Academic literature on the topic 'Barley – Breeding; Barley – Genetics'

Spike morphology is a key characteristic in the study of barley genetics, breeding, and domestication. Variation at the six-rowed spike 1 (vrs1) locus is sufficient to control the development and fertility of the lateral spikelet of barley. To study the genetic variation of vrs1 in wild barley (Hordeum vulgare subsp. spontaneum) and cultivated barley (Hordeum vulgare subsp. vulgare), nucleotide sequences of vrs1 were examined in 84 wild barleys (including 10 six-rowed) and 20 cultivated barleys (including 10 six-rowed) from four populations. The length of the vrs1 sequence amplified was 1536 bp. A total of 40 haplotypes were identified in the four populations. The highest nucleotide diversity, haplotype diversity, and per-site nucleotide diversity were observed in the Southwest Asian wild barley population. The nucleotide diversity, number of haplotypes, haplotype diversity, and per-site nucleotide diversity in two-rowed barley were higher than those in six-rowed barley. The phylogenetic analysis of the vrs1 sequences partially separated the six-rowed and the two-rowed barley. The six-rowed barleys were divided into four groups.

In breeding winter malting barley, one recurring strategy is to cross a current preferred spring malting barley to a winter barley. This is because spring malting barleys have the greatest amalgamation of trait qualities desirable for malting and brewing. Spring barley breeding programs can also cycle their material through numerous generations each year—some managing even six—which greatly accelerates combining desirable alleles to generate new lines. In a winter barley breeding program, a single generation per year is the limit when the field environment is used and about two generations per year if vernalization and greenhouse facilities are used. However, crossing the current favored spring malting barley to a winter barley may have its downsides, as winter-hardiness too may be an amalgamation of desirable alleles assembled together that confers the capacity for prolonged cold temperature conditions. In this review I touch on some general criteria that give a variety the distinction of being a malting barley and some of the general trends made in the breeding of spring malting barleys. But the main objective of this review is to pull together different aspects of what we know about winter-hardiness from the seemingly most essential aspect, which is survival in the field, to molecular genetics and gene regulation, and then finish with ideas that might help further our insight for predictability purposes.

This review surveys the current state of taxonomy, origin, and utilization prospects for naked barley. The cultivated barley Hordeum vulgare L. incorporates the covered and naked barley groups. Naked barleys are divided into six-row naked barley (convar. сoeleste (L.) A. Trof.) and two-row naked barley (convar. nudum (L.) A. Trof.). The groups include botanical varieties differing in the structural features of spikes, awns, floret and spikelet glumes, and the color of kernels. The centers of morphogenesis for naked barley are scrutinized employing archeological and paleoethnobotanical data, and the diversity of its forms. Hypotheses on the centers of its origin are discussed using DNA marker data. The main areas of its cultivation are shown, along with possible reasons for such a predominating or exclusive distribution of naked barley in highland areas. Inheritance of nakedness and mechanisms of its manifestation are considered in the context of new data in genetics. The biochemical composition of barley grain in protein, some essential and nonessential amino acids, β-glucans, vitamins, and antioxidants is described. Naked barley is shown to be a valuable source of unique combinations of soluble and insoluble dietary fibers and polysaccharides. The parameters limiting wider distribution of naked barley over the world are emphasized, and breeding efforts that could mitigate them are proposed. Pathogen-resistant naked barley accessions are identified to serve as promising sources for increasing grain yield and quality. Main stages and trends of naked barley breeding are considered and the importance of the VIR global germplasm collection as the richest repository of genetic material for the development of breeding is shown.

