Production of aneuhaploid and euhaploid sporocytes by meiotic restitution in fertile hybrids between durum wheat Langdon chromosome substitution lines and Aegilops tauschii

Fertile F1 hybrids were obtained between durum wheat （Triticum durum Desf.） Langdon （LDN） and its 10 disomic substitution （LDN DS） lines with Aegilops tauschii accession AS60 without embryo rescue. Selfed seedset rates for hybrids of LDN with AS60 were 36.87% and 49.45% in 2005 and 2006, respectively. Similar or higher selfed seedset rates were observed in the hybrids of 1D （1A）, 1D （1B）, 3D （3A）, 4D （4B）, 7D （7A）, and 2D （2B） with AS60, while lower in hybrids of 3D （3B） ＋ 3BL, 5D （5A） ＋ 5AL, 5D （5B） ＋ 5B and 6D （6B） ＋ 6BS with AS60 compared with the hybrids of LDN with AS60. Observation of male gametogenesis showed that meiotic restitution, both first-division restitution （FDR） and single-division meiosis （SDM） resulted in the formation of functional unreduced gametes, which in turn produced seeds. Both euhaploid and aneuhaploid gametes were produced in F1 hybrids. This suggested a strategy to simultaneously transfer and locate major genes from the ancestral species T. turgidum or Ae. tauschii. Moreover, there was no significant difference in the aneuhaploid rates between the F1 hybrids of LDN and LDN DS lines with AS60, suggesting that meiotic pairing between the two D chromosomes in the hybrids of LDN DS lines with AS60 did not promote the formation of aneuhaploid gametes.

Isolation and Analysis of α-Gliadin Gene Coding Sequences from Triticum durum

Three coding sequences of gliadins genes, designed as Gli2_Dul, Gli2_Du2 and Gli2_Du3, were isolated from the genomic DNA of Triticum durum accessions CItr5083. Gli2_Dul and Gli2_Du2 contain 945 and 864 bp, encoding the mature proteins with 314 and 287 amino acid residues, respectively. Gli2_Du3 is recognized as a pseudogene due to the stop codon occurring in the coding region. The pseudogenes, commonly occurring in gliadins family, are attributed to the single base change C→T. The amino acid sequences deduced from these gene sequences were characterized with the typical structure of α-gliadin proteins, including the toxic sequences （PSQQQP）. The peptide fraction PF（Y）PP（Q）is thought to be an extra unit of repetitive domain, slightly diverging from the previous report. Six cysteine residues were observed within two unique domains. Phylogenetic analysis showed Gli2_Du2 and Gli2_Du3 were closely related to the genes on chromosome 6A, whereas Gli2_Dul seems to be more homologous with the genes on chromosome 6B.

Mapping of dwarfing gene Rht14 in durum wheat and its effect on seedling vigor, internode length and plant height

Short coleoptiles associated with GA-insensitive Rht-1 alleles in wheat reduces yield due to poor seedling establishment under dry, or stubble-retained conditions. Hence there is a need for alternative dwarfing genes for wheat improvement programs. GA-sensitive dwarfing gene Rht14 confers semidwarf stature in wheat while retaining longer coleoptiles and early seedling vigor. Two RIL populations were used to identify the map position of Rht14 and to estimate its effect on plant height, coleoptile length, seedling shoot length,spike length and internode length. Rht14 on chromosome 6 A was mapped in the genomic region 383–422 Mbp flanked by GA2oxA9 and wmc753 in a Bijaga Yellow/Castelporziano RIL population. Recombination events between Rht14 and GA2oxA9 in the RIL population indicated that Rht14 might not be allelic to GA2oxA9. The conserved DNA sequence of GA2oxA9 and its flanking region in Castelporziano also suggested that the point of mutation responsible for the Rht14 allele must be a few Mbp away from GA2oxA9. The dwarfing effects of Rht14 on plant height, internode length and seedling vigor were compared with those of Rht-B1 b in an HI 8498/Castelporziano RIL population. Both genes significantly reduced plant height and internode length. Rht-B1 b conferred a significant reduction in coleoptile length and seedling shoot length, whereas Rht14 reduced plant height, but not coleoptile and seedling shoot length. Therefore, Rht14 can be a used as an alternative to Rht-B1 b for development of cultivars suitable for deeper sowing in dry environments and in conditions of conservation agriculture where crop residues are retained.

