Spot blotch, caused by Bipolaris sorokiniana, is a damaging disease of barley in Canada, especially in the prairie region (Manitoba, Saskatchewan, and Alberta) where most of Canadian crops are produced. Considerable interaction between isolates of the pathogen and barley genotypes necessitates the evaluation of the virulence diversity in the B. sorokiniana population in order to deploy effective resistance against the pathogen. The virulence diversity of 127 B. sorokiniana isolates from Canada and other countries was evaluated on 12 barley genotypes. Different virulence patterns were detected across B. sorokiniana isolates and eight virulence groups were identified using qualitative analysis of the virulence data. Results indicate broader virulence diversity in the pathogen population in the eastern prairie region of Canada, especially in Manitoba, compared with that previously reported. One group of isolates collected from Manitoba displayed a virulence pattern which had not been reported previously. This group was moderately virulent on most differential lines, including American six-rowed barley genotypes considered to possess durable resistance against B. sorokiniana. Although the classical method of pathotype identification can be exploited to analyze interactions in the barley-B. sorokiniana pathosystem, the continuous range of infection phenotypes found suggests that a quantitative analysis of the complex interactions occurring may be warranted.

Spot blotch, caused by Bipolaris sorokiniana, is a damaging foliar disease of barley (Hordeum vulgare) and other cereal grains in Canada. In order to deploy resistance as an effective management tool, information on the virulence diversity present in the local population of the pathogen is necessary. Speculation regarding the presence of differential virulence versus continuous aggressiveness in B. sorokiniana isolates was begun when isolates with differential virulence on the barley cv. Bowman and its derivatives were reported in North Dakota. To further evaluate the H. vulgare–B. sorokiniana interaction model, the infection responses induced by 127 isolates of the pathogen collected from Canada and other parts of the world were analyzed on 12 differential barley lines using quantitative approaches. Analysis of the data based on infection response elicited on the barley differentials resulted in an enhanced understanding of the host–pathogen interactions and in the relationships among isolates, compared with the classical method of pathotype identification. The population of B. sorokiniana was determined to consist of three distinct pathogenic groups (having low virulence, differential virulence, and virulence with varying levels of aggressiveness). The results of the various quantitative approaches indicated that complex interactions exist among barley genotypes and B. sorokiniana isolates of the third pathogenic group which cannot be analyzed easily using the classical method of pathotype identification. It also was inferred that the gene-for-gene model is not the principal system operating in the H. vulgare–B. sorokiniana pathosystem, although this plays a role in some interactions.

In multi-environment trials (METs), the study of genotype × environment (GE) interaction is important for identifying high-yielding and stable or specifically adapted genotypes. The main objective of this study was to evaluate the GE interaction via GGE biplot analysis using some promising barley (Hordeum vulgare L.) lines evaluated in an MET to identify genotypes possessing high yield and yield stability in the cold regions of Iran. Eighteen promising barley lines, along with two check cultivars, were evaluated during two consecutive cropping seasons (2016–17 and 2017–18) at six research stations located in different regions of the cold zone. The results demonstrated that G1, G2, G4, and G8 were among those with high-yield and stable performance across environments. Moreover, GGE biplot analysis identified these genotypes along with G19 and G20 as the most ideal genotypes. Of these, G8 and G20 showed the highest yield performance. Genotype G15 (Germunk3) was specifically adapted for some regions such as Hamadan province. On the other hand, genotype G8 (Makouee/Jolgeh) had general adaptability across different environments and can be recommended as a new barley genotype for cultivation in most cold regions of Iran.

The interaction between genotypes and environments plays an important role in selecting superior genotypes for target locations. The main objectives of the present study were to analyze the effect of the genotype-by-environment interaction (GEI) and identify superior, newly developed, and promising barley genotypes for cold regions in Iran. For these purposes, a set of genotypes obtained from breeding programs for cold climates in Iran, along with two reference genotypes, were investigated at eight research stations (Tabriz, Ardabil, Arak, Miandoab, Mashhad, Jolge Rokh, Karaj, and Hamadan) during two consecutive growing seasons (2019–2020 and 2020–2021). The results of the freezing test (LT₅₀) showed that most of the tested genotypes had significant cold tolerance at the seedling stage. Based on the additive main effect and multiplicative interaction (AMMI) analysis, environment (E) and GEI effects explained 49.44% and 16.55% of the total variation in grain yield, respectively. Using AMMI1 and AMMI2 models, G2 and G20 were found to be superior genotypes in terms of grain yield and stability. Moreover, AMMI-based stability parameters considered the G20 genotype to be the ideal genotype. A two-plot analysis of the genotype-by-environment interaction (GGE) biplot showed that the 16 experimental environments were grouped into 2 mega-environments. Of the test environments, ARK1 and KAJ2 had the highest discriminating power and representativeness ability, and these were identified as ideal environments for testing advanced genotypes for yield and stability performance during early barley breeding practices in cold areas in Iran. In conclusion, both AMMI and GGE biplot models identified several superior genotypes, among which G20, with a high average yield relative to the overall average yield and the lowest IPC1 score, was found to have high yield stability and is recommended for inclusion in breeding programs for cold climates in Iran.

The genus Polemonium is composed of animal-pollinated herbs found largely in North America. Wide phenotypic variation suggests rapid evolution of floral and vegetative morphology. However, phylogenetic relationships within Polemonium have received little attention. We present a phylogeny of Polemonium based on 1676 Amplified Fragment Length Polymorphisms (AFLPs). We obtained similar topologies through minimum evolution analysis using Nei-Li genetic distances and parsimony analysis. Our analyses supported the monophyly of most species, and indicated that the single annual species, P. micranthum, is sister to all perennial species. Relationships were well resolved among species separated by genetic distances < 0.16. Three well-supported clades each included taxa from one of three species complexes: the P. caeruleum complex, the P. pulcherrimum complex, or the P. viscosum complex. Relationships within clades were generally consistent with earlier systematic work. Exceptions were the inclusion of eastern North American P. reptans within the P. caeruleum clade, inclusion of P. boreale within the P. pulcherrimum clade, and a close relationship between tetraploid P. californicum and diploid P. pulcherrimum subsp. delicatum. Our results indicate that floral traits are quite divergent among close relatives within the genus, and provide a phylogenetic framework for research on adaptation and speciation in Polemonium.