Abstract Assessment of genetic diversity using molecular markers is one of the primary and important steps in breeding programs. In this study, genetic diversity of 52 barley lines evaluated using 68 SSR primer pairs and 47 primer pairs produced clear and polymorphic banding pattern. In general, 153 polymorphic alleles detected. The number of observed polymorphic alleles varied from 2 to 9, with an average of 3.26 alleles per locus. Polymorphic Information Content (PIC) ranged from 0.07 to 0.81, with an average of 0.45. In this research, SSR markers differentiated the studied lines efficiently. Using cluster analysis, studied barley lines divided into two groups. Genetic diversity was relatively corresponding with geographical origins, because the lines related to a country somewhat diverged from each other. Two-rowed Iranian and Chinese barleys classified in one subgroup. Also, most six-rowed barleys classified in one subgroup. Association mapping analysis was used to identify candidate genes for drought escape in barley lines and 16 informative markers were identified after which confirmation in other tests could be suitable for marker assisted breeding drought escape.

There have been no plant breeding developments using species from the tertiary genepool of cultivated barley for breeding or genetics since the VIII^th International Barley Genetics Symposium in 2000. Hence, the first part of this review describes progress since 2000 in developing and characterising recombinant lines derived from hybridisations between the sole species in the secondary genepool, Hordeum bulbosum L., and cultivated barley, Hordeum vulgare L. The topics discussed in part I are cytogenetics and molecular analysis of recombinant lines.  

Barley (Hordeum vulgare), first domesticated in the Near East, is a well-studied crop in terms of genetics, genomics, and breeding and qualifies as a model plant for Triticeae research. Recent advances made in barley genomics mainly include the following: (i) rapid accumulation of EST sequence data, (ii) growing number of studies on transcriptome, proteome, and metabolome, (iii) new modeling techniques, (iv) availability of genome-wide knockout collections as well as efficient transformation techniques, and (v) the recently started genome sequencing effort. These developments pave the way for a comprehensive functional analysis and understanding of gene expression networks linked to agronomically important traits. Here, we selectively review important technological developments in barley genomics and related fields and discuss the relevance for understanding genotype-phenotype relationships by using approaches such as genetical genomics and association studies. High-throughput genotyping platforms that have recently become available will allow the construction of high-density genetic maps that will further promote marker-assisted selection as well as physical map construction. Systems biology approaches will further enhance our knowledge and largely increase our abilities to design refined breeding strategies on the basis of detailed molecular physiological knowledge.

Background. Barley is the second cereal crop in Russia in terms of its importance and production volume. It is used for food, feed, and industrial purposes. The production of malting barley in Russia exceeds 1.5 million tons; each year the area under this crop increases by 10–15%, reaching 600,000– 800,000 hectares. Barleys suitable for brewing must have certain physicochemical and technological properties. The main requirements for raw materials are presented in GOST 5060-86 (state standard for malting barley). An important condition for obtaining sustainable harvests is the development and utilization of cultivars resistant to a set of edaphic stressors. The purpose of this work was searching for resistant cultivars for use in targeted breeding.Materials and methods. The material for the study included 161 spring barley cultivars for brewing from the collection of plant genetic resources held by VIR. The laboratory assessment of aluminum tolerance in barley accessions was carried out at the initial phases of plant growth and development, using the method of calculating root and shoot length indices. The tested malting barley was classified into five resistance groups.Results and conclusions. Cultivars resistant to Al3+ ions were identified among different ecogeographic groups of malting barleys. The trait had a wide range of variability in terms of both the root length index (0.17–0.95) and shoot length index (0.47–0.99). Accessions with high resistance to ionic (Al3+) stress can be used in barley breeding targeted at the development of high-yielding malting cultivars most adapted to harmful environmental factors.

Barley is the fourth most important cereal crop and has been domesticated and cultivated for more than 10,000 years. Breeding climate-smart and stress-tolerant cultivars is considered the most suitable way to accelerate barley improvement. However, the conventional breeding framework needs to be changed to facilitate genomics-based breeding of barley. The continuous progress in genomics has opened up new avenues and tools that are promising for making barley breeding more precise and efficient. For instance, reference genome assemblies in combination with germplasm sequencing to delineate breeding have led to the development of more efficient barley cultivars. Genetic analysis, such as QTL mapping and GWAS studies using sequencing approaches, have led to the identification of molecular markers, genomic regions and novel genes associated with the agronomic traits of barley. Furthermore, SNP marker technologies and haplotype-based GWAS have become the most applied methods for supporting molecular breeding in barley. The genetic information is also used for high-efficiency gene editing by means of CRISPR-Cas9 technology, the best example of which is the cv. Golden Promise. In this review, we summarize the genomic databases that have been developed for barley and explain how the genetic resources of the reference genome, the available state-of-the-art bioinformatics tools, and the most recent assembly of a barley pan-genome will boost the genomics-based breeding for barley improvement.

