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Thinopyrum intermedium (2n = 6x = 42, JJJSJSStSt) has been hybridized extensively with common wheat and proven to be a valuable germplasm source for improving disease resistance and yield potential of wheat. A novel disease-resistant wheat-Th. intermedium double substitution line X479, carrying 1St(1B) and 4St-4JS (4B), was identified using multi-color non-denaturing fluorescence in situ hybridization (ND-FISH). With the aim of transferring Thinopyrum-specific chromatin to wheat, a total of 573 plants from F2 and F3 progenies of X479 crossed with wheat cultivar MY11 were developed and characterized using sequential ND-FISH with multiple probes. Fifteen types of wheat-Thinopyrum translocation chromosomes were preferentially transmitted in the progenies, and the homozygous wheat-1St, and wheat-4JSL translocation lines were identified using ND-FISH, Oligo-FISH painting and CENH3 immunostaining. The wheat-4JSL translocation lines exhibited high levels of resistance to stripe rust prevalent races in field screening. The gene for stripe rust resistance was found to be physically located on FL0–0.60 of the 4JSL, using deletion lines and specific DNA markers. The new wheat-Th. intermedium translocation lines can be exploited as useful germplasms for wheat improvement.

Thinopyrum intermedium possesses many desirable agronomic traits that make it a valuable genetic source for wheat improvement. The precise identification of individual chromosomes of allohexaploid Th. intermedium is a challenge due to its three sub-genomic constitutions with complex evolutionary ancestries. The non-denaturing fluorescent in situ hybridization (ND-FISH) using tandem-repeat oligos, including Oligo-B11 and Oligo-pDb12H, effectively distinguished the St, J and JS genomes, while Oligo-FISH painting, based on seven oligonucleotide pools derived from collinear regions between barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), was able to identify each linkage group of the Th. intermedium chromosomes. We subsequently established the first karyotype of Th. intermedium with individual chromosome recognition using sequential ND-FISH and Oligo-FISH painting. The chromosome constitutions of 14 wheat–Th. intermedium partial amphiploids and addition lines were characterized. Distinct intergenomic chromosome rearrangements were revealed among Th. intermedium chromosomes in these amphiploids and addition lines. The precisely defined karyotypes of these wheat–Th. intermedium derived lines may be helpful for further study on chromosome evolution, chromatin introgression and wheat breeding programs.

Starch, as the main component of grain in cereals, serves as the major source of calories in staple food and as a raw material for industry. As the technological and digestive properties of starch depend on its content, the management of its components, amylose and amylopectin, is of great importance. The starch properties of wheat grain can be attuned using allelic variations of genes, including granule-bound starch synthase I (GBSS I), or Wx. The tertiary gene pool, including wheatgrass (Thinopyrum) species, provides a wide spectrum of genes-orthologs that can be used to increase the allelic diversity of wheat genes by wide hybridization. Octaploid partial wheat&ndash, wheatgrass hybrids (amphidiploids, WWGHs) combine the complete genome of bread wheat (BBAADD), and a mixed genome from the chromosomes of intermediate wheatgrass (Thinopyrum intermedium, genomic composition JrJrJvsJvsStSt) and tall wheatgrass (Th. ponticum, JJJJJJJsJsJsJs). Thus, WWGHs may carry Wx genes not only of wheat (Wx-B1, Wx-A1 and Wx-D1) but also of wheatgrass origin. We aimed to assess the level of amylose in starch and investigate the polymorphism of Wx genes in 12 accessions of WWGHs. Additionally, we characterized orthologous Wx genes in the genomes of wild wheat-related species involved in the development of the studied WWGHs, Th. intermedium and Th. ponticum, as well as in the putative donors of their subgenomes, bessarabian wheatgrass (Th. bessarabicum, JbJb) and bluebunch wheatgrass (Pseudoroegneria stipifolia, St1St1St2St2). Although no significant differences in amylose content were found between different WWGH accessions, SDS-PAGE demonstrated that at least two WWGHs have an additional band. We sequenced the Wx gene-orthologs in Th. bessarabicum, P. stipifolia, Th. intermedium and Th. ponticum, and developed a WXTH marker that can discriminate the Thinopyrum Wx gene in the wheat background, and localized it to the 7E chromosome in Th. elongatum. Using the WXTH marker we revealed the allelic polymorphism of the Thinopyrum Wx gene in the studied WWGHs. The applicability of Thinopyrum Wx genes in wheat breeding and their effect on starch quality are discussed.

