engleski

Genetic and Environmental Influences on Zinc Status in Maize Plants

Zinc deficiency symptoms in maize plants have been appeared on some neutral to alkaline soils of Vukovar, Beli Manastir and Osijek areas (the Eastern Croatia). The mean values of soil test (0-30cm of depth) were as follows: 6.17 and 7.09 (pH in KCl), 5.8 and 2.4 mg of exchangeable Zn/kg for places (the same plot) of normal and chlorotic plants growth, respectively. The analogous comparison of plant properties (aerial part at 6-8 leaves stage) were as follows: 69 cm and 33 cm plant height, 22.0 and 4.4 mg of dry matter/plant, 27 and 20 mg Zn/kg (Kovacevic et al. 1988). These disorders have been especially expressed in seed-maize crops. Concerning this, parents of hybrid maize (inbred lines) are usually different degree of tolerance to soil stress induced by low Zn supply (appearance signs of Zn deficiency in one parent and they absence in the second parent at same plot of seed-maize crop). For this reason, we conducted field experiments of different fertilization treatments as well testing of different genotypes to their zinc status under different soil conditions. In the period from 1991 to 1993, in total 16 field trials were conducted in seed-maize crops. The results of these investigations were mainly shown by Kovacevic et al. (1993). By presowing soil incorporation of 60 kg ZnSO4.7H2O/ha (13 kg Zn/ha), yields of natural seed were increased in seven trials from 10% to 32% compared to control (ordinary fertilization. By increased P and K fertilization (170 kg P2O5 + 170 kg K2O/ha and ordinary fertilization) they were increased in six trials from 8% to 35%. Ten maize inbred line were grown on calcareous gleysol (pH in H2O: 8.30) in four replicates (exp. plot 10.15 m2). They were treated by 0.75% ZnSO4.7H20 solution (twofold in ten days interval at June 1995). Concerning individual inbred lines response to zinc use (Josipovic et al. 1996), they were found differences of grain yields as follows: increasing for 34% (Os84-24), 20% (Os84-49) and 13% (Os64-9) ; decreasing for 22% (Os 1-48) and 18% (Os 2-48 ; yields in range of control (Os86-39, Os87-24, Os 3-48 , Os 84-28 and A672). Four maize inbred lines and their 12 hybrids were grown in four replications (exp. plot 7.0m2) on two soil types (drained gleysol = soil A, lessive soil = soil B) differing of properties (pH in KCl = 6.82 and 4.09 for soil A and soil B, resp.). Plant Zn status in dry matter were estimated by the ear-leaf testing at beginning of the silking stage (middle of July 1992). It was in mean 14.9 mg Zn/kg (Zn deficiency!) and 30.9 mg Zn/kg, for growing on soil A and soil B, resp. Low Zn status are in connection with lower grain yield (mean 4.80 t/ha compared to 7.52 t/ha). Plant Zn on level of genotype was in range from 21.2 to 27.0 mg Zn/kg (means of two trials: Table 1). The higher level of plant Zn in Os1-48 inbred line is in close connection with the higher plant Zn status of their hybrids (Table 1). In general, in the others three inbred lines and their hybrids are something lower the ear-leaf zinc concentrations (Kovacevic et al. 1996). Table 1. The ear-leaf Zn status (means of two experiments: soil A and soil B) of maize (Kovacevic et al. 1996) Father Mother Os1-48 Os84-24 Os86-39 Os87-24 Mean* The ear-leaf Zn (mg Zn/kg of dry matter) at beginning of the silking stage (middle of July 1992) Os 1-48Os84-24Os86-39Os87-24 27.023.824.423.4 23.822.122.321.4 23.721.221.323.5 23.222.621.421.6 24.4 (23.6)22.4 (22.5)22.4 (22.7)22.5 (22.8) Mean* 24.7 (23.6) 22.4 (22.5) 22.4 (22.8) 22.2 (22.4) * in the brackets: means of hybrids (in total 3) only

genetic influences; environmental influences; zinc status in maize plants; genotypes

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