Aim. Establishment of breeding-genetic features of spring barley varieties, their parentals components and hybrids generated via diallel crossing scheme and the efficiency of creating new source material for the crop breeding on their basis. Methods. Breeding and genetic. Statistical (variance, variational, correlation). Responsive. Path analysis. Genetic analyses. Results. Establishing the features of morphological and biological indicators, the level of adaptability, variability, correlation, path analysis, inheritance, combining ability on the basis of varieties and their parent components of spring barley. As a result of the research, the breeding value of varieties as sources of valuable traits was determined and a new source material and a variety of spring barley were created. Conclusions. Selection-genetic features of quantitative traits of spring barley varieties and their parental components have been established. Varieties as sources of valuable traits have been identified. Valuable lines have been created as source material for breeding, as well as barley variety. Keywords: barley, morpho-biological and genetic features of characters, breeding value, line, variety.

The review focuses on recent progress in the breeding of small grain cereals (barley, wheat, oats) for resistance to the barley yellow dwarf virus (BYDV). First, the symptomatology of barley yellow dwarf (BYD) disease is briefly described and the genome of BYDV, its serotypes and mechanisms of its replication and translation in host plants are characterized. Great attention is paid to the description of resistance genes and sources of BYDV resistance that are currently used in some breeding programmes of barley, wheat and oats. In barley, the introduction of the Ryd2 gene into high-yielding cultivars is still desirable. An example of recent success reached in a European programme aimed at a pyramiding of resistance genes is the registration of the Italian feeding barley cultivar Doria, carrying resistance genes Ryd2, rym4 and Rdg1. The release of this cultivar resulted from the cooperation between EICR, Fiorenzuola d’Arda and CRI in Prague-Ruzyně in the field of virus resistance. Finally, some experiments employing transgenic techniques in the construction of resistant plants are mentioned. In conclusion, the advantages and disadvantages of classical breeding methods using crossing and transgenic techniques are compared and newly arising approaches are discussed.

Bibliography: leaves 183-211. This study evaluates the backcross breeding method for the introgression in barley of agronomically important traits into a malting quality background using molecular markers.

Laboratory experiments, genetic simulation, and theoretical analyses were performed to address several objectives related to the use of genetic markers in plant breeding programs. Two software packages were developed: GREGOR provides flexible and efficient computer algorithms for performing genetic simulation experiments, and KIN provides improved methods for estimating coancestry from known pedigrees. Random amplified polymorphic DNA (RAPD) markers were investigated in elite barley lines, and estimates of genetic distance based on RAPD markers were compared to estimates based on coancestry. Both types of estimate can provide information that is useful to breeders and geneticists. Genetic simulation was used to investigate the power, accuracy and precision of several methods that are available for analyzing quantitative trait loci (QTL). In most cases, simplified methods of QTL analysis based on linear regression were similar or superior to more complex methods based on mixture models. Methods for genetic analysis using selective genotyping and pooled DNA were also investigated. These methods may allow precise estimates of the positions of markers and QTL to be made.