Interpreting genotype × environment interactions for grain yield of rainfed durum wheat in Iran

Clustering genotype × environment(GE) interactions and understanding the causes of GE interactions are among the most important tasks in crop breeding programs. Pattern analysis(cluster and ordination techniques) was applied to analyze GE interactions for grain yield of 24 durum wheat(Triticum turgidum L. var. durum) genotypes(breeding lines and old and new cultivars) along with a popular bread wheat(Triticum aestivum) cultivar grown in 21 different rainfed environments during the 2010–2013 cropping seasons. To investigate the causes of GE interaction, several genotypic and environmental covariables were used. In a combined ANOVA, environment was the predominant source of variation,accounting for 81.2% of the total sum of squares(TSS), and the remaining TSS due to the GE interaction effect was almost seven times that of the genetic effect. Cluster analysis separated the environments into four groups with similar discriminating ability among genotypes, and genotypes into five groups with similar patterns in yield performance.Pattern analysis confirmed two major environmental clusters(cold and warm), and allowed the discrimination and characterization of genotype adaptation. Within the cold-environment cluster, several subclusters were identified. The breeding lines were most adapted to moderate and warm environments, whereas the old varieties were adapted to cold environments. The results indicated that winter rainfall and plant height were among the environmental and genotypic covariables, respectively, that contributed most to GE interaction for grain yield in rainfed durum wheat.

Planting Date, Seeding Rate, and Cultivar Impact Agronomic Traits and Semolina of Durum Wheat

Durum wheat (Triticum durum Desf.) is a market class of wheat subject to price discounts in the marketplace if quality standards are not met. This study was conducted in order to determine how certain agronomic practices might impact durum wheat quality. The effects of planting date (PD), cultivar, and seeding rate on agronomic and semolina quality traits were investigated in field trials conducted near Hettinger and Minot, ND in 2014 and 2015. The interaction of PD and cultivar was significant for many of the traits evaluated. There was a significant PD X cultivar interaction or PD and cultivar effect for yield in all environments. Planting date X cultivar interacted for test weight at all environments. In general, a delay in PD resulted in a significant decrease in yield and test weight for all cultivars. However, Carpio yielded more than other cultivars in high yielding environments while the yield and test weight of Joppa was more adversely affected by delays in PD. Seeding rate did not have a consistent effect on any agronomic or quality trait. Protein content, kernel yellow pigment content, falling number (FN), and vitreous kernels were more dependent on cultivar, regardless of PD and environment. Semolina extraction, gluten index (GI), and wet gluten (WG) values tended to decrease with a delay in PD. These data continue to support cultivar selection as a critical component for obtaining high-yielding, high-quality durum wheat. However, PD and environment can impact certain agronomic and end-use traits, regardless of cultivar grown.

Grain yield losses in yellow-rusted durum wheat estimated using digital and conventional parameters under field conditions

The biotrophic fungus Puccinia striiformis f. sp. tritici is the causal agent of the yellow rust in wheat. Between the years 2010–2013 a new strain of this pathogen(Warrior/Ambition),against which the present cultivated wheat varieties have no resistance, appeared and spread rapidly. It threatens cereal production in most of Europe. The search for sources of resistance to this strain is proposed as the most efficient and safe solution to ensure high grain production. This will be helped by the development of high performance and low cost techniques for field phenotyping. In this study we analyzed vegetation indices in the Red,Green, Blue(RGB) images of crop canopies under field conditions. We evaluated their accuracy in predicting grain yield and assessing disease severity in comparison to other field measurements including the Normalized Difference Vegetation Index(NDVI), leaf chlorophyll content, stomatal conductance, and canopy temperature. We also discuss yield components and agronomic parameters in relation to grain yield and disease severity.RGB-based indices proved to be accurate predictors of grain yield and grain yield losses associated with yellow rust(R2= 0.581 and R2= 0.536, respectively), far surpassing the predictive ability of NDVI(R2= 0.118 and R2= 0.128, respectively). In comparison to potential yield, we found the presence of disease to be correlated with reductions in the number of grains per spike, grains per square meter, kernel weight and harvest index. Grain yield losses in the presence of yellow rust were also greater in later heading varieties. The combination of RGB-based indices and days to heading together explained 70.9% of the variability in grain yield and 62.7% of the yield losses.

