THE ROLE OF DENSITY IN VARIETAL SPECIFIC MAIZE GROWING TECHNOLOGY

Density of maize hybrids on meadow soil has been studied over 1991-199 3. The fertilizer usage was uniform each year: N150, P100, K150 kg/ha. The stock number changed between 20-100 thousands pro hectare. The tr ial was set by the method of Gyorffy B. The weather is the three exami ned years was considerably different. 1991 was favourable, 1992, 1993 were both droughty. In the growing season of maize precipitation was l ess by 26,4 mm in 1991, 184 mm in 1992, 211.7 mm in 1993 as compared t o the average of many years. It can be stated that the possible densit y of hybrids is different. Plant number has a considerable effect on t he yield. Modem hybrids show a flexible behaviour to increasing densit y and their interval of stock number optimum is wide. With the increas e of stock number the individual production decreases but the yield pr o unit area, improves. Of course stock number/ha can be increased unti l a limited degree because above the optimal stock number the number o f unproductive stock increases, the yield decreases and sensitiveness to fusariumal stock mouldering grows. In the case of modern hybrids th e connection between the growing season and stock number is not signif icant. Increasing of possible density is a genetically controlled char acteristics of hybrids. It is also influenced by the nature of the sit e, the effect of the year and watersupply. In the case of hybrids not only the optimal stock number but also the interval of optimal stock n umber should be determined and the lower value should be used, to devi ate from this value upward is not expedient. Hybrids adaptable to incr easing density are PAU 8301, LG 2379. Hybrids which can have high dens ity are Helga SC, Occitan SC, Stira SC. Sensitive hybrids to increasin g density are Furio SC, Chiara SC, Etalon SC.