Multi environment trials conducted over mapping population are often used to test genotypes in a set of environments that represent the target environmental range. The first part of this work is the evaluation of the ‘Nure’ x ‘Tremois’ double-­‐haploid mapping population, together with an association panel comprising 185 barley varieties representative of the barley germplasm cultivated in the Mediterranean basin. Plant material was tested across eighteen site by year field trials combination, in six countries across the Mediterranean basin. Trials were growth at sites contrasting for natural rainfall (high vs low on the base of past meteorological data) or at the same site with one being rainfed and the other with supplementary irrigation. Trials conducted for two years in each one of the sites and this allowed tocollect a huge data series comprising agronomical traits defining grain yield and yield components, phenological and environmental data, subsequently used to identify genomic regions involved in barley adaptation. The 118 doubled haploid lines of the mapping population were genotyped with Diversity Array Technology® (DaRT) marker assay and subsequently a total of 15 CAPS and SSCP marker for candidate genes involved in phenology regulation and abiotic stress response were added to the linkage map based on DaRT markers. Data collected were firstly used to perform QTLs analysis with composite interval mapping for any environment/ trait combination, results showed eight QTLs for grain yield, days to heading and grain yield components. . The two mostly frequents QTLs for grain yield and days to heading were located on barley chromosome 1H (3 trials), 2H (8 trials) and 5H (5 trials) overlapping respectively HvFT3 gene, the earliness per se locus (eam6/Eps-­‐2) and the vernalization gene Vrn_H1. A further QTL multi-­‐environment analysis was performed and revealed that across the 18 field trials QTL for eam6/Eps-­‐2 (2H) and Vrn-­‐H1 (5H) were commons for days to heading and grain yield. We use all the environmental information collected to check QTLs sensitivities to co-­‐environmental co-­‐variables. Most of significant associations collected were related to temperature and temperature-­‐based variables troughtout the growing cycle. Eam6/Eps-­‐2 showed non-­‐crossover QTL.E interaction, while for Vrn-­‐H1 crossover interactions were revealed. The 185 barley accession were genotyped with 1536 SNPs and data collected for this population for cold resistance in two field trials in Spain an Italy, the first trial was characterized by an exceptional winter, while the second was previously know has frost-­‐prone environment. Results from genome wide association analysis showed 13 positive associations with specific genomic regions. Interestingly several of these QTL were coincident with the position of previously mapped loci for cold tolerance, on chromosomes 2HL, 4HL and 5HL.
Els assajos en localitats múltiplas de poblacions de mapeo s'utilitzen freqüentment per a testar genotips en un conjunt d'ambients representatius de la condicions climàtiques on es volen introduir aquests genotips. La primera part d'això treball ha estat l'avaluació de la població de mapeo ‘Nure x Tremois’ constituïda de 118 de doble haploides d'ordi, juntament amb panell d'associació que comprèn 185 varietats d'ordi representatives del germoplasma conreat en la conca Mediterrània. El material vegetal ha estat assajat en una combinació de divuit camps per any desllorigats en sis països de la conca mediterrània. Els assajos s'han portat a terme en camps amb diferent disponibilitat d'aigua, classificats sobre la base de les dades relatives a les freqüència i quantitat de les precipitacions o en el mateix lloc amb un camp en secà i altre regat. Els assajos es van portar a terme per dos anys en cada localitat i això va permetre la recollida d'un gran volum de dades que comprenen caràcters agronómicos relacionats amb rendiment i components del rendiment, dades fenológicos i ambientals. Aquestes dades es van utilitzar després per a la identificació de regions genomicas involucrades en l'adaptació de l'ordi a l'ambient. Els 118 dobles haploides de la població ‘Nure x Tremois’ es genotiparon amb marcadors DaRT (Diversity Array Technology), després un set de 15 marcadors CAPS I SCCP per a gens candidats involucrats en la regulació de les fases fenológicas van ser afegits al mapa de lligament construït amb els marcadors DaRT. Les dades van ser utilitzats per a fer una anàlisi de QTL amb procediment ‘Composite Interval Mapping’ para cada combinació ambienti/ caràcter. Es van trobar diversos QTLs per rendiment i data d'espigolat i components del rendiment. Els QTL mes freqüents trobats per rendiment i data de floració i components del rendiment estan localitzats en els cromosomes 1H (3 camps), 2H (8 camps) i 5H (5 camps) coincidents respectivament amb HvFT3 locus, eam6/Eps-­‐2 (earliness per se) locus i amb el locus de vernalización Vrn-­‐H1. Una ulterior anàlisi de QTL feta amb el mètode “Multi Environment Trial” ha revelat que els QTL localitzats en el locus eam6/Eps-­‐2 (cromosoma 2H) i Vrn-­‐H1 (cromosoma 5H) són comunes per rendiment i data de floració en els 18 camps d'assaig. Per això utilitzem tots el dades ambientals col·leccionades durant tot el cicle del cultiu per a investigar la sensibilitat de dites QTL a les co-­‐variables ambientals. La majoria de les associacions oposades estan relacionades amb temperatures i variables relacionades amb aquestes. Eam6/Eps-­‐2 mostra una interacció de tipus quantitatiu amb aquestes variables mentre Vrn-­‐H1 mostra una interacció de tipus qualitatiu amb aquestes variables. Les 185 varietats assajades van ser genotipadas amb 185 SNPs i fenotipadas per resistència a fred en dos assajos uneixo a Espanya i altre a Itàlia. El primer assaig va ser caracteritzat per un hivern excepcionalment fred, mentre el d'Itàlia ha estat utilitzat en passat per testar resistència a fred a causa de els hiverns rígids que solen registrar-­‐se en aquesta localitat. Les dades van ser utilitzats per a portar a terme la analisis GWAS “Genome Wide Association Analysis” . Els resultats van permetre identificar 13 regions genomicas involucrades en la resistència a frio. Entre elles tres regions coincideixen amb loci ja mapeados i coneguts per ser involucrats en la resposta a frio en los cromosomes 2HL, 4HL i 5HL.
Los ensayos en localidades múltiplas de poblaciones de mapeo se utilizan frecuentemente para testar genotipos en un conjunto de ambientes representativos de la condiciones climáticas donde se quieren introducir dichos genotipos. La primera parte de esto trabajo ha sido la evaluación de la población de mapeo ‘Nure x Tremois’ constituida de 118 de doble haploides de cebada, junto con panel de asociación que comprende 185 variedades de cebada representativas del germoplasma cultivado en la cuenca Mediterránea. El material vegetal ha sido ensayado en una combinación de dieciocho campos por año dislocados en seis países de la cuenca mediterránea. Los ensayos se han llevado a cabo en campos con diferente disponibilidad de agua, clasificados en base a los datos relativos a las frecuencia y cantidad de las precipitaciones o en el mismo sitio con un campo en secano y otro regado. Los ensayos se llevaron a cabo por dos años en cada localidad y esto permitió la recogida de un gran volumen de datos que comprenden caracteres agronómicos relacionados con rendimiento y componentes del rendimiento, datos fenológicos y ambientales. Dichos datos se utilizaron después para la identificación de regiones genomicas involucradas en la adaptación de la cebada al ambiente. Los 118 dobles haploides de la población ‘Nure x Tremois’ se genotiparon con marcadores DaRT (Diversity Array Technology), después un set de 15 marcadores CAPS Y SCCP para genes candidatos involucrados en la regulación de las fases fenológicas fueron añadidos al mapa de ligamento construido con los marcadores DaRT. Los datos fueron utilizados para hacer una análisis de QTL con procedimiento ‘Composite Interval Mapping’ para cada combinación ambiente/ carácter. Se encontraron varios QTLs por rendimiento y fecha de espigado y componentes del rendimiento. Los QTL mas frecuentes encontrados por rendimiento y fecha de floración y componentes del rendimiento están localizados en los cromosomas 1H (3 campos), 2H (8 campos) y 5H(5 campos) coincidentes respectivamente con HvFT3 locus, eam6/Eps-­‐2 (earliness per se) locus y con el locus de vernalización Vrn-­‐H1. Una ulterior análisis de QTL hecha con el método “Multi Environment Trial” ha revelado que los QTL localizados en el locus eam6/Eps-­‐2 (cromosoma 2H) y Vrn-­‐H1 (cromosoma 5H) son comunes por rendimiento y fecha de floración en los 18 campos de ensayo. Por esto utilizamos todos lo datos ambientales coleccionadas durante todo el ciclo del cultivo para investigar la sensibilidad de dichos QTL a las co-­‐variables ambientales. La mayoría de las asociaciones encontradas están relacionadas con temperaturas y variables relacionadas con estas. Eam6/Eps-­‐2 muestra una interacción de tipo cuantitativo con dichas variables mientras Vrn-­‐H1 muestra una interacción de tipo cualitativo con dichas variables. Las 185 variedades ensayadas fueron genotipadas con 185 SNPs y fenotipadas por resistencia a frío en dos ensayos uno en España y otro en Italia. El primer ensayo fue caracterizado por un invierno excepcionalmente frío, mientras el de Italia ha sido utilizado en pasado por testar resistencia a frío debido a los inviernos rígidos que suelen registrarse en dicha localidad. Los datos fueron utilizados para llevar a cabo la analisis GWAS “Genome Wide Association Analysis”. Los resultados permitieron identificar 13 regiones genomicas involucradas en la resistencia a frio. Entre ellas tres regiones coinciden con loci ya mapeados y conocidos por ser involucrados en la respuesta a frio en los cromosomas 2HL, 4HL y 5HL.