Sensitivity of durum wheat (Triticum turgidum) to various postemergence herbicides

There are a limited number of herbicide options available for durum wheat production in Ontario, Canada. Four field studies were conducted in Ontario, Canada over a three year period (2008, 2009 and 2010) to evaluate the sensitivity of spring planted durum wheat to post-emergence (POST) applications of dichlorprop/2,4-D, dicamba/ MCPA/mecoprop, clopyralid, bromoxynil/MCPA, pyrasulfotole/bromoxynil, thifensulfuron/tribenuron + MCPA amine, fluroxypyr + MCPA ester, tralkoxydim and fenoxaprop-p-ethyl/safener at the manufacturers’ recommended dose and twice that dose. Visible injury in durum wheat were 0 to 2.4% with dichlorprop/2,4-D, 0 to 6% with dicamba/MCPA/mecoprop, 0 to 0.4% injury with clopyralid, 0 to 1.4% injury with bromoxynil/MCPA, 0 to 3.5% with pyrasulfotole/bromoxynil, 0 to 5% with thifensulfuron/tribenuron + MCPA amine, 0 to 2.6% with fluroxypyr + MCPA ester, 0 to 5% with tralkoxydim and 0.4% to 8% with fenoxaprop-pethyl/safener at various evaluation dates (1, 2, 3 and 4 weeks after treatment). Durum wheat height was decreased as much as 5% with dicamba/ MCPA/mecoprop, 4% with pyrasulfotole/bromoxynil and 6% with fenoxaprop-pethyl/safener but was not affected with other herbicides evaluated. There was no decrease in durum wheat yield with the herbicides evaluated.

Field evaluation of durum wheat landraces for prevailing abiotic and biotic stresses in highland rainfed regions of Iran

Biotic and abiotic stresses are major limiting factors for high crop productivity worldwide. A landrace collection consisting of 380 durum wheat(Triticum turgidum L. var. durum) entries originating in several countries along with four check varieties were evaluated for biotic stresses:yellow rust(Puccinia striiformis Westendorf f. sp. tritici) and wheat stem sawfly(WSS) Cephus cinctus Norton(Hymenoptera: Cephidae), and abiotic stresses: cold and drought. The main objectives were to(i) quantify phenotypic diversity and identify variation in the durum wheat landraces for the different stresses and(ii) characterize the agronomic profiles of landraces in reaction to the stresses. Significant changes in reactions of landraces to stresses were observed.Landraces resistant to each stress were identified and agronomically characterized.Percentage reduction due to the stresses varied from 11.4%(yellow rust) to 21.6%(cold stress) for 1000-kernel weight(TKW) and from 19.9(yellow rust) to 91.9%(cold stress) for grain yield. Landraces from Asia and Europe showed enhanced genetic potential for both grain yield and cold tolerance under highland rainfed conditions of Iran. The findings showed that TKW and yield productivity could be used to assess the response of durum wheat landraces to different stresses. In conclusion, landraces showed high levels of resistance to both biotic and abiotic stresses, and selected landraces can serve in durum wheat breeding for adaptation to cold and drought-prone environments.

Using Bayesian and Eigen approaches to study spatial genetic structure of Moroccan and Syrian durum wheat landraces

The Mediterranean durum wheat landraces are genetically diverse and important sources for improving resistance to abiotic and biotic stresses and developing adapted and productive durum wheat varieties in the Mediterranean region. To study the diversity two distant countries (MoroccoandSyria) durum landraces were studied. Fifty-one microsatellites were used as molecular markers tool to determine the genetic structure and spatial adaptation of these landraces. We used two spatially-explicit methods (Bayesian and Eigen) to determine the genetic diversity and structure of a population composed of Moroccan (98) and Syrian (90) durum wheat landraces. Non-spatial methods were also applied for comparison. A significant genetic difference was detected between the landraces originated from Morocco and Syria. Six subpopulations were revealed for each country using the Bayesian method and the Eigenanalysis, which generated PC1 and sPC1, showed similar structure. Eigenanalysis exhibited a significant global genetic structure for both countries landraces;and showed that neighboring landraces tend to have close genetic profile. The two first axes of PC1 and sPC1 had discriminated four out of the six subpopulations revealed by the Bayesian methodology. Also, our study detected the close relationship between the durum landraces from the coastal areas of Syria and the Moroccan landraces from the Atlantic coastal regions where the Phoenicians/Carthaginians had settled in Morocco. These results demonstrate the importance of using the spatial models in genetic analysis of durum wheat landraces;and also recommend the use of the easily usable Eigenanalysis to analyze the genetic diversity and structure.

