engleski

Grain Yield and Quality of Semiflint Maize Hybrids at Two Sowing Dates

Hybrid selection has an important influence on specific end-use of maize (Zea mays L.) grain. Field experiments were conducted to evaluate the grain yield and quality of four recently released (1999-2002) maize hybrids compared to a check hybrid Bc 462 released in 1982. All hybrids were of semiflint type, that belong to the various maturity groups (FAO 200-400). Hybrids were grown over two years at the optimum (around 1 May) and delayed (about two weeks later) sowing dates. Grain yields were significantly higher in the growing season of 2004 averaging 7247 kg ha-1 compared to 6114 kg ha-1 in 2003. Larger grain yields in 2004 were primarily associated with the heavier 1000-kernel weights. Grain protein and oil contents did not vary across two years and averaged 112 and 43.4 g kg-1, respectively. Hybrids signifi cantly differed in grain yield, yield components and grain quality traits. A new, longer-maturity hybrid Zlatko produced the largest grain yields, which were by 22 % higher than those of the lowest yielding Tvrtko 303, a shorter-season hybrid. Sowing date did not affect grain yield and protein content in any of the tested hybrids, but all hybrids tended to have slightly, yet significantly lower oil content with delayed sowing date. A full-season check hybrid Bc 462 had significantly higher grain protein and oil content than all recently released hybrids, which did not diff er among themselves for those quality traits. However, Bc 462 produced signifi cantly smaller protein, oil and starch yield per hectare than Zlatko because of lower grain yields for the former. Positive correlation existed between grain protein and oil content among tested hybrids, whereas these quality traits negatively correlated with grain yield and starch content. Thus, end-users that require high grain quality maize may need to provide incentives to growers to off set the negative correlation of grain yield with protein and oil content.

yield components; grain protein; grain oil; grain starch

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