Relationships between orchardgrass seed and forage production in Indiana and seed production in Oregon
Abstract
Orchardgrass is an important forage species in the eastern United States, but nearly all commercial seed is produced in Oregon. The objectives of this study were (1) to determine relationships among orchardgrass seed yield traits, and (2) to examine the feasibility of selection in Indiana for improved seed yield in Oregon. Twenty-four orchardgrass parents and their polycross progenies were randomly selected from a reference population, and established as spaced plants at Battle Ground and Buck Creek, Indiana, and Salem, Oregon for evaluation of seed yield and associated traits. Progenies were also established as seeded rows at all locations for seed yield evaluation, and as solid-seeded plots at the Indiana locations for forage yield evaluation. In the space-planted study, genotypic variation was found for panicle number, seed yield, and yield per panicle in Indiana and Oregon, and for stem rust resistance in Indiana. Phenotypic correlations indicated that panicle number and yield per panicle were associated with seed yield. Genotype x location interactions between Indiana and Oregon were significant for panicle number, seed yield, and yield per panicle. Phenotypic and genetic correlations for the same trait measured in Indiana and Oregon tended to be low. Heritability values and parent-progeny correlations for seed yield were low at all locations. Genotypic variation for seed yield was detected only in Oregon among seeded progeny rows. Phenotypic and genetic correlations for seed yield between Indiana and Oregon seeded progeny rows were low. Phenotypic correlations for seed yield between progeny spaced plants and seeded rows were low and non-significant. Correlations of progeny forage yield in Indiana with Indiana and Oregon seed yields were low and non-significant. Low phenotypic and genetic correlations for seed yield between Indiana and Oregon, and significant genotype X location interactions indicated that it would be difficult to improve Oregon seed yield through selection in Indiana within this population. The low heritability values indicated that family selection may be necessary to improve seed yield. Selection for improved seed yield should not adversely affect forage yield or level of stem rust resistance in this population.
Degree
Ph.D.
Advisors
Ohm, Purdue University.
Subject Area
Agronomy
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