Composition and Molecular Weight Distribution of Albumin and Globulin Protein Isolates from Durum Wheat Genotypes

This paper attempts to evaluate the banding patterns of non-gluten protein isolates from the grain of durum wheat varieties. Under reduced condition, polyacrylamide-gel electrophoresis has revealed a number of different sized albumin and globulin protein bands. The electrophoretic pattern of globulin showed more polymorphisms than that of albumin. High polymorphism, both in band intensity and occurrence, was observed between 15 kDa and 35 kDa. Most of the protein bands were scored in the range of 10 kDa and 85 kDa in the two protein fractions. At a cutoff point 2.5, cluster analysis based on the SDS-PAGE of globulin proteins classified the durum wheat varieties into three major family groups. Generally, the experiment showed the suitability and usefulness of globulin protein fractions as a genetic marker in discriminating durum wheat genotypes.

Morphological and Physiological Traits of Assistance in the Selection of High Yielding Varieties of Durum Wheat (<i>Triticum turgidum</i>L. spp. Durum) for the Rainfed Mediterranean Environments of Central Chile

Chile has high potential to produce quality durum wheat;however, it is not self-sufficient. It is necessary to increase durum grain yield in the Mediterranean rainfed areas which are characterized by adverse environmental conditions, mainly, water deficit. The criteria normally used by breeders to select varieties of wheat for these environments are yield under stress and early flowering. The objective of this monograph is to propose that the selection of high yielding genotypes of durum wheat, under Chilean Mediterranean rainfed conditions, be assisted by morphological and physiological traits associated with yield in order to increase its heritability.

Selection of Tolerant Lines to Salinity Derived from Durum Wheat (<i>Triticum durum</i>Desf.) in Vitro Culture

The genetic variability is considered as the major principle of plant breeding for durum wheat. This variability can be induced in vitro by selection pressure exerted by stress factors such as salinity in order to regenerate the vitro plantlets tolerant. This study aims in the first step in the regeneration of plantlets tolerant to salinity from mature embryos culture derived from two Tunisian durum wheat varieties: improved (Razzek) and landrace (Jenah Khotifa (JK)) varieties. The tolerance evaluation to salt stress was applied in vitro (100 mmol&middotl-1 NaCl) and was based on various parameters. Our results showed that JK variety was distinguished by a stable response for all parameters tested: average weight of callus (368.1 mg for control and 307 mg under salt stress), callus regenerated percentage (36.6% for control and 35.7% under salt stress) and green shoots number/callus (17 for control and 17 under salt stress). This stability of response translates the adaptability of this variety to salinity. In order to fix regenerated JK plantlets in single generation and obtain HDs homozygous stable lines, in vitro gynogenesis technical is tested for this genotype. The Evaluation of gynogenetic capacity focused on about 1200 unfertilized ovaries of JK and was based on its ability to induction, differentiation, development of green shoots, and haploid plantlets regeneration. JK showed good tolerance to salinity and a relatively good response to gynogenesis.

Hungaro Durum Rye—Breeding, Genome Composition and Amino Acid Content of the First Triticale Cultivar for Human Consumption

Hungaro triticale cultivar was bred for human consumption and animal fodder in Kisvárda, Hungary. The breeding method applied for the recombinant secondary hexaploid triticale proved to be effective since the favourable traits of wheat, durum wheat and rye were successfully combined in the genome of the new cultivar. The first aim was to characterize the genome composition. Multicolour genomic in situ hybridization (mcGISH) was used for the genome compositional analysis. According to the results, the cultivar contains the wheat AB genome (AABB = 28 chromosomes) and the whole rye (R) genome (RR = 14 chromosomes). The presence of D genome, however, could not be detected within the detection limit of the GISH method. Hungaro is the very first triticale in Hungary that has been used for human consumption (milling industry, baking industry, pasta production). In this study, amino acid content of flours was measured. Amino acid investigations on Hungaro durum rye’s flour showed that the quantity of essential amino acids, especially of methionine and cysteine, are higher in Hungaro durum rye than in the also investigated Ryefood rye cultivar and the GK ?thalom wheat cultivar. The genes inherited from the wheat species ensure high yield and great baking and dough making qualities. Therefore, its flour is suitable in itself for pastry and dough production (without mixing it with other flours). Its characteristics inherited from rye guarantee excellent abiotic and biotic resistance.

