Conservation of Grass Collections at the Western Regional Plant Introduction Station

Germplasm managers at the Western Regional Plant Introduction Station (WRPIS) have focused on improving seed regeneration in forage and turf grass species through studies of diversity maintenance, using isozyme markers in annual ryegrass (Lolium multiflorum Lam.) and through studies of pollen isolation, using strains of dominant pubescent and recessive glabrous smooth bromegrass (Bromus inermis Leyss.). Balanced samples of annual ryegrass (an equal number of seeds per plant) from field plots were best for maintaining allelic frequencies, but genetic diversity (heterozygosity and allelic richness) was maintained nearly as well in bulk samples (seeds proportionally assembled according to seeds per plant) during early regeneration cycles. In 1995, bromegrass marker plots integrated into WRPIS seed-regeneration nurseries at two locations resulted in average contamination of 4.2% at distances between 22 and 27 m. Diversity maintenance in early regeneration cycles and a relatively low level of pollen contamination appear possible in bulk samples and with modest isolation distances.