Haploid cereal plants can be regenerated from single pollen grains via the process of anther culture. Anther culture of cereals is of potential use in crop improvement programmes. One problem associated with anther culture of cereal plants is a high incidence of albino individuals which cannot be used in crop breeding schemes. Albinos derived from barley anther culture (albino pollen plants) are severely pigment deficient and from electron microscopy studies appear to possess plastids that are developmentally arrested at a stage prior to the differentiation of proplastids to mature chloroplasts. The aim of the project has been to investigate some of the molecular aspects of albinism in these individuals. In vitro propagation experiments were carried out to find the conditions necessary to improve the growth and maintenance of albino pollen plants with the objective of producing a continuous supply of albino tissue for molecular analysis. However, use of various media containing organic and inorganic supplements including a number of plant growth regulators failed to improve the growth of albino plants. Southern analysis revealed that four out of the five albino plants studied exhibit ptDNA restriction patterns that are different to that expected from the wild type map of the barley plastid genome due to the alteration or deletion of specific ptDNA fragments. One plant appears to contain a major form of ptDNA that has undergone a deletion event removing 75% of all sequences. This confirms that the albino pollen plants examined in this study contain forms of the plastid genome that have undergone structural alteration. I have termed these variant plastid genomes ptDNAs. Most of the albino plants studied appear to contain heterogenous populations of ptDNAs. One albino barley pollen plant appears to possess an intact plastid genome. For all the albinos studied the overall levels of ptDNA are reduced 5-15 fold compared to the levels found in normal green tissues. Northern analyses revealed that the transcripts from the ptDNA genes rbcL and psbD-psbC do not accumulate or are present in albino tissues at 5-10% the level found in seed-derived green shoots. Levels of the plastid encoded 16S and 23S rRNAs are similarly reduced in albino tissues. Further Northern analysis revealed that the abundance of transcripts from the nuclear genes rbcS and cab are present in most albino plants at 10% the level found in normal green tissues. Southern analysis indicated that the nuclear DNA restriction fragments encompassing the cab and rbcS genes in two albino plants had not been altered or deleted during the anther culture process. Analysis of green pollen plants indicated that they contain ptDNA of apparently normal structure and abundance and accumulate transcripts from plastid genes and nuclear genes encoding chloroplast polypeptides to the same levels found in the leaves of light grown seedlings. These results represent the first determination of the levels of photosynthetic gene expression in both albino and green pollen plants.

