engleski

Genotype influences on zinc status in corn

Yields of arable crops are under environmental and heredity influences and their increases are possible by improvement of soil properties and growing of more adaptable genotypes. Eastern Croatia is a granary of country and its soils are more or less suitable for corn growing. Symptoms of Zn deficiency have been found at early stage of corn, especially on seed-corn crops growing on neutral and calcareous soils. We tested ten corn hybrids and ten inbred lines (parents of corn hybrids using in corn seed production) on two soil types (planosol and eutric cambisol). The field experiments were conducted in spring 1993 by split-plot method in four replicates (planosol: pH in 1n KCl = 4.27; humus = 1.82%; AL-method = 10.3 mg P2O5 and 20.1 mg K2O/100 g of soil; eutric cambisol: pH in 1n KCl = 6.50; humus = 4.09%; AL-method = 27.9 mg P2O5 and 22.2 mg K2O/100 g of soil). Corn was sown manually in term of 27 April 1993. It was sown 3 seed with 50 cm spacing in the row. At early growth of corn (3-4 leaves stage) was reduced number of plants by plucking (two plants in 50 cm spacing: theoretical plant density = 57144 plants/ha). Corn grain yields were calculated on 14% moisture basis and 90% realization of theoretical plant density (for the corn hybrids) and theoretical plant density of mother parent of seed-corn (42 860 plants/ha; 6:2 of mother and father rows distribution). Ear-leaf was taken for chemical analysis at beginning of the silking stage. Mean sample contained about 25 leaves. Plant samples were digested by dry-ashing procedure and Zn status were determined by atomic absorption and calculated on dry matter basis. Mean grain yield of corn hybrids growing on planosol (6.47 t/ha) was 38% lower than on cambisol (10.33 t/ha). Differences of yields among the hybrids (means of both trials) were from 6.22 to 9.81 t/ha: three hybrids (OsSK644, OsSK552 and Bc6661) yielded over 9 t/ha (mean 9.66 t/ha). The highest yield was found by OsSK644 on planosol (8.18 t/ha) and by Bc6661 on cambisol (12.39 t/ha), while OsSK262 had the lowest yield on both trials (5.45 and 6.99 t/ha, for planosol and cambisol, respectively. Mean grain yield of inbred lines growing on planosol (2.12 t/ha) was 53% lower than on cambisol (4.48 t/ha). Differences of yields among individual inbred lines (means of both trials) were from 2.19 to 4.11 t/ha: four inbred lines (Os86-39, W64A, Os1-48 and Os87-24) yielded above 3,50 t/ha (mean 3.88 t/ha), while by three (B73, Mo17 and Os30-8) were found yields until 3.0 t/ha (mean 2.61 t/ha). Five inbred lines could be designated as less tolerant to acid soil stress (B73, Os30-8, Os36-16, Os89-9 and B73: mean 1.53 t/ha) in comparison with remaining tested (Os86-39, W64A, Os77-9, Os1-48 and Os87-24: mean 2.72 t/ha). Ear-leaf Zn contents were in adequate range (over 20 ppm Zn) and there were found differences between soils (40.7 and 29.2 ppm Zn, for planosol and cambisol, respectively) between genotypes (31.3 and 38.5 ppm Zn, for hybrids and inbred lines) as well as and among hybrids (from 26.3 to 38.2 ppm Zn) and among inbred lines (from 29.7 to 48.6 ppm Zn). In general, low connection was found between grain yields and ear-leaf Zn status.

corn; zinc; genotype; yield

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