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1.
Accurate and reliable means for identification are necessary to assess the discrimination between landraces of tetraploid wheat [T.␣turgidum L. subsp. durum (Desf.) Husn.] and hexaploid wheat (T. aestivum L. em. Thell.). In Afghanistan, farmers usually cultivate mixed landraces, and thus distinction between bread and durum is difficult. A set of 18 microsatellites derived from the DuPont EST-database were used to describe genetic diversity in a sample of 82 Afghan wheat landraces. A total of 101 alleles were detected, with allele number per locus ranging from 2 to 13, and a mean allele number of 6.31. The percentage of polymorphic loci was 89%. The EST-SSRs markers showed different level of gene diversity: the highest Polymorphism Information Content value (0.921) was observed with DuPw 221. Our results demonstrated that with a reasonable number of expressed sequences target microsatellites (EST-SSRs) it is possible to discriminate between T. durum and T. aestivum species of wheat germplasm. Our results showed that EST-databases could be a useful source for species-specific markers and have the potential for new genic microsatellites markers that could enhance screening germplasm in gene banks.  相似文献   

2.
Thirty-four durum wheat cultivars representing the Tunisian durum (Triticum durum Desf.) wheat collection and seven wild species of wheat relatives (Triticum turgidum L., T. dicoccon Schrank., T. dicoccoides (Körn) Schweinf., T. araraticum Jakubz., T. monococcum L., Aegilops geniculata Roth, and Aegilops ventricosa Tausch) were analysed with amplified fragment length polymorphism (AFLP) and microsatellite (SSR) markers. Both marker systems used were able to differentiate durum wheat cultivars from the wild relatives and to specifically fingerprint each of the genotypes studied. However, the two marker systems differed in the amount of detected polymorphisms. The 15 SSR markers were highly polymorphic across all the genotypes. The total number of amplified fragments was 156 and the number of alleles per locus ranged from 3 to 24 with an average of 10.4. Two SSR markers alone, Xwms47 and Xwms268, were sufficient to distinguish all 34 durum wheat genotypes. The five AFLP primer pair combinations analysed yielded a total of 293 bands, of which 31% were polymorphic. The highest polymorphic information content (PIC) value was observed for SSRs (0.68) while the highest marker index (MI) value was for AFLPs (7.16) reflecting the hypervariability of the first and the distinctive nature of the second system. For durum wheat cultivars, the genetic similarity values varied between 31.3 and 81% for AFLPs (with an average of 54.2%), and between 3.6 and 72.7% for SSRs (with an average of 19.9%). The rank correlation between the two marker systems was moderate, with r = 0.57, but highly significant. Based on SSR markers, highest genetic similarity (GS) values were observed within the modern cultivars (37.3%), while the old cultivars showed a low level of GS (19.9%). Moreover, the modern cultivars showed low PIC and MI values. UPGMA Cluster analysis based on the combined AFLP and SSR data separated the wild wheat species from the durum wheat cultivars. The modern cultivars were separated from the old cultivars and form a distinct group.  相似文献   

3.
Genetic diversity among some important Syrian wheat cultivars was estimated using Amplified Fragment Length Polymorphism (AFLP) markers. Five Triticum aestivum L. and 10 Triticum turgidum ssp. durum were analyzed with 11 EcoRI–MseI primer pair combinations. Of the approximately 525 detected AFLP markers, only 46.67% were polymorphic. Cluster analysis with the entire AFLP data divided all cultivars into two major groups reflecting their origins. The first one contained T. aestivum L. cultivars, and the T. turgidum ssp. durum cultivars and landraces were grouped in the second. Narrow genetic diversity among all cultivars was detected with an average genetic similarity of 0.884. The lowest similarity index (0.9) was found between Cham5 and Hamary (durum wheat), whereas this value was 0.93 between Salamony and Bouhouth 4 (T. aestivum L.). The narrow genetic diversity level indicates that these genotypes could be originated from the same source. AFLP analysis provides crucial information for studying genetic variation among wheat cultivars and provides important information for plant improvement.  相似文献   

