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Abstract
Six maize (ZeamaysL.) hybrids (OsSK377, OsSK382, OsSK407, OsSK552, OsSK644 and Bc66-6J) were grown under soil stress conditions characterizing K-deficiency (strong K-fixing soil), excesses of Ca and Mg and moderate supplies ofplant available Fe andMn. Soil is characterized as drained gleysol developed on calcareous loess substrate and its chemical properties was as follows: pH in KCl 7.3; organic matter content 2.4%; carbonate content 14.9%; exchangeable Ca (NH4-Acetate extraction) 603 mgCa/100 and lightly exchangeable Mg (CaCl2-extraction) 38 mg Mg/100 g. The ear- leaf biometals status at silking stage of maize (July 1993) were under significant genetic (hybrid as a factor) influences. The ranges of the ear-leaf composition (mg/kg of dry matter) were as follows: from 8300 to 10600 Ca, from 2570 to 3680 K (acute K deficiency), from 9200 to 11500 Mg (oversupply of Mg), from 15.2 to 18.8 Mn (Mn deficiency), from 20.5 to 25.4 Zn andfrom 131 to 164 Fe (low Fe supply). Grain yields were in range from 1460 to 2470 kg/ha. The Os377 (2470 kg/ha) and the Os382 (2140 kg/ha) were more tolerant to soil stress in comparison with remaining four hybrids (mean yield 1600 kg/ha). Their ear-leaf K status (means 3490 and 2920 mgK/kg, for two more tolerant and four less tolerant hybrids, respectively) could be in connection with different degree of tolerance to soil stress.