02930nam a2200301 a 450000100080000000500110000800800410001910000140006024500500007426000380012430000100016250000170017252022160018965000120240565000230241765000130244065000120245365000100246565000260247565000150250165000130251665300180252965300150254765300200256265300100258265300210259265300150261315595742000-02-11       1981    bl uuuu  m   00u1 u    #d1 aSILVA, J.  aFactors affecting production of forage maize.  aAmes: Iowa State Universityc1981  a137p.  aPhD. Thesis.  aA study was conducted to evaluate hybrids, plant populations, and harvest date for forage corn (Zea mays L.) yeld and quality traits. Fiven open-pedigree hybrids of different relative maturities were grown at Nashua, lowa in 1978, 1979, and 1980 at three plant population densities (50,423, 64,829, and 79,235 plants per hectare). A split-plot design was used for traits related to grain yield and a split-split-plot for traits related to forage production. Three differente harvest dates (30,45, and 60 days after mid-silk) were used to determine the relative values for forage traits. Combined analysis of variance detected significant linear effects among plant populations for all traits except mature grain weight, moisture content of mature grain, mature grain corrected for moisture, and harvest index. Harvest index did not show significant effects among plant populations. Increases in dry matter yield and decreases in dry matter content corresponded to increases in plant population levels for dry matter yield. Differences among hybrids were detected in the combined analysis of variance for all traits except dried ear weight and dried grain weight. The latest maturity hybrid (B73 ht x Mo17 ht) was higher and the earliest maturing hybrid (A619 ht x A632 ht) was lower in dry matter yield; na average increase of 20.3% in dry matter yield would be possible with the latest hybrid. Differnces among harvest dates in the combined analyses were significant for green stover weight, dried ear weight, dried grain weight; and harvest index, indicating linear effects. Phenotypic na genotypic correlations between traits for all hybrids, such as between mature grain yield corrected for moisture and dried stover weight (0.605 and 0.597), mature grain corrected for moisture and days to mid-silk (0763 and 0.804), and dried plant weight and days to mid-silk (0.992 and 1.00), were stimated. Relatively later maturing hybrids had acceptable levels of dry matter, crude protein, and digestible dry matter na could possibly be used for forage corn production in short season areas. Further research on qualitative and qualitative forage traits is necessary for developing breeding programs for forage corn.  ahybrids  aÉpoca de Colheita  aForragem  aHibrido  aMilho  aPopulação de Planta  aProdução  aZea Mays  aBrowse plants  aFeed crops  aHarvesting date  aMaize  aPlant population  aProduction