Genetic diversity of Brassica cultivars in relation to phosphorus uptake and utilization efficiency under P-stress environment

Abstract

Phosphorus (P) plays a central role in plant cell metabolism. Therefore, low P availability is one of the major constraints for plant productivity in natural and agricultural ecosystems. The addition of phospahtic fertilizers is economically not feasible for resource-poor farmers as the efficiency of added P fertilizers is often low. Plants have evolved a myriad of adaptive mechanisms to increase P uptake and P-utilization efficiency (PUE). Plant efficiency for P uptake and PUE may contribute to improve crop-yield potential in resource-poor environments and selection of P-efficient cultivars can enhance productivity on low fertility soils and reduce fertilizer requirements. A controlled-climate chamber was used to investigate the performance of 14 hydroponically grown Brassica cultivars. Cultivars differed significantly in biomass accumulation (shoot and root dry matter), root-shoot ratio, P concentrations and contents in plant parts, relative reduction in biomass accumulation due to P stress or P-stress factor (PSF) and PUE indicating considerable diversity among the tested cultivars. PUE and the proportional increases in shoot dry matter (SDM) production (SDMmax/SDMmin) in response to the P levels assisted in differentiating plants into efficient and inefficient utilizers of the absorbed P. Cultivars were classified into efficient responsive (ER), efficient non-responsive (ENR), non-efficient responsive (NER) and non-efficient non-responsive (NENR). Efficient cultivars showed the lowest shoot P concentrations and PSF, and the highest biomass accumulation and PUE.