Publication Date

1997

Description

Seedling root fluorescence has generally been used to discriminate perennial ryegrass (Lolium perenne L.) from Italian ryegrass (L. multiflorum Lam.). The trait, however, has introgressed between the two species and breeders now determine fluorescence levels for new ryegrass cultivars. Our objective was to ascertain genetic change for fluorescence expression during generations of seed multiplication. Four ryegrass populations, differing in fluorescence levels, were increased three generations at each of three Oregon locations. Fluorescence levels were measured for each generation cycle at each location. Variation was present for fluorescence among locations within populations and for seed production generation within locations. One population, for example, initially at 10% fluorescence increased to 36% over three generations of seed multiplication at one location, but decreased to 8 and 2% at the other two locations. This large effect of location and seed generation on fluorescence expression must be examined and carefully considered when describing fluorescence levels of cultivars for seed certification.

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Genetic Shift of Seedling Fluorescence in Ryegrass Over Seed Increase Generations

Seedling root fluorescence has generally been used to discriminate perennial ryegrass (Lolium perenne L.) from Italian ryegrass (L. multiflorum Lam.). The trait, however, has introgressed between the two species and breeders now determine fluorescence levels for new ryegrass cultivars. Our objective was to ascertain genetic change for fluorescence expression during generations of seed multiplication. Four ryegrass populations, differing in fluorescence levels, were increased three generations at each of three Oregon locations. Fluorescence levels were measured for each generation cycle at each location. Variation was present for fluorescence among locations within populations and for seed production generation within locations. One population, for example, initially at 10% fluorescence increased to 36% over three generations of seed multiplication at one location, but decreased to 8 and 2% at the other two locations. This large effect of location and seed generation on fluorescence expression must be examined and carefully considered when describing fluorescence levels of cultivars for seed certification.