence more suitable to resource-poor farmers.