In order to develop simple sequence repeat (SSR) markers in Italian ryegrass, we constructed a genomic library enriched for (CA)n-containing SSR repeats. A total of 1,544 clones were sequenced, of which 1,044 (67.6%) contained SSR motifs, and 395 unique clones were chosen for primer design. Three hundred and fifty-seven of these clones amplified products of the expected size in both parents of a two-way pseudo-testcross F(1) mapping population, and 260 primer pairs detected genetic polymorphism in the F(1) population. Genetic loci detected by a total of 218 primer pairs were assigned to locations on seven linkage groups, representing the seven chromosomes of the haploid Italian ryegrass karyotype. The SSR markers covered 887.8 cM of the female map and 795.8 cM of the male map. The average distance between two flanking SSR markers was 3.2 cM. The SSR markers developed in this study will be useful in cultivar discrimination, linkage analysis, and marker-assisted selection of Italian ryegrass and closely related species.

The genus Zoysia consists of 16 species that are naturally distributed on sea coasts and grasslands around the Pacific. Of these, Zoysia japonica, Zoysia matrella, and Zoysia tenuifolia are grown extensively as turfgrasses, and Z. japonica is also used as forage grass in Japan and other countries in East Asia. To develop simple sequence repeat (SSR) markers for zoysiagrass (Zoysia spp.), we used four SSR-enriched genomic libraries to isolate 1,163 unique SSR clones. All four libraries contained a high percentage of perfect clones, ranging from 67.1 to 96.0%, and compound clones occurred with higher frequencies in libraries A (28.6%) and D (11.6%). From these clones, we developed 1,044 SSR markers when we tested all 1,163 SSR primer pairs. Using all 1,044 SSR markers, we tested one screening panel consisting of eight Zoysia clones for testing PCR amplifications, from which five unrelated clones, among the eight, were used for polymorphism assessment, and found that the polymorphic information content ranged from 0 (monomorphic loci) to 0.88. Of the 1,044 SSR markers, 170 were segregated in our mapping population and we mapped 161 on existing amplified fragment length polymorphism-based linkage groups, using this mapping population. These SSR markers will provide an ideal marker system to assist with gene targeting, quantitative trait locus mapping, variety or species identification, and marker-assisted selection in Zoysia species.

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To construct an amplified‐fragment length polymorphism (AFLP)‐based molecular linkage map of zoysiagrass, the selfed progenies of a clone consisting of 78 individuals were analysed using 471 AFLP markers derived from 126 PstI/MseI primer combinations. Of these markers, 364 were grouped into 26 linkage groups. The maps covered a total length of 932.5 cM, with an average spacing of 2.6 cM between markers. This information proves useful for gene targeting, quantitative trait loci mapping, and marker‐assisted selection in zoysiagrass.

To develop simple sequence repeat (SSR) markers for the hexaploid forage grass timothy ( Phleum pratense L.), we used four SSR-enriched genomic libraries to isolate 1,331 SSR-containing clones. All four libraries contained a high percentage of perfect clones, ranging from 78.1% to 91.6%. From these clones, we developed 355 SSR markers when tested from 502 SSR primer pairs. Using all 355 SSR markers we tested one screening panel consisting of eight timothy clones to detect the level of polymorphism and identify a set of loci suitable for framework mapping. The SSR markers detected 90.4% polymorphism between the parents of a pseudo-testcross F(1) population. These SSR markers will provide an ideal marker system to assist with gene targeting, QTL (quantitative trait locus) mapping, and marker-assisted selection in timothy.