| Summary: | Higher grain yield is a key objective in barley (Hordeum vulgare. L) breeding.
Despite extensive research on the genetics of yield and its components, selection for
yield per se is still the most extensively employed because of negative relationships
among components, modest correlations between yield and any particular component,
and the additional resources required for measuring the components. The development
of quantitative trait locus (QTL) detection procedures allows for an alternative
approach to this issue. The objective of this investigation was to determine the
biological basis of observed grain yield QTLs, with particular reference to yield
components and yield-related traits. Yield and yield component traits were assessed in
a population of spring barley doubled haploids from a cross of 'Steptoe' x 'Morex'.
The scope of inference of the experiment was broadened by using reference QTL data
sets from the multiple environment assessment of the same population. Both positive
and negative relationships among yield, component, and related trait QTLs were
observed. The QTL data indicate that indirect selection for yield via yield
components would be ineffective. The yield QTL effects in this germplasm were
largely attributable to lodging and basal internode length. Localization and
interpretation of yield QTLs may be useful for studying orthologous gene expression
in other germplasm and in developing multiple character selection strategies. === Graduation date: 1994
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