Search

Thinopyrum intermedium (2n=6x=42, StStJrJrJvsJvs) is resistant or tolerant to biotic and abiotic stresses, making it suitable for developing perennial crops and forage. Through five cycles of selection, we developed 24 perennial wheatgrass lines, designated 19HSC-Q and 20HSC-Z, by crossing wheat-Th. intermedium partial amphiploids with Th. intermedium. The cold resistance, morphological performance, chromosome composition, and yield components of these perennial lines were investigated from 2019 to 2022. Six lines of 19HSC-Q had higher 1,000-kernel weight, grains per spike, and tiller number than Th. intermedium, as well as surviving -30°C in winter. Lines 19HSC-Q14, 19HSCQ18, and 19HSC-Q20 had the best performances for grain number per spike and 1,000-kernel weight. The 20HSC-Z lines, 20HSC-Z1, 20HSC-Z2, and 20HSC-Z3, were able to survive in the cold winter in Harbin and had been grown for two years. Sequential multicolor GISH analysis revealed that the Jvs subgenome of Th. intermedium were divided into two karyotypes, three pairs of type-I Jvs chromosomes and four pairs of type-II Jvs chromosomes. Both Th. intermedium and the 24 advanced perennial wheatgrass lines had similar chromosome compositions, but the translocations among subgenome chromosomes were detected in some lines with prominent agronomic traits, such as 19HSC-Q11, 19HSC-Q14, 19HSC-Q18, 19HSC-Q20, and the three 20HSC-Z lines. The chromosome aberrations were distinguished into two types: the large fragment translocation with St-Jr, Jvs-St, Jr-IIJvs, and Jvs-Jr and the small fragment introgression of Jr-St, St-IJvs, and Jvs-Jr. These chromosomal variations can be used to further analyze the relationship between the subgenomes and phenotypes of Th. intermedium. The results of this study provide valuable materials for the next selection cycle of cold-resistant perennial wheatgrass. [ABSTRACT FROM AUTHOR]

Wheat stripe rust is a destructive disease in many cool and temperate regions around the world. Exploiting novel sources of resistance can provide wheat cultivars with robust and durable resistance to stripe rust. The wheat-Thinopyrum intermedium addition line TAI-14 was proven to carry a stripe rust resistance gene (named as YrT14) on the alien Th. intermedium chromosome. In order to transfer the resistance gene to wheat, wheat-Th. intermedium translocation lines were created by irradiating the pollen of the line TAI-14. We totally obtained 153 wheat-Th. intermedium translocation lines, among which the long alien segmental translocation line Zhongke 78 and the intercalary translocation line Zhongke 15 not only showed good integrated agronomic traits but also were identified as highly resistant to stripe rust in both seedling and adult plant stages. The alien chromatin in Zhongke 15 was identified as an insertion into the satellite of chromosome 6B, a type of translocation never reported before in chromosome engineering. By screening Simple Sequence Repeat (SSR) and Expressed Sequence Tag (EST) markers as well as the markers developed from RNA-sequencing (RNA-Seq) data, 14 markers were identified specific for the alien chromosome and a physical map was constructed. Both Zhongke 78 and Zhongke 15 could be used as a novel source of stripe rust resistance for wheat breeding, and the linked marker T14K50 can be used for molecular marker-assisted breeding. Finally, based on the karyotype, reaction to stripe rust, and genome resequencing data of different wheat-Th. intermedium translocation lines, the stripe rust resistance gene YrT14 was located to an 88.1 Mb interval from 636.7 to 724.8 Mb on Th. intermedium chromosome 19 corresponding to 7J or 7Js. [ABSTRACT FROM AUTHOR]

Thinopyrum intermedium (JJJsJsStSt, 2n = 6x = 42), a member of tertiary gene pool of hexaploid wheat (Triticum aestivum L., AABBDD, 2n = 6x = 42), provides several beneficial genes for wheat improvement. In this study, line CH51 was developed from the BC1F8 progeny of a partial wheat-Th. intermedium amphiploid TAI8335 (2n = 56) and wheat cultivar (cv.) Jintai 170. Somatic metaphase chromosome counting showed that CH51 had stable 42 chromosomes. Genomic in situ hybridization (GISH) analysis showed that CH51 had 40 wheat chromosomes and two Th. intermedium chromosomes involving translocation between Js- and St-genome chromosomes. Nondenaturing fluorescence in situ hybridization (ND-FISH) analysis revealed that CH51 lacked a pair of wheat chromosome 6B. Wheat 55K SNP array analysis verified that chromosome 6B had the highest percentage of missing SNP loci in both CH51 and Chinese Spring (CS) nullisomic 6B-tetrasomic 6D (CS-N6BT6D) and had the highest percentage of polymorphic SNP loci between CH51 and cv. Jintai 170. We identified that CH51 was a wheat-Th. intermedium T6StS.6JsL (6B) disomic substitution line. Disease resistance assessment showed that CH51 exhibited high levels of resistance to the prevalent Chinese leaf rust and stripe rust races in the field. Therefore, the newly developed line CH51 can be utilized as a potential germplasm in wheat disease resistance breeding. [ABSTRACT FROM AUTHOR]