4.
Worldwide, nearly 20 times more common wheat (Triticum aestivum) is produced than durum wheat (T. turgidum subsp. durum). Durum wheat is predominately milled into coarse semolina owing to the extreme hardness of the kernels. Semolina, lacking the versatility of traditional flour, is used primarily in the production of pasta. The puroindoline genes, responsible for kernel softness in wheat, have been introduced into durum via homoeologous recombination. The objective of this study was to determine what impact the introgression of the puroindoline genes, and subsequent expression of the soft kernel phenotype, had on the milling properties and flour characteristics of durum wheat. Three grain lots of Soft Svevo and one of Soft Alzada, two soft‐kernel back‐cross derived durum varieties, were milled into flour on the modified Quadrumat Senior laboratory mill at 13, 14, and 16% temper levels. Samples of Svevo (a durum wheat and recurrent parent of Soft Svevo), Xerpha (a soft white winter wheat), and Expresso (a hard red spring wheat) were included as comparisons. Soft Svevo and Soft Alzada exhibited dramatically lower single‐kernel characterization system kernel hardness than the other samples. Soft Svevo and Soft Alzada had high break flour yields, similar to the common wheat samples, especially the soft hexaploid wheat, and markedly greater than the durum samples. Overall, Soft Svevo and Soft Alzada exhibited milling properties and flour quality comparable, if not superior, to those of common wheat.  相似文献   

5.
Durum wheat, Triticum durum Desf., is reportedly more sensitive to aluminum (Al) toxicity in acid soils than hexaploid wheat, Triticum aestivum L. em. Thell. Aluminum‐tolerant genotypes would permit more widespread use of this species where it is desired, but not grown, because of acid soil constraints. Durum wheat germplasm has not been adequately screened for acid soil (Al) tolerance. Fifteen lines of durum wheat were grown for 28 days in greenhouse pots of acid, Al‐toxic Tatum subsoil at pH 4.5, and non‐toxic soil at pH 6.0. Aluminum‐tolerant Atlas 66 and sensitive Scout 66 hexaploid wheats were also included as standards. Based on relative shoot and root dry weight (wt. at pH 4.5/wt. at pH 6.0 X 100), durum entries differed significantly in tolerance to the acid soil. Relative shoot dry weight alone was an acceptable indicator of acid soil tolerance. Relative dry weights ranged from 55.1 to 15.5% for shoots and from 107 to 15.8% for roots. Durum lines PI 195726 (Ethiopia) and PI 193922 (Brazil) were significantly more tolerant than all other entries, even the Al‐tolerant, hexaploid Atlas 66 standard. Hence, these two lines have potential for direct use on acid soils or as breeding materials for use in developing greater Al tolerance in durum wheat. Unexpectedly, the range of acid soil tolerance available in durum wheat appears comparable to that in the hexaploid species. Hence, additional screening of durum wheat germplasm for acid soil (Al) tolerance appears warranted. Durum lines showing least tolerance to the acid soil included PI 322716 (Mexico), PI 264991 (Greece), PI 478306 (Washington State, USA), and PI 345040 (Yugoslavia). The Al‐sensitive Scout 66 standard was as sensitive as the most sensitive durum lines. Concentrations of Al and phosphorus were significantly higher in shoots of acid soil sensitive than in those of tolerant lines, and these values exceeded those reported to cause Al and phosphorus (P) toxicities in wheat and barley.  相似文献   

6.
Durum wheat (Triticum turgidum L. var durum) is a species that accumulates cadmium (Cd). Durum wheat cultivars differ in their absorption ability of Cd; therefore, identifying and selecting genetic material with low Cd accumulation reduces human exposure to this toxic element. In the present study, Cd concentration was evaluated in three Chilean durum wheat cultivars (Llareta-INIA, Corcolén-INIA, and Lleuque-INIA) grown in four Chilean locations with varying concentrations of Cd in soils. The objective of this study was to evaluate the response of these durum wheat cultivars to different doses of cadmium in terms of grain yield; Cd concentration in different plant tissues (grain, straw, roots); soil Cd concentration was also evaluated. Results show that grain yield was not affected by soil Cd; differences in Cd concentration in plant tissues were generally associated with location, cultivar, and soil Cd concentration. Grain Cd concentration in all three cultivars was classified in the low accumulation category for this metal; ‘Lleuque-INIA’ noted as having a very low accumulation.  相似文献   