Abstract Photomorphogenic regulators COP1 (Constitutive Photomorphogenic 1) and HY5 (Elongated Hypocotyl 5) play a key role in plant development by guiding the transition from dark to light growth. In Arabidopsis they are also implicated in the transcriptional control of photolyase genes. Here we characterize the transcript abundance of COP1 and HY5 gene homologues in barley in relation to light-grown conditions and UV-damage response. Etiolated and green 6-day-old seedlings were UV-C irradiated and exposed to light or kept in darkness. The abundance of barley COP1 and HY5 transcripts was assessed by real-time RT-PCR. In etiolated leaves we found several-fold lower levels of COP1 transcripts which reached the levels of the green ones after 1 h of light exposure. Barley HY5 transcripts were very low in the dark-grown seedlings and after 1 h of illumination they increased drastically to levels significantly exceeding those measured in the green leaves. Both genes were upregulated by light in the irradiated plants as well, but to a lesser extent compared with their controls, probably due to the presence of non-repaired DNA damage in the etiolated leaves soon after irradiation. The enhanced transcription of barley COP1 under light is unexpected in view of the well-known function of COP1 as a negative regulator of plant photomorphogenesis but conforms to the positive role reported for AtCOP1 in UV-B signalling. HY5 is recognized as a stimulator of light-inducible genes and our data support such a role for the barley HY5 homologue as well. Our study shows that, in barley seedlings, the regulation of COP1 and HY5 gene expression is achieved through light-positive transcriptional modulation, suggesting that both genes contribute to the de-etiolation phase in barley. According to our knowledge, this is the first quantitation of the COP1 and HY5 mRNAs in barley that also regards the UV-damage response of this crop.

