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Within temperate climates the frequency and severity of high and low temperature stresses vary with continentality. The current study reports on the assessment of the performance of 49 barley cultivars across four environments. The cultivars stem from 50 years of breeding activities in Romania and Italy, in two temperate climates that differ in continentality. The plants were phenotyped through stress monitoring, measurements of yield and yield related traits as well as laboratory stress tolerance tests. Genotypes for alleles of vernalisation and photoperiod genes were determined. These genes were significantly associated with frost damage in the field and frost tolerance in laboratory tests. Grain yield (GY) was more closely correlated with the number of grain sinks than with the degree of grain filling indicating major limitations in the vegetative growth phase and during grain initiation. High temperature stress during the grain filling phase significantly reduced GY. Frost damage due to freezing temperatures below -10 °C when plants were not protected by snow cover significantly reduced GY of sensitive cultivars. The characterisation of environmental cues that cause stresses with yield penalties as well as the susceptibility of genetically different cultivars lay the ground for future targeted selection. [ABSTRACT FROM AUTHOR]

A better understanding of the developmental plan of a cereal spike is of relevance when designing the plant for the future, in which innovative traits can be implemented through pre-breeding strategies. Barley developmental mutants can be a Mendelian solution for identifying genes controlling key steps in the establishment of the spike morphology. Among cereals, barley (Hordeum vulgare L.) is one of the best investigated crop plants and is a model species for the Triticeae tribe, thanks to several characteristics, including, among others, its adaptability to a wide range of environments, its diploid genome, and its self-pollinating mating system, as well as the availability of its genome sequence and a wide array of genomic resources. Among them, large collections of natural and induced mutants have been developed since the 1920s, with the aim of understanding developmental and physiological processes and exploiting mutation breeding in crop improvement. The collections are not only comprehensive in terms of single Mendelian spike mutants, but with regards to double and triple mutants derived from crosses between simple mutants, as well as near isogenic lines (NILs) that are useful for genetic studies. In recent years the integration of the most advanced omic technologies with historical mutation-genetics research has helped in the isolation and validation of some of the genes involved in spike development. New interrogatives have raised the question about how the behavior of a single developmental gene in different genetic backgrounds can help in understanding phenomena like expressivity, penetrance, phenotypic plasticity and instability. In this paper, some genetic and epigenetic studies on this topic are reviewed. [ABSTRACT FROM AUTHOR]

Frost tolerance is the main component of winter hardiness for cereals and is largely dependent on the plant's ability to cold acclimate by means of a slow adaptive response induced by low, non-freezing temperatures. In the present work, a Genome-Wide Association mapping study has been performed, looking for the genetic determinants of frost tolerance in a panel of European spring 2-row barley cultivars. Frost damage was evaluated by measuring chlorophyll fluorescence (Fv/Fm) and membrane integrity (Electrolyte Leakage) and considerable variation for this trait was discovered. Genetic association of the trait was sought with >5000 gene-based mapped SNP markers using a Mixed Linear Model approach. A simple genetic architecture was revealed for frost tolerance in this population, with a principal role for the Fr-H1/Vrn-H1 and Fr-H2 loci already detected in previous linkage and association mapping studies. Allelic richness might exist at these loci, not only between winter and spring barley, but also within the spring germplasm, thus offering the opportunity for future development of new spring barley lines with improved resilience in the face of emerging climate change. [ABSTRACT FROM AUTHOR]