7.
Hexaploid bread wheat (Triticum aestivum L. ssp. aestivum) is assumed to have originated by natural hybridization between cultivated tetraploid Triticum turgidum L. and wild diploid Aegilops tauschii Coss. This scenario is broadly accepted, but very little is known about the ecological aspects of bread wheat evolution. In this study, we examined whether T. turgidum cultivation still is associated with weedy Ae. tauschii in today’s Middle Eastern agroecosystems. We surveyed current distributions of T. turgidum and Ae. tauschii in northern Iran and searched for sites where these two species coexist. Ae. tauschii occurred widely in the study area, whereas cultivated T. turgidum had a narrow distribution range. Traditional durum wheat (T. turgidum ssp. durum (Desf.) Husn.) cultivation associated with weedy Ae. tauschii was observed in the Alamut and Deylaman-Barrehsar districts of the central Alborz Mountain region. The results of our field survey showed that the T. turgidum–Ae. tauschii association hypothesized in the theory of bread wheat evolution still exists in the area where bread wheat probably evolved.  相似文献   

8.
Hard red spring wheat (Triticum aestivum L. subsp. aestivum) and durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) have both been selected for dryland yield potential and high grain protein, although end uses of flour are different. For this study, 14 tetraploid and 10 hexaploid lines were derived from crosses between tetraploid durum wheat and hexaploid hard red spring wheat. Our objective was to determine the impact of genetic exchange between the two classes on agronomic and quality attributes of derived progeny lines. Yield potential of both the tetraploid and hexaploid progeny was lower than the parental types. Polyphenol oxidase levels were higher by almost twofold in the hexaploid group. The tetraploid progeny group had better noodle color than did the hexaploid group. Bread quality of hexaploid group was superior, with loaf volume 362 cm3 higher than that of tetraploid progeny group. In general, the presence of durum wheat genes in the derived hexaploid lines had little impact on most quality traits. The presence or absence of the D genome tended to be the major influence on end use quality traits. Our results suggest that genetic exchange between the two groups has a small effect on end use quality, but low yield potential in the progeny suggests obtaining desirable genetic combinations for plant improvement may be challenging.  相似文献   

9.
Nitrification and ammonia volatility are two important impediments to nitrogen (N) use efficiency and crop uptake around the world. Nutrisphere® is a relatively new product whose manufacturer claims both nitrification and urea volatilization inhibiting properties. Urea coated with Nutrisphere is and the resulting fertilizer is called Nutrisphere®-N urea, or Nutrisphere-N (NSN). Eight field studies on spring (Triticum aestivum L.) or durum [T. turgidum L. subsp duram (Desf.) Husn.] wheat in North Dakota, three field studies in Mississippi/Arkansas on rice (Oryza sativa L.), four laboratory experiments in North Dakota and one in Arkansas were conducted to determine the nitrification and urea volatilization inhibiting ability of NSN compared with urea alone. Results of field and laboratory experiments revealed that the product has no nitrification or urea volatilization inhibiting properties at the recommended rates and spring wheat and rice did not benefit from the application of NSN to urea.  相似文献   

10.
Little is known about genetic diversity and geographic origin of wheat landraces from Oman, an ancient area of wheat cultivation. The objectives of this study were to investigate the genetic relationships and levels of diversity of six wheat landraces collected in Oman with a set of 30 evenly distributed SSR markers. The total gene diversity, (HT), conserved in the three durum wheat (Triticum durum desf.) landraces (HT = 0.46) was higher than in the three bread wheat (Triticum aestivum L.) landraces (HT = 0.37), which were similar to Turkish and Mexican bread wheat landraces calculated in previous studies. Genetic variation partitioning (GST) showed that variation was mainly distributed within rather than among the durum (GST = 0.30) and bread wheat (GST = 0.19) landraces. Based on modified Rogers’ distance (MRD), the durum and bread wheat landraces were distinct from each other except for a few individuals according to principal coordinate analysis (PCoA). One bread wheat landrace (Greda) was separated into two distinct sub-populations. A joint cluster analysis with other landraces of worldwide origin revealed that Omani bread wheat landraces were different from other landraces. However, two landraces from Pakistan were grouped somewhat closer to Omani landraces indicating a possible, previously unknown relationship. Implications of these results for future wheat landrace collection, evaluation and conservation are discussed.  相似文献   

