engleski

Maize hybrid performance as affected by production systems in Croatia.

The use of intensive production systems (IPS) may substantially increase maize (Zea mays L.) yields in Croatia because the national average of 5.37 t ha-1 is low compared with the environmental and hybrid potentials. Field experiments were conducted during 1996 through 1999 to evaluate the agronomic responses of 12 widely grown maize hybrids in both an IPS and an extensive production system (EPS). Hybrids belonged to three maturity groups (FAO 300-FAO 500), each consisting of four hybrids. The IPS involved ploughing at 30 to 32 cm ; fertilization at 213, 130, and 130 kg ha-1 N, P2O5, and K2O ; 60-65 000 plants ha-1 ; and more intensive use of herbicides. The EPS consisted of ploughing at 20 to 22 cm ; fertilization at 105, 104, and 104 kg ha-1 N, P2O5, and K2O ; 37-38 000 plants ha-1 ; and the use of fewer herbicides. Grain yields significantly increased in the IPS and averaged 11 419 kg ha-1 compared with 8 214 kg ha-1 for the EPS. This difference was primarily due to a 47.1 % increase in kernel number per square rneter produced by 50.5 % more ears per hectare, while grain weight per ear and plant, kernel number per ear and plant, and 1000-kernel weight for the IPS decreased by an average of 6.8, 12.8, 2.9, 9.3, and 3.9 %, respectively Longer-maturity groups tended to produce higher grain yields by an average of 7.7 % through heavier 1000-kernel weight (FAO 400 vs. FAO 300) or more kernels per plant (FAO 500 vs. FAO 400). A significant production system x hybrid interaction was found because some hybrids were highly responsive to the IPS while others were not. Thus, hybrid selection appears to be an important decision for Croatian farmers when changing from an EPS to an IPS for maize.

maize; hybrid; production system; grain yield; yield components; EPS extensive production system; IPS intensive production system

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