Genotypic differences in zinc efficiency of Chinese maize evaluated in a pot experiment.

ABSTRACT

BACKGROUND: Zinc (Zn) deficiency, a major problem limiting crop production worldwide, is common on calcareous soils of China. Using such a Zn-deficient soil supplied adequately with plant mineral nutrients, with or without Zn, 30 Chinese maize genotypes were grown for 30 days in a greenhouse pot experiment and assessed for Zn efficiency (ZE), measured as relative biomass under Zn-limiting compared with non-limiting conditions. RESULTS: Substantial variation in tolerance to low Zn nutritional status was observed within the maize genotypes. Tolerant genotypes did not show Zn deficiency symptoms at the studied early seedling growth, and there was a well-defined relationship between shoot dry matter and the ZE trait. ZE values ranged on average from 45 to 100% for shoot dry weight. Under low available soil Zn conditions, shoot and root dry weights, shoot Zn concentration and content, leaf superoxide dismutase (SOD) activity, leaf area and plant height were all correlated with ZE. Shoot Zn and phosphorus (P) concentrations were negatively correlated. CONCLUSION: Three genotypes (L55 × 178, L114 × 178 and Zhongnong 99) were identified as highly Zn-efficient and three (L53 × 178, L105 × 178 and L99 × 178) as very low in ZE. This selection allows further work to evaluate ZE based on grain yield and grain Zn concentration, including field experiments likely to benefit farmers producing maize on Chinese soils low in available Zn.