11.
Mutation of the gene coding for the granule bound starch synthase (waxy protein) leads to reduced amylose content in cereal endosperm. Durum wheat (Triticum turgidum L. var. durum) has one waxy locus in each of its two genomes. Full waxy durum wheat is produced when both genomes carry the waxy null alleles. When only one locus is mutated, partial waxy durum wheat is obtained. Partial and full waxy near‐isogenic lines of durum wheat developed by a breeding program were analyzed as to their quality characteristics. Amylose was largely eliminated in full waxy lines; however, no reduction in amylose content was detected in partial waxy lines. The waxy mutation did not affect grain yield, kernel size, or kernel hardness. Full waxy durum lines had higher kernel ash content, α‐amylase activity, and a unique nonvitreous kernel appearance. Protein quality, as evaluated by SDS microsedimentation value, gluten index, and wet gluten was slightly lower in the full waxy lines than in the other genotypes. However, comparisons with current cultivars indicated that protein quality of all derived lines remained in the range of strong gluten cultivars. Semolina yield was lowered by the waxy mutations due to lower friability that resulted in less complete separation of the endosperm from the bran. Waxy semolina was more sensitive to mechanical damage during milling, but modified tempering and milling conditions may limit the damage. Overall, quality characteristics of waxy durum grain were satisfactory and suitable for application testing.  相似文献   

12.
A greenhouse experiment was conducted with three doses of boron (0, 1, and 10 mg B kg?1 in the form of boric acid (H3BO3). Durum wheat (Triticum durum L. cv: Çakmak-79) and bread wheat (Triticum aestivum L. cv: Gerek-79) cultivars were used as plant material. B toxicity symptoms strongly appeared in durum wheat compared to bread wheat. Applications of B at 1.0 mg B kg?1 stimulated and increased the dry weights of both the cultivars, while high level B application (i.e., 10 mg B kg?1) depressed and decreased the dry weights significantly. B concentration and uptake in the leaf tip were increased with an increase in B application, whereas calcium (Ca) concentration and uptake were decreased in both the cultivars. It was observed that a substantial amount of B was accumulated in the plant cell wall. As similar to leaf tips, B concentrations in the cell wall also increased with B application, whereas Ca concentration was decreased.  相似文献   

13.
《Cereal Chemistry》2017,94(2):215-222
Durum wheat (Triticum turgidum subsp. durum ) production worldwide is substantially less than that of common wheat (T. aestivum ). Durum kernels are extremely hard; thus, most durum wheat is milled into semolina, which has limited utilization. Soft kernel durum wheat was created by introgression of the puroindoline genes via homoeologous recombination. The objective of this study was to determine the effects of the puroindoline genes and soft kernel texture on flour, water absorption, rheology, and baking quality of durum wheat. Soft Svevo and Soft Alzada, back‐cross derivatives of the durum varieties Svevo and Alzada, were compared with Svevo, a hard durum wheat, Xerpha, a soft white winter wheat, and Expresso, a hard red spring wheat. Soft Svevo and Soft Alzada exhibited soft kernel texture; low water, sodium carbonate, and sucrose solvent retention capacities (SRCs); and reduced dough water absorptions similar to soft wheat. These results indicate a pronounced effect of the puroindolines. Conversely, SDS flour sedimentation volume and lactic acid SRC of the soft durum samples were more similar to the Svevo hard durum and Expresso samples, indicating much less effect of kernel softness on protein strength measurements. Alveograph results were influenced by the inherent differences in water absorption properties of the different flours and their genetic background (e.g., W and P were markedly reduced in the Soft Svevo samples compared with Svevo, whereas the puroindolines appeared to have little effect on L ). However, Soft Svevo and Soft Alzada differed markedly for W and L . Soft durum samples produced bread loaf volumes between the soft and hard common wheat samples but larger sugar‐snap cookie diameters than all comparison samples. The soft durum varieties exhibited new and unique flour and baking attributes as well as retaining the color and protein characteristics of their durum parents.  相似文献   

