Browsing by Subject "Silage Maize"

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Untersuchungen zur Vererbung von Qualitätseigenschaften bei Silomais (Zea mays L.)
(2004) Krützfeldt, Birte A. E.; Geiger, Hartwig H.
In central Europe silage maize (Zea mays L.) is a major source of cattle feed. The quality or the feeding value of a silage maize variety mainly depends on its digestibility and energy content. The establishing of the near-infrared-reflectance-spectroscopy- (NIRS) technique allows the analysis of more than one quality determining trait simultaneously in an easy and short way. In this study one objective was the influence of stover quality on whole plant quality. In hybrid breeding indirect selection on the basis of inbred line performance has a great advantage because the number of testcrosses can be reduced. Therefore it was tested, if the stover quality of the testcrosses could be predicted on the line per se value. Besides the correlation between agronomic and quality traits was analysed. In the years 1999 and 2000 the evaluation of the stover of the lines and testcrosses and the whole plant of the testcrosses was conducted at four climatically diverse sites in Germany. Three data sets with flint-lines and dent-lines, each proved with one tester-line, were evaluated for the correlation between inbred line and testcross performance. The test for combining ability was performed with three smaller data sets also consisting of flint-lines and dent-lines with two tester-lines per data set. The coefficients of heritability were high for the agronomic and quality traits in the data sets of the inbred lines. In the data sets of the testcrosses the variation attributed to the genotypic variance was smaller, genotype × location-interactions were of lower importance. In the data sets, each with two tester-lines it was obvious that for quality traits of stover and whole plant the interaction between line and tester was mostly not significant. The genotypic correlation between inbred line and testcross performance was highly significant for almost all quality traits of the stover, but the correlation coefficients were mostly only moderate. Only the expected success of an indirect selection on line per se- value for cell-wall digestibility of the stover exceeded that of the direct selection on testcross performance in all data sets. However, a selection of extremes on line per se value should be possible for stover digestibility. The genotypic correlations between comparable traits in stover and whole plant were mainly low. The cell-wall digestibility was the only trait which was independent of dry matter content. For evaluation of the further quality traits attention has to be paid to the maturity stage, to prevent a maturity-based bias of the results. In the testcrosses stover digestibility increased and whole plant digestibility was reduced with an increase in whole plant dry matter yield. But the genotypic correlations were only moderate and a simultaneous selection to improve quality and yield seems to be possible.