CORRELATIONS BETWEEN THE BIOLOGICAL VALUE OF THE SEED AND THE YIELD COMPONENTS OF HYBRID MAIZE (ZEA-MAYS L.)

The aim of the experiments was to determine how the different seed fra ctions of experimental and registered maize hybrids transfer differenc es in seed biological value to the flowering time, seed moisture conte nt, thousand kernel weight and, last but not least, to the yield compo nents. The 1995 experiments were expanded to include new seed-dressed and undressed treatments. Based on the yields achieved with dressed fr actions it was found that for all the hybrids the yield of the flat fr actions tended to surpass that of the round fractions. The data of 50 % tasselling and 50 % silking indicated that the differences between t he flowering times of the fractions were never great enough to cause p oorer fertilisation. The yield figures are confirmed by the results of a stressing vigour test, i.e. seed with better biological value retai ns a certain superiority in yield due to its greater vigour. However, favourable environmental conditions at sowing (soil and air temperatur e, water supplies) may reduce the differences between the various frac tions. Special mention should be made of the small round fraction, whi ch generally produced the lowest yields. Due to differences in the exp erimental sites, fractionation may be of importance not only as regard s the genotype, but also as regards the growing site, the production c onditions and the environmental factors. In general, data indicating a definite advantage in favour of flat fractions were obtained in exper iments involving dressed seeds, while undressed seeds are more prone t o infection, thus leading to wider deviation in the results. Generally the coated seeds, - as a treatment - experiments could prove the supe riority of the flat fractions. In case of uncoated uncoated seeds, the seed fungical infections can be change the seed emergence and could r esult different datas.