Abstract The plastome is usually considered a highly conserved genome. Compared with the nuclear genome, it is small and has different genetic rules. Through different molecular methods (TILLING, candidate gene sequencing, amplicon massive sequencing and plastome re-sequencing) applied to barley chloroplast mutator (cpm) seedlings, we detected more than 60 polymorphisms affecting a wide variety of plastid genes and several intergenic regions. The genes affected belonged mostly to the plastid genetic machinery and the photosynthetic apparatus, but there were also genes like matK, whose functions are so far not clearly established. Among the isolated mutants, we found the first infA gene mutant in higher plants, two mutants in ycf3 locus and the first psbA gene mutant in barley. The latter is used in breeding barley cultivars where PSII is tolerant to toxic herbicides. Most of the molecular changes were substitutions, and small indels located in microsatellites. However, particular combinations of polymorphisms observed in the rpl23 gene and pseudogene suggest that, besides an increased rate of mutations, an augmented rate of illegitimate recombination also occurred. Although a few substitutions were observed in the mitochondria of cpm plants, we have not yet determined the implications of the cpm for mitochondrial stability. The spectrum of plastome polymorphisms highly suggests that the cpm gene is involved in plastid DNA repair, more precisely taking part in the mismatch repair system. All results show that the cpm mutant is an extraordinary source of plastome variability for plant research and/or plant breeding. This mutant also provides an interesting experimental system in which to investigate the mechanisms responsible for maintaining plastid stability.

Abstract In 1928, the Swedish geneticists Herman Nilsson-Ehle and Åke Gustafsson started to act on their own ideas with the first experiments with induced mutations using diploid barley. They started with X-rays and UV irradiation. Very soon the first chlorophyll mutations were obtained and followed by the first 'vital' mutations Erectoides (ert) (Franckowiak and Lundqvist, 2001). Several other valuable mutations were identified as early maturity, high yielding, lodging resistant and characters with altered plant architecture. The experiments expanded to include other different types of irradiation, followed by chemical mutagenesis starting with mustard gas and concluding with sodium azide. The research brought a wealth of observations of general biological importance, such as the physiological effects of radiation as well as the difference in the mutation spectrum with respect to mutagens. This research was non-commercial, even if some mutants have become of important agronomic value. It peaked in activity during the 1950s to 1980s and, throughout, barley was the main experimental crop. About 12,000 different morphological and physiological mutants with a very broad phenotypic diversity were brought together and are incorporated in the Nordic Genetic Resource Centre (NordGen), Sweden. Several important mutant groups have been analysed in more detail genetically, with regard to mutagen specificity and gene cloning. These are: (i) early maturity mutants (Praematurum); (ii) six-rowed and intermedium-spike mutants; (iii) mutants affecting surface wax coating (Eceriferum); and (iv) mutants affecting rachis spike density (Erectoides). Some of these groups are presented in more detail in this review. Once work with induction of mutations began, it was evident that mutations should regularly be included in breeding programmes of crop plants. In Sweden, direct X-ray induced macro-mutants have been successfully released as cultivars, some of them having been used in combination breeding. Their importance for breeding is discussed in more detail.

