Orthology guided transcriptome assembly of Italian ryegrass and meadow fescue for single-nucleotide polymorphism discovery

Single-nucleotide polymorphisms (SNPs) represent natural DNA sequence variation. They can be used for various applications including the construction of high-density genetic maps, analysis of genetic variability, genome-wide association studies, and mapbased cloning. Here we report on transcriptome sequencing in the two forage grasses, meadow fescue (Festuca pratensis Huds.) and Italian ryegrass (Lolium multiflorum Lam.), and identification of various classes of SNPs. Using the Orthology Guided Assembly (OGA) strategy, we assembled and annotated a total of 18,952 and 19,036 transcripts for Italian ryegrass and meadow fescue, respectively. In addition, we used transcriptome sequence data of perennial ryegrass (L. perenne L.) from a previous study to identify 16,613 transcripts shared across all three species. Large numbers of intraspecific SNPs were identified in all three species: 248,000 in meadow fescue, 715,000 in Italian ryegrass, and 529,000 in perennial ryegrass. Moreover, we identified almost 25,000 interspecific SNPs located in 5343 genes that can distinguish meadow fescue from Italian ryegrass and 15,000 SNPs located in 3976 genes that discriminate meadow fescue from both Lolium species. All identified SNPs were positioned in silico on the seven linkage groups (LGs) of L. perenne using the GenomeZipper approach. With the identification and positioning of interspecific SNPs, our study provides a valuable resource for the grass research and breeding community and will enable detailed characterization of genomic composition and gene expression analysis in prospective Festuca Lolium hybrids

Genetic gains in nordic spring barley breeding (1930searly 1990s)

Accurate assessments of genetic gains ensuing from plant breeding for the most important agronomic characteristics in Nordic spring barley (Hordeum vulgare L.) are not available. Hence this research was aimed to determine the rate of genetic improvement in the Nordic barley breeding pool. This study included 90, 2-row spring barley cultivars released (1942–1988) and 29, 6-row spring barley cultivars released (1930–1991) adopted by Nordic farmers that were tested in four Nordic locations for three consecutive years. Relative genetic gain owing to plant breeding was 13%in 2-row barley and 34%in 6-row barley for grain yield. The absolute gain for this characteristic was 13 ± 3 kg ha−1year −1 in 2-row barley, and 22 ± 3 kg ha−1year−1 in 6-row barley. Improved yield was achieved in Nordic barley by reducing plant height (0.20 ± 0.04 cm year−1 for 2-row barley and 0.16 ± 0.06 cm year−1 for 6-row cultivars), thereby reducing significantly lodging (0.5 ± 0.1% year−1 and 0.4 ± 0.1 year−1), and increasing significantly the harvest index (0.0008 ± 0.0002 year−1 and 0.0018 ± 0.0002 year−1). Additionally, in 2-row spring barley cultivars resistance to powdery mildew (0.19 ± 0.08% year−1) and thousand-kernel weight (0.07 ± 0.03 g year−1) were also significantly enhanced, whereas hectoliter weight was improved (0.06 ± 0.02 kg year−1) in 6-row barley cultivars in the period investigated.