14.
In the last few years, the renewed interest for emmer wheat (Triticum dicoccon Schrank) in Italy has stimulated breeding programs for this crop releasing improved genotypes obtained not only by selection from landraces, but even by crosses with durum wheat (Triticum durum Desf.) varieties. The purpose of this work has been to uncover the genetic make-up of some emmer × durum derivatives, specifically by comparing the differences from their parents. Genetic diversity of advanced breeding lines and varieties derived from a durum × emmer cross has been evaluated on the basis of AFLP and SSR markers in comparison with the corresponding emmer and durum wheat parent for addressing the seminal question of how much ‘wild’ variation remains after selection for agronomic type.  相似文献   

15.
《Cereal Chemistry》2017,94(5):801-804
Durum breeding programs need to identify raw material traits capable of predicting whole wheat spaghetti quality. Nineteen durum wheat (Triticum turgidum L. var. durum ) cultivars and 17 breeding lines were collected from 19 different environments in North Dakota and were evaluated for physical and cooking qualities of whole wheat spaghetti. Raw material traits evaluated included grain, semolina, and whole wheat flour characteristics. Similar to traditional spaghetti, grain protein content had a significant positive correlation with cooking quality of whole wheat spaghetti. Stepwise multiple regressions showed grain protein content, mixogram break time, and wet gluten were the predominant characteristics in predicting cooked firmness of whole wheat spaghetti.  相似文献   

16.
The tetraploid relatives (subspecies) of commercial durum wheat (Triticum turgidum L. subsp. turgidum conv. durum (Desf.) MacKey) offer a source of economically useful genes for the genetic improvement of durum cultivars. Tetraploid wheat subspecies show a wide diversity in grain protein composition and content, which are major factors determining the pasta-making quality of durum cultivars. In this study, the specific focus was the identification of accessions expressing one or more superior pasta-making traits. In all, 33 accessions were surveyed representing five different subspecies; var. durum (13 accessions), polonicum (7 accessions), persicum (3 accessions), turanicum (6 accessions), and turgidum (4 accessions). These accessions and the durum cultivars Wollaroi and Kamilaroi (in both years) and Yallaroi (in 1998 only) were grown at Tamworth, Australia in 1997 and 1998. Grain, semolina, and spaghetti cooking quality were evaluated using a range of tests. Several accessions were identified with larger grain size and protein content and higher semolina extraction. Although many of the accessions were weaker in dough strength, a few were equal to the commercial cultivars and produced pasta of comparable quality. The main disadvantage with these accessions was the low yellow color. These quality defects can be corrected by conventional breeding.  相似文献   

17.
Carbon isotope discrimination (Δ) has been proposed as physiological criterion to select C3 crops for yield and water use efficiency. The relationships between carbon isotope discrimination (Δ), water use efficiency for grain and biomass production (WUEG and WUEB, respectively) and plant and leaf traits were examined in 20 Iranian wheat genotypes including einkorn wheat (Triticum monococcum L. subsp. monococcum) accessions, durum wheat (T. turgidum L. subsp. durum (Desf.) Husn.) landraces and bread wheat (T. aestivum L. subsp. aestivum) landraces and improved cultivars, grown in pots under well-watered conditions. Carbon isotope discrimination was higher in diploid than in hexaploid and tetraploid wheats and was negatively associated with grain yield across species as well as within bread wheat. It was also positively correlated to stomatal frequency. The highest WUEG and grain yield were noted in bread wheat and the lowest in einkorn wheat. Einkorn and bread wheat had higher WUEB and biomass than durum wheat. WUEG and WUEB were significantly negatively associated to Δ across species as well as within bread and durum wheat. The variation for WUEG was mainly driven by the variation for harvest index across species and by the variation for Δ within species. The quantity of water extracted by the crop, that was closely correlated to root mass, poorly influenced WUEG. Environmental conditions and genetic variation for water use efficiency related traits appear to highly determine the relationships between WUEG and its different components (water consumed, transpiration efficiency and carbon partitioning).  相似文献   