Thinopyrum intermedium (2n = 6x = 42, JJJSJSStSt) is one of the important resources for the wheat improvement. So far, a few Th. intermedium (Thi)-specific molecular markers have been reported, but the number is far from enough to meet the need of identifying alien fragments in wheat-Th. intermedium hybrids. In this study, 5,877,409 contigs were assembled using the Th. intermedium genotyping-by-sequencing (GBS) data. We obtained 5,452 non-redundant contigs containing mapped Thi-GBS markers with less than 20% similarity to the wheat genome and developed 2,019 sequence-tagged site (STS) molecular markers. Among the markers designed, 745 Thi-specific markers with amplification products in Th. intermedium but not in eight wheat landraces were further selected. The distribution of these markers in different homologous groups of Th. intermedium varied from 47 (7/12/28 on 6J/6St/6JS) to 183 (54/62/67 on 7J/7St/7JS). Furthermore, the effectiveness of these Thi-specific markers was verified using wheat-Th. intermedium partial amphidiploids, addition lines, substitution lines, and translocation lines. Markers developed in this study provide a convenient, rapid, reliable, and economical method for identifying Th. intermedium chromosomes in wheat. In addition, this set of Thi-specific markers can also be used to estimate genetic and physical locations of Th. intermedium chromatin in the introgression lines, thus providing valuable information for follow-up studies such as alien gene mining.

Thinopyrum intermedium (2 n = 6 x = 42, JJJSJSStSt) is one of the important resources for the wheat improvement. So far, a few Th. intermedium (Thi)-specific molecular markers have been reported, but the number is far from enough to meet the need of identifying alien fragments in wheat- Th. intermedium hybrids. In this study, 5,877,409 contigs were assembled using the Th. intermedium genotyping-by-sequencing (GBS) data. We obtained 5,452 non-redundant contigs containing mapped Thi -GBS markers with less than 20% similarity to the wheat genome and developed 2,019 sequence-tagged site (STS) molecular markers. Among the markers designed, 745 Thi -specific markers with amplification products in Th. intermedium but not in eight wheat landraces were further selected. The distribution of these markers in different homologous groups of Th. intermedium varied from 47 (7/12/28 on 6J/6St/6JS) to 183 (54/62/67 on 7J/7St/7JS). Furthermore, the effectiveness of these Thi -specific markers was verified using wheat- Th. intermedium partial amphidiploids, addition lines, substitution lines, and translocation lines. Markers developed in this study provide a convenient, rapid, reliable, and economical method for identifying Th. intermedium chromosomes in wheat. In addition, this set of Thi -specific markers can also be used to estimate genetic and physical locations of Th. intermedium chromatin in the introgression lines, thus providing valuable information for follow-up studies such as alien gene mining. [ABSTRACT FROM AUTHOR]

Perennial wheat is considered to be a practical way to increase the flexibility and profitability of sustainable agricultural system, as it can be either a forage grass or a grain crop. Four perennial wheat lines SX12-480, SX12-787, SX12-1150, and SX12-1269 were developed from a series of interspecific crosses between common wheat (Triticum aestivum, 2n = 42) or durum wheat (T. turgidum var. durum, 2n = 28) and the intermediate wheatgrass (Thinopyrum intermedium, 2n = 42). These lines were characterized by the vigorous regrowth for at least 3 years. The one- and 2-year-old plants had higher grain yield potential than the 3-year-old perennial plants. The decline of grain yield was associated with plant age-related effects on yield components. The perennial wheat lines were all resistant to both Heterodera avenae and H. filipjevi, the two distinct cereal cyst nematode species that occur in China, except that line SX12-787 exhibited moderate resistance only to H. avenae. The dual-purpose perennial wheat lines were evaluated for quality values of both defoliated grass and harvested grains in the form of amino acid profile, mineral concentration, and contents of protein and fiber. Difference in the quality profile was observed between the perennial lines. These perennial lines had an overall improved quality levels over those of the perennial wheat control Montana-2 (T. turgidum × Th. intermedium) and the annual wheat cultivar Jinchun 9. The amplification profiles of the molecular markers provided molecular evidence for the introgression of alien chromatin. Genomic in situ hybridization detected 16, 14, 14, and 12 Th. intermedium chromosomes in lines SX12-480 (2n = 48), SX12-787 (2n = 56), SX12-1150 (2n = 56), and SX12-1269 (2n = 54), respectively, in addition to either 32 or the complete set of wheat chromosomes. The four perennial wheat-Th. intermedium lines described here provide valuable sources of perennial wheat for the dual-purpose application of both grain and forage.

