engleski

Response of corn hybrids to soil stress in acid soil

Soil stresses induced by different types of nutrient imbalances are the reason for low maize grain yields on some arable lands of the Eastern Croatia region. Acid reaction, low P supply and other abiotic stresses are limiting factor for crop yields on some soils situating mainly in the west part of province. No information exists on differential capacity of different maize genotypes to produce economic yields under abiotic stress conditions. Tweenty four corn hybrids were grown in area of Pozega-Slavonian county on stagnosol (acid soil of moderate fertility) during the growing season 1996. By soil testing (0-30 cm depth) they were found properties as follows: pH in H2O 4.80 ; pH in 1nKCl 3.60 ; humus 1.15% ; EUF-test (mg/100 g of soil: extraction 20 and 80oC, respectively) = 1.45 and 0.64 P, 11.6 and 3.2 K, 10.6 and 4.2 Ca, 3.68 and 1.58 Mg, respectively. There were three groups (seven hybrids/group) of corn hybrids with the have same inbred line as a male parent (either Os 1- 48, Os 2-48 or Os 3-48, respectively), while female parents are seven inbred lines as follows: Os86-39, Os84-28, Os89-9, Os87-24, Os84-49, Os84-24 and Os87-61. Remaining three hybrids (OsSK382, Bc408E and OsSK373) were used as standard hybrid for individual group. Field trial was conducted in four replication by randomized block design (experimental plot 7.56m2). Corn was sown at planned plant density 63493 plants/ha (interrow spacing 70 cm, two plants in row on 45 cm distance). Ear-leaf at beginning of silking stage (middle of July) was taken for chemical analysis. Mean sample contained about 25 leaves. Grain yields were calculated on 90% of planned plant density and 14% grain moisture basis. Mean grain yield of the trial was 7.04 t/ha with range of variation among the hybrids from 5.89 to 8.11 t/ha and among three groups from 6.78 to 7.35 t/ha. Seven hybrids yielded more than 7.50 t/ha (mean yield 7.77 t/ha). However, grain yields of six hybrids were less than 6.50 t/ha (mean 6.15 t/ha). Although soil P status were moderate, ear-leaf P concentrations at silking stage were in adequate range (according Bergmann from 0.25 to 0.50% P in dry matter). Differences among the hybrids were from 0.272 to 0.378% P. In general, three groups of hybrids had similar ear-leaf P status (means 0.321% P, 0.323% P and 0.339 % P, for the group with Os1-48, Os2-48 and Os3-48 as male parent, respectively). Also, low connection was found between grain yield and ear-leaf P status. For example, mean ear-leaf P status of high-yielding group (>7.50 t/ha) and low-yielding group (<6.50 t/ha) of hybrids was similar (means 0.336 and 0.330% P, respectively).

corn ; hybrids ; acid soil ; grain yield ; phosphorus ; leaf

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