The variability of quantitative traits (plant height, spike length, apical internode length, number of spikelets and grains per spike, number of productive tillers per plant) in barley calcaroides mutant of cv. Sonor induced by gamma rays (250 Gy) has been studied. The analysis of variance showed that year condi-tions were mainly responsible (10.59 to 46.96%) for variation of studied traits, followed by the genotype (1.48 to 20.5%) and the interaction of these factors (1.94 to 8.64%), with only one exception for number of grains per spike. Variation of this trait depends mostly on genotype factors. The mean values of all studied traits of mutant form were lower than of Sonor variety. This morphological mutant has a scientific importance.

Original objectives: [a] Screen an array of chickpea and wild annual Cicer germplasm for winter survival. [b] Genetic analysis of winter hardiness in domesticated x wild chickpea crosses. [c] Genetic analysis of vernalization response in domesticated x wild chickpea crosses. [d] Digital expression analysis of a core selection of breeding and germplasm lines of chickpea that differ in winter hardiness and vernalization. [e] Identification of the genes involved in the chickpea winter hardiness and vernalization and construction of gene network controlling these traits. [f] Assessing the phenotypic and genetic correlations between winter hardiness, vernalization response and Ascochyta blight response in chickpea. The complexity of the vernalization response and the inefficiency of our selection experiments (below) required quitting the work on ascochyta response in the framework of this project. Background to the subject: Since its introduction to the Palouse region of WA and Idaho, and the northern Great Plains, chickpea has been a spring rotation legume due to lack of winter hardiness. The short growing season of spring chickpea limits its grain yield and leaves relatively little stubble residue for combating soil erosion. In Israel, chilling temperatures limit pod setting in early springs and narrow the effective reproductive time window of the crop. Winter hardiness and vernalization response of chickpea alleles were lost due to a series of evolutionary bottlenecks; however, such alleles are prevalent in its wild progenitor’s genepool. Major conclusions, solutions, achievements: It appears that both vernalization response and winter hardiness are polygenic traits in the wild-domesticated chickpea genepool. The main conclusion from the fieldwork in Israel is that selection of domesticated winter hardy and vernalization responsive types should be conducted in late flowering and late maturity backgrounds to minimize interference by daylength and temperature response alleles (see our Plant Breeding paper on the subject). The main conclusion from the US winter-hardiness studies is that excellent lines have been identified for germplasm release and continued genetic study. Several of the lines have good seed size and growth habit that will be useful for introgressing winter-hardiness into current chickpea cultivars to develop releases for autumn sowing. We sequenced the transcriptomes and profiled the expression of genes in 87 samples. Differential expression analysis identified a total of 2,452 differentially expressed genes (DEGs) between vernalized plants and control plants, of which 287 were shared between two or more Cicer species studied. We cloned 498 genes controlling vernalization, named CVRN genes. Each of the CVRN genes contributes to flowering date advance (FDA) by 3.85% - 10.71%, but 413 (83%) other genes had negative effects on FDA, while only 83 (17%) had positive effects on FDA, when the plant is exposed to cold temperature. The cloned CVRN genes provide new toolkits and knowledge to develop chickpea cultivars that are suitable for autumn-sowing. Scientific & agricultural implications: Unlike the winter cereals (barley, wheat) or pea, in which a single allelic change may induce a switch from winter to spring habit, we were unable to find any evidence for such major gene action in chickpea. In agricultural terms this means that an alternative strategy must be employed in order to isolate late flowering – ascochyta resistant (winter types) domesticated forms to enable autumn sowing of chickpea in the US Great Plains. An environment was identified in U.S. (eastern Washington) where autumn-sown chickpea production is possible using the levels of winter-hardiness discovered once backcrossed into advanced cultivated material with acceptable agronomic traits. The cloned CVRN genes and identified gene networks significantly advance our understanding of molecular mechanisms underlying plant vernalization in general, and chickpea in particular, and provide a new toolkit for switching chickpea from a spring-sowing to autumn-sowing crop.