Cold-hardy perennial wheatgrass plays an important role in the use of barren land for farming, soil and water conservation, variety improvement, and also for increasing grass yield. By crossing octoploid tritelytrigia (2n = 8x = 56, AABBDDEE) with Thinopyrum intermedium (2n = 6x = 42, StStJJJSJS), we developed 34 lines of perennial wheatgrass from F1 to F6 generations, which had vigorous regrowth and cold hardiness. The cold-hardy, perennial wheatgrass lines were well-adapted to the cold environment and developed root and rhizomes, with a longevity between 5 and 11 years and a better seed set. Some of them maintained wheat chromosomes beneficial for breeding perennial wheat. Molecular cytogenetic analysis demonstrated that the Th. intermedium chromosomes contributed the most to the synthetic genome of the wheatgrass hybrids and were associated with the perennial growth habit and winter hardiness. They were also preferentially maintained and transmitted to the progenies. Some wheat chromosomes were also transmitted from the F1 to F6 generations, although they were eliminated in each life cycle of the wheatgrass hybrids. The numbers of wheat and Th. intermedium chromosomes affected seed set and perennial growth habit. Seed set increased with the establishment of a more balanced genomic constitution in later generations. The cold-hardy and perennial wheatgrass lines were produced, which can be the starting point of domestication effort aimed at producing well-adapted ground cover plants under extreme environments.

Perennial wheat is considered to be a practical way to increase the flexibility and profitability of sustainable agricultural system, as it can be either a forage grass or a grain crop. Four perennial wheat lines SX12-480, SX12-787, SX12-1150, and SX12-1269 were developed from a series of interspecific crosses between common wheat (Triticum aestivum , 2n = 42) or durum wheat (T. turgidum var. durum , 2n = 28) and the intermediate wheatgrass (Thinopyrum intermedium , 2n = 42). These lines were characterized by the vigorous regrowth for at least 3 years. The one- and 2-year-old plants had higher grain yield potential than the 3-year-old perennial plants. The decline of grain yield was associated with plant age-related effects on yield components. The perennial wheat lines were all resistant to both Heterodera avenae and H. filipjevi , the two distinct cereal cyst nematode species that occur in China, except that line SX12-787 exhibited moderate resistance only to H. avenae. The dual-purpose perennial wheat lines were evaluated for quality values of both defoliated grass and harvested grains in the form of amino acid profile, mineral concentration, and contents of protein and fiber. Difference in the quality profile was observed between the perennial lines. These perennial lines had an overall improved quality levels over those of the perennial wheat control Montana-2 (T. turgidum × Th. intermedium) and the annual wheat cultivar Jinchun 9. The amplification profiles of the molecular markers provided molecular evidence for the introgression of alien chromatin. Genomic in situ hybridization detected 16, 14, 14, and 12 Th. intermedium chromosomes in lines SX12-480 (2n = 48), SX12-787 (2n = 56), SX12-1150 (2n = 56), and SX12-1269 (2n = 54), respectively, in addition to either 32 or the complete set of wheat chromosomes. The four perennial wheat- Th. intermedium lines described here provide valuable sources of perennial wheat for the dual-purpose application of both grain and forage. [ABSTRACT FROM AUTHOR]

Cold-hardy perennial wheatgrass plays an important role in the use of barren land for farming, soil and water conservation, variety improvement, and also for increasing grass yield. By crossing octoploid tritelytrigia (2n = 8x = 56, AABBDDEE) with Thinopyrum intermedium (2n = 6x = 42, StStJJJ S J S ), we developed 34 lines of perennial wheatgrass from F1 to F6 generations, which had vigorous regrowth and cold hardiness. The cold-hardy, perennial wheatgrass lines were well-adapted to the cold environment and developed root and rhizomes, with a longevity between 5 and 11 years and a better seed set. Some of them maintained wheat chromosomes beneficial for breeding perennial wheat. Molecular cytogenetic analysis demonstrated that the Th. intermedium chromosomes contributed the most to the synthetic genome of the wheatgrass hybrids and were associated with the perennial growth habit and winter hardiness. They were also preferentially maintained and transmitted to the progenies. Some wheat chromosomes were also transmitted from the F1 to F6 generations, although they were eliminated in each life cycle of the wheatgrass hybrids. The numbers of wheat and Th. intermedium chromosomes affected seed set and perennial growth habit. Seed set increased with the establishment of a more balanced genomic constitution in later generations. The cold-hardy and perennial wheatgrass lines were produced, which can be the starting point of domestication effort aimed at producing well-adapted ground cover plants under extreme environments. [ABSTRACT FROM AUTHOR]