Effect of Lead Toxicity on Germination and Enzymatic Activity of Durum Wheat Triticum durum Desf.

The aim of this work is to identify the effect of lead on germinal parameters and the antioxidant enzyme activities （lipase, peroxidase and catalase） in durum wheat Triticum durum Desf. cv （waha, vitron and gta） exposed to the concentrations of 0, 0.15, 0.25 and 0.3 g/L of Pb （NO3）2 during germination process. The obtained results showed that lead reduced the germination, root and aerial biomass. The concentration of 0.3 g/L inhibited completely the germination of the three varieties. It also slowed lipase activity, the degradation of lipids of the seed＇s reserves and disrupted the metabolism of peroxidase and catalase. Concerning the behavior of the three varieties studied, it appears that the Vitron is the best predisposed variety to stand against lead stress by its strong antioxidant defense system.

Effect of Weather on Grain Quality Traits of Durum Wheat Grown in the Northern Plains of USA

The objective of this research was to determine the effect of genotype and growing environment, particularly weather, on grain quality traits of durum wheat using nine genotypes (Alkabo, Carpio, Divide, Grenora, Joppa, Maier, Mountrail, Pierce, and Tioga) grown in four years (2012-2015) at six locations in North Dakota, USA. The results of this research indicated that grain test weight, 1000-kernel weight, protein content, kernel vitreousness, and falling number were affected more by environment than by genotype. However, genotypes within an environment differed in the magnitude of their response and this difference could be used to select genotypes in a breeding program to improve quality. For a given quality trait, the magnitude of the response reflects the stability of the trait to changes in the environment. In general, the quality of durum wheat grown in the northern plains of USA was favored by warm daytime temperature, low night temperature, and low relative humidity. Growing locations with high maximum air temperature and a high number of days with temperature ≥ 30°C had a positive effect on grain protein content and falling number, while a high number of days with night time temperature ≤ 13°C were ideal for 1000-kernel weight. Low rainfall and low relative humidity promoted a high falling number and vitreous kernel content. The results of this study suggested that genotypes could be selected based on their overall quality and their stability across environments. Trait stability could be an important consideration when growers select genotypes for planting in their fields.

GGE Biplot Analyses for Grain Quality and Yield of Durum Wheat (Triticum turgidum ssp. durum Desf.) Landraces Populations

The aim of this study was to determine the GY (grain yield) and some quality characters of durum wheat landraces under Thrace Region ecological conditions. This study was carried out in randomized complete blocks design with three replications in the locations of Tekirdag, Edirne, Klrklareli and Lüleburgaz during the growing years of 2009 and 2010. In the research, 20 durum wheat landraces obtained from different regions of Turkey and 5 obsolete durum wheat cultivars were used as the experimental material. It was determined that the GY, TW (test weight) and PC (protein content) in the first year were higher than the second year in this study. The highest values for GY, TGW (thousand grain weight), and TW and GVR (grain vitreousness rate) were determined in Tekirdag location, while the highest PC was determined in Edirne location. The results of the research showed that GY varied between 321.17-470.33 kg da^-1 in Tekirdag, 301.33-404.00 kg da^-1 in Edirne;197.50-334.67 kg da^-1 in K?rklareli and 280.00-501.33 kg da^-1 in Lüleburgaz. TGWs were determined between 38.17-44.50 g of Tekirdag, 36.00-43.00 g of Edirne, 38.43-43.67 g of Karklareli and 35.33-45.67 g of Lüleburgaz. TW of Tekirdag, Edirne, Karklareli and Lüleburgaz locations changed between 74.67-79.33 kg hl^-1, 69.33-76.83 kg hl^-1, 70.00-75.17 kg hl^-1 and 71.00-77.50 kg hl^-1, respectively. The GVR was determined among 85.00-96.83% in Tekirdag, 68.33-93.33% in Edirne, 67.83-93.83% in Klrklareli, and 85.17-98.17% in Lüleburgaz. The PC of grains was measured among 13.32-14.95% in Tekirdag, 14.90-16.25% in Edirne, 14.27-16.17% in K?rklareli, and 13.40-16.53% in Lüleburgaz. It was determined that Dicle and Dicle-13 landraces for GY and TW, Adlyaman landrace for TGW,Canakkale and Akbugday landraces for the GVR, and Iskenderun, Akbu?day, Erzincan landraces for PC have the highest values.