18.
The tetraploid relatives (subspecies) of commercial durum wheat (Triticum turgidum L. subsp. turgidum conv. durum (Desf.) MacKey) offer a source of economically useful genes for the genetic improvement of durum cultivars. Thirty‐two accessions, representing five different subspecies: var. durum (13 accessions), polonicum (7), persicum (3), turanicum (5), and turgidum (4) were grown at Tamworth, Australia, in 1997 and 1999. These accessions were compared with three durum cultivars: Wollaroi and Kamilaroi (in both years) and Yallaroi (in 1998 only). In this study, the glutenin subunit composition and molecular weight distribution, together with starch properties of these accessions, were studied. A much wider range in both the glutenin subunit composition and the starch RVA paste viscosities and gelatinization profiles were found in the accessions compared with the cultivated durum wheats. Most of the accessions had lower gluten strength and the presence of poor quality LMW alleles, and low proportions of unextractable polymeric protein could explain this. For starch, RVA peak viscosity correlated strongly with cooking loss of pasta, the only significant correlation between starch properties and measured aspects of pasta quality.  相似文献   

19.
Phenolic acid intake through the consumption of whole-wheat foods provides important health benefits associated with reduced risks of cardiovascular diseases and colon cancer. The genetic variation for phenolic acids was extensively studied in common wheat, but a comprehensive survey in tetraploid wheat is lacking. In this study we evaluated the genetic variability for individual and total phenolic acids concentration existing in a large collection of tetraploid wheat (Triticum turgidum L.). A 2-year evaluation was undertaken on the whole-meal flour of 111 genotypes belonging to seven T. turgidum subspecies including cultivars, landraces and wild accessions. Durum cultivars [T. turgidum subsp. durum (Desf.) MacKey], had the highest average concentration of total phenolic acids (828.7 μg g?1 dm in 2012; 834.5 μg g?1 dm in 2013) with amounts varying from 550.9 μg g?1 dm to 1701.2 μg g?1 dm, indicating a variation of greater than threefold fold. The lowest concentration of phenolic acids was found in T. turgidum subsp. dicoccum (Schrank ex Schübler) Thell. Rivet wheat (T. turgidum L. subsp. turgidum) had phenolic acid concentrations similar to those in durum, but less variation was noted among the accessions. On the other hand, the accessions of the four remaining subspecies showed lower phenolic acid concentrations and variation among the accessions as compared to durum. A total of six phenolic acids were identified across the wheat genotypes. The effects of genotype, year and year × genotype were estimated by ANOVA and resulted significant for all phenolic acids. The ratio of genotypic variance to total variance suggested the possibility of improving phenolic acid content in elite wheat germplasm through appropriate breeding programs. Moreover, significant correlations between phenolic acids and other quality characteristics of the grain were detected.  相似文献   

20.
Summary During the winters of 1990/91 and 1991/92, 181 accessions of Triticum dicoccon Schrank from the CIMMYT gene-bank were screened in the field for resistance to Russian wheat aphid, Diuraphis noxia (Kurdjumov). Accessions were sown in hill plots of 10 seeds and artificially infested with D. noxia at the two-leaf growth stage. Hills were visually assessed for damage at tillering, booting and heading. Entries differed significantly in their reaction to D. noxia, and severity of symptoms increased with time. Twenty four of the entries were highly resistant to the aphid. In winter 1991/92, 807 accessions of wild and cultivated wheats (26 species) and synthetic hexaploids were screened similarly for resistance to D. noxia. A large number of A-genome species were resistant, while few D-genome species were identified as resistant. These newly discovered sources of resistance can be used to expand the genetic base of resistance to D. noxia in both bread (T. aestivum L.) and durum wheats (T. turgidum L. convar. durum (Desf.) Mackey).  相似文献   

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