Phosphorus and micronutrient nutrition of chickpea genotypes in a multi-nutrient-deficient typic ustochrept

The chickpea breeding program in India has not yet considered the genotypic variation in phosphorus (P) efficiency, despite the fact that the largest proportion of chickpea-growing soils are P deficient. Since general P application to chickpea is at sub-optimum levels, efficient P-utilizing genotypes will perform better than others under P-deficient conditions. High levels of P application may induce zinc (Zn) deficiency in plants grown on Zn-deficient soils. Twenty chickpea genotypes were evaluated for their P efficiency at varied levels of added P, and the effect of P levels on Zn, iron (Fe), copper (Cu), and manganese (Mn) nutrition was studied in pot-culture experiments. Three criteria were used for evaluating P efficiency; shoot dry-matter yield without P, P-uptake efficiency (PUPE), and P-utilization efficiency (PUSE). Under P-deficiency conditions (control), the genotypes BG-256, HK-94-134, Phule-G-5, and Vikash produced the highest shoot biomass. However, genotypes that were found to be superior in the absence of P did not perform in a similar way under optimum P supply. Root dry weight showed a highly significant correlation with P uptake at all P levels. In the case of PUPE, genotypes KPG-59 and Pusa-209 were found to be superior to others. With increasing P levels, PUSE declined in all the genotypes. Increasing P up to 13.5 mg kg(-1) soil increased Zn concentration, while further increase led to decreased concentration. Genotypes KPG-59, BG-256, RSG-888, and JG-315 showed Zn concentrations below the critical limit of 20 mu g Zn g(-1) dry weight (DW) at the high level of P application (27.0 mg kg(-1)). Iron concentration decreased with increasing P levels. Up to 13.5 mg kg(-1) P application, Cu concentration increased and thereafter decreased. Manganese concentration gradually increased with the increasing P levels studied. Based on three criteria, BG-256 can be recommended for use in P-deficient conditions and can be good germplasm source material for chickpea-breeding programs for evolving P-efficient genotypes. Results also suggest that when selecting P-efficient genotypes of chickpea, it is essential to apply deficient micronutrients.