The Effect of Zinc （Zn） Fertilization on Alleviating Cd Accumulation in Durum Wheat Grain

Cadmium （Cd） contamination of agricultural soils may pose severe risks and hazards for humans through food chain, as crop plants accumulate Cd in their edible tissues. Cd translocation from soil to plant is largely dependent on soil and plant type. Cd accumulation occurs much more in crop plants grown in soils with severe zinc （Zn） deficiency and durum wheat tends to accumulate more Cd in grain than the other cereals. The objective of this study was to evaluate the alleviating effect of Zn fertilization on Cd accumulation in durum wheat grain. A pot experiment including foliar Zn application of 0.3% w/v ZnSO4 and soil Cd applications of 0, 0.2 and 1.0 mg/kg was carried out in a completely randomized design using a Zn-deficient soil. Grain Cd concentration of plants receiving 0 mg/kg Cd was 31 μg/kg, whereas with 0.2 mg/kg and 1.0 mg/kg Cd applications it increased to the levels of 215 μg/kg and 1,489 μg/kg, respectively. Along with 0.3% ZnSO4 leaf applications, grain Cd concentrations decreased to 171 μg/kg and 754 μg/kg, by a reduction of 20.5% and 49.3%, respectively. In conclusion, it was determined that leaf applied Zn fertilizer might alleviate Cd accumulation in durum wheat grain in Zn deficiency conditions.

Characterization of New Allelic Variation for Glutenin in EMS-Mutant Durum Wheat Population （Triticum turgidum L. subsp, durum （Desf.））

The High Molecular Weight HMW-GS and Low-Molecular-Weight LMW-GS Glutenin Subunits are major determinants of wheat dough processing qualities. Tilling populations was generated by EMS mutagenesis from Chaml durum variety. Protein quality was investigated by SDS sedimentation, protein content, gluten content and thousand kernel weights. 21 mutants were selected from 1,500 lines of tilling population depending on the variations of their electrophoresis profiles. The analysis of Glu-B 1 HMW-GS has showed two types of profiles： lines deficient on Bx7 and lines with expression of new protein between （Bx7-ByS） allelic pair combination. The majority of these mutant lines have showed quality compounds associated with bad technological characteristics like the parent Cham l with the exception of two mutant lines expressing new protein that have significantly stronger gluten properties an one mutant deficient on Bx7 HMW-GS that developed high value of SDS. For Glu-B3 LMW-GS coding for LMW glutenin type 1 and 2, new mutant line showing expression of new protein pattern. The mutant showing over-expression of bands on gel SDS-PAGE for LMW typel like Chaml, have produced the highest protein and gluten content, while the new mutant showing new profile have showed high value of Gluten and SDS.

The Effect of Weather and Agronomic Practice on Deoxynivalenol Mycotoxin in Durum Wheat

Deoxynivalenol （DON） produced by Fusarium graminearum and F. culmorum in durum wheat （Triticum turgidum L. var. durum） is an important food safety issue for the cereal chain. A number of agronomic practices are known to affect the infection and mycotoxin production by these Fusarium species in cereal grains. A field study was conducted to compare the natural occurrence of DON in durum wheat grown under conventional （n = 67 samples） and organic （n = 50） farming conditions during two consecutive crop years. DON mean levels were 95 and 194 μg/kg in conventional and organic durum wheat, respectively. The incidence and levels of DON were higher in the second crop year due to higher rainfall （〉 100 mm） during flowering. Overall, organically managed farming system may provide Lsome reduction in DON levels in durum wheat, which could be attributable to the lower intensity of cultivation in addition to the different system of cropping rotation. However, favourable weather conditions are likely to be more important for DON contamination than crop system.