Genotype and environmental interaction effect on heterosis expression in maize

The three-year studies on effects of irrigation and sowing densities were carried out on chernozem at Zemun Polje in the period 1998-2000. The four-replicate trial was set up according to the split-plot design. Six ZP maize hybrids (ZP 360, ZP 539, ZP 580, ZP 633, ZP 677. and ZP 704) were sown in seven densities (40,816, 50,125, 59,523, 69,686, 79,365, 89,286 and 98,522 plants ha-1) under both, irrigation and rainfed conditions. Obtained results indicate that yields of hybrids under irrigation conditions were lower at sowing densities up to 50.000 plants ha-1 (40,816 and 50,125). The hybrid ZP 539 had similar yields (13.44-13.93 t ha-1) at densities ranging from 60,000 to 100,000 plants ha-1. The highest yields of hybrids ZP 360 and ZO 580 were achieved with the densities of 80,000, 90,000 and 100,000 plants ha-1. The hybrid ZP 633 had the highest yields at the densities of 60,000-90,000 plants ha-1, while the highest yields of the hybrids ZP 677 and ZP 704 were achieved with densities of 60,000-100,000 plants ha-1. The curvilinear regression was determined by the analysis of dependence of achieved yields of maize hybrids on sowing densities. The following maximum yields could be expected under irrigation conditions: ZP 360 - 14.19 t ha-1 with the sowing density of 93,500 plants ha-1; ZP 539 - 14.03 t ha-1 with the sowing density of 78,500 plants ha-1; ZP 580 - 14.41 t ha-1 with the sowing density of 95,700 plants ha-1; ZP 633 - 13.64 t ha-1 with the sowing density of 80,000 plants ha-1: ZP 677 - 13.31 t ha-1 with the sowing density of 92,250 plants ha-1 and ZP 704 - 14.33 t ha-1 with the sowing density of 84,111 plants ha-1.
Trogodišnja proučavanja uticaja navodnjavanja i gustine setve obavljena su u periodu 1998-2000 u Zemun Polju na černozemu. Ogled je postavljen po split-plot metodi, u četiri ponavljanja. U uslovima sa i bez navodnjavanja, u sedam gustina setve (40816, 50125, 59523, 69686, 79365, 89286 i 98522 plants'ha-1) sejano je šest ZP hibrida kukuruza (ZP 360, ZP 539, ZP 580, ZP 633, ZP 677, ZP 704). Rezultati proučavanja pokazuju da su u navodnjavanju svi hibridi statistički veoma značajno niže prinose ostvarili u gustinama setve sa oko 50.000 bilj.ha-1 (40.816 i 50.125 bilj.ha-1). Hibrid ZP 539 u svim ostalim gustinama (60-100.000 bilj.ha-1) imao je približne vrednosti prinosa (13,44 t ha-1- 13,93 t ha-1). Najbolje rezultate prinosa hibridi ZP 360 i ZP 580 ostvarili su u gustinama 80, 90 i 100.000 bilj.ha-1, hibrid ZP 633 u gustinama 60, 70, 80 i 90.000 bilj.ha-1, a hibridi ZP 677 i ZP 704 u gustinama 70, 80, 90 i 100.000 bilj.ha-1. Analizom zavisnosti ostvarenih prinosa hibrida kukuruza od gustine setve utvrđena je krivolinijska regresija. U navodnjavanju mogu se očekivati sledeće vrednosti maksimalnih prinosa: ZP 360 - 14,19 t ha-1 setvom u gustini 93.500 bilj.ha-1, ZP 539 - 14,03 t ha-1 u gustini 78.500 bilj.ha-1, ZP 580 - 14,41 t ha-1 u gustini 95.700 bilj.ha-1, ZP 633 -13,64 t ha-1 u gustini 80.000 bilj.ha-1, ZP 677 - 13,31 t ha-1 u gustini 92.250 bilj.ha-1 i ZP 704 - 14,33 t ha-1 u gustini 84.111 bilj.ha-1.