Genomic prediction ability for yield-related traits in German winter barley elite material.

KEY MESSAGE: Genomic prediction was evaluated in German winter barley breeding lines. In this material, prediction ability is strongly influenced by population structure and main determinant of prediction ability is the close genetic relatedness of the breeding material. To ensure breeding progress under changing environmental conditions the implementation and evaluation of new breeding methods is of crucial importance. Modern breeding approaches like genomic selection may significantly accelerate breeding progress. We assessed the potential of genomic prediction in a training population of 750 genotypes, consisting of multiple six-rowed winter barley (Hordeum vulgare L.) elite material families and old cultivars, which reflect the breeding history of barley in Germany. Crosses of parents selected from the training set were used to create a set of double-haploid families consisting of 750 genotypes. Those were used to confirm prediction ability estimates based on a cross-validation with the training set material using 11 different genomic prediction models. Population structure was inferred with dimensionality reduction methods like discriminant analysis of principle components and the influence of population structure on prediction ability was investigated. In addition to the size of the training set, marker density is of crucial importance for genomic prediction. We used genome-wide linkage disequilibrium and persistence of linkage phase as indicators to estimate that 11,203 evenly spaced markers are required to capture all QTL effects. Although a 9k SNP array does not contain a sufficient number of polymorphic markers for long-term genomic selection, we obtained fairly high prediction accuracies ranging from 0.31 to 0.71 for the traits earing, hectoliter weight, spikes per square meter, thousand kernel weight and yield and show that they result from the close genetic relatedness of the material. Our work contributes to designing long-term genetic prediction programs for barley breeding.

Burkholderia bryophila sp. nov. and Burkholderia megapolitana sp. nov., moss-associated species with antifungal and plant-growth-promoting properties.

A polyphasic taxonomic study including DNA-DNA reassociation experiments and an extensive biochemical characterization was performed on 14 Burkholderia isolates from moss gametophytes of nutrient-poor plant communities on the southern Baltic Sea coast in northern Germany. The strains were classified within two novel species, for which the names Burkholderia bryophila sp. nov. and Burkholderia megapolitana sp. nov. are proposed. The former species also includes isolates from grassland and agricultural soil collected in previous studies. Strains Burkholderia bryophila 1S18(T) (=LMG 23644(T) =CCUG 52993(T)) and Burkholderia megapolitana A3(T) (=LMG 23650(T) =CCUG 53006(T)) are the proposed type strains. They were isolated from Sphagnum rubellum and Aulacomnium palustre, respectively, growing in the 'Ribnitzer Grosses Moor' nature reserve (Mecklenburg-Pommern, Germany). All moss isolates of both novel species showed antifungal activity against phytopathogens as well as plant-growth-promoting properties.