Progress in breeding of intermediate wheatgrass (Thinopyrum intermedium), a perennial grain with environmental benefits, has enabled bran removal. Thus, determination of optimum milling conditions for production of refined flours is warranted. This study explored the effect of tempering conditions on intermediate wheatgrass flour properties, namely composition, color, solvent retention capacity, starch damage, and polyphenol oxidase activity. Changes in flour attributes were evaluated via a 3 &times, 3 &times, 2 factorial design, with factors targeting moisture (comparing un-tempered controls to samples of 12% and 14% target moisture), time (4, 8, and 24 h), and temperature (30 and 45 &deg, C). All investigated parameters were significantly affected by target moisture, however, samples tempered to 12% moisture showed few differences to those tempered to 14%. Similarly, neither tempering time nor temperature exerted pronounced effects on most flour properties, indicating water uptake was fast and not dependent on temperature within the investigated range. Lactic acid retention capacity significantly correlated with ash (r = &minus, 0.739, p &lt, 0.01), insoluble dietary fiber (r = &minus, 0.746, p &lt, 0.01), polyphenol oxidase activity (r = &minus, 0.710, p &lt, 0.01), starch content (r = 0.841, p &lt, 0.01), and starch damage (r = 0.842, p &lt, 0.01), but not with protein (r = 0.357, p &gt, 0.05). In general, tempering resulted in flour with less bran contamination but only minor losses in protein.

Intermediate wheatgrass (IWG, Thinopyrum intermedium, (Host) Barkworth &amp, D.R. Dewey subsp. intermedium, 2n = 6x = 42) is a novel perennial crop currently undergoing domestication efforts. It offers remarkable ecosystem services and yields higher relative to other perennial grain crops. While IWG is mostly resistant to Fusarium head blight (FHB), identifying genomic regions associated with resistance will help protect the crop from potential disease epidemics. An IWG biparental population of 108 individuals was developed by crossing parents differing in their response to FHB and bacterial leaf streak (BLS). The population was screened for disease reaction over three years using isolates collected from IWG plants in St. Paul, Minnesota, USA. Linkage maps representing the 21 IWG chromosomes were constructed from 4622 Single Nucleotide Polymorphism (SNP) markers, with one SNP at every 0.74 cM. Interval mapping identified 15 quantitative trait loci (QTL) associated with FHB resistance and 11 with BLS resistance. Models with two or three QTL combinations reduced FHB disease severity by up to 15%, and BLS by up to 17%. When markers associated with FHB resistance were used as cofactors in genomic selection models, trait predictive ability improved by 24&ndash, 125%. These genomic regions and genetic markers associated with FHB and BLS resistance can also be used to safeguard annual cereal grains through gene introgression and selective breeding.

Ecological intensification of agriculture is a proposed strategy to enhance the production of food while expanding ecosystem services and reducing inputs. Perennial plants that are directly harvested for human food are a novel means of ecological intensification, by potentially providing unprecedented levels of ecological services, such as increased soil carbon and reduced nutrient leaching. However, existing herbaceous perennial plants produce low yields of harvestable seed. Therefore, we initiated a domestication program to improve the grain yield of the perennial intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth & D.R. Dewey). The breeding program has adapted to changing resources and to results from previous generations, with methods becoming more elaborate as the program has matured over six breeding cycles. Average predicted gains from selection accumulated over five cycles were 143, 181 and 60% respectively, for seed yield per head, percent naked seed and mass per seed. We did not detect negative correlations that would indicate simultaneously achieving increased grain yield and sustained perenniality would be particularly difficult. Heritability estimates based on genetic markers were the same or higher than those calculated from a pedigree, indicating that markers have potential to expedite breeding efforts.

Chromosomal translocations in wheat derived from alien species are a valuable source of genetic diversity that have provided increases in resistance to various diseases and improved tolerance to abiotic stresses in wheat. These alien genomic segments can also affect multiple traits, with a concomitant ability to alter yield potential in either a positive or negative fashion. The aim of this work was to characterize the effects on yield of two types of translocations, namely T4-derived translocations from Thinopyrum ponticum, carrying the leaf rust resistance gene Lr19, and the TC14 translocation from Th. intermedium, carrying the barley yellow dwarf virus resistance gene Bdv2, in Australian adapted genetic backgrounds and under Australian conditions. A large range of germplasm was developed by crossing donor sources of the translocations into 24 Australian adapted varieties producing 340 genotypes. Yield trials were conducted in 14 environments to identify effects on yield and yield components. The T4 translocations had a positive effect on yield in one high yielding environment, but negatively affected yield in low-yielding environments. The TC14 translocation was generally benign, however, it was associated with a negative impact on yield and reduced height in two genetic backgrounds. The translocation was also associated with a delayed maturity in several backgrounds. The T4 translocations results were consistent with previously published data, whilst this is the first time that such an investigation has been undertaken on the TC14 translocation. Our data suggests a limited role for each of these translocations in Australia. The T4 translocations may be useful in high yielding environments, such as under irrigation in NSW and in the more productive high rainfall regions of south-eastern Australia. Traits associated with the TC14 translocation, such as BYDV resistance and delayed maturity, would make this translocation useful in BYDV-prone areas that experience a less pronounced terminal drought (e.g., south-eastern Australia).