Durum Wheat Breeding Lines Research Articles

Recurrent selection for Fusarium head blight resistance in a durum wheat population

AbstractFusarium head blight (FHB) is a devastating fungal disease of wheat. Since early 1990s, frequent FHB epidemics in major wheat‐growing regions have caused massive economic losses. Developing FHB‐resistant varieties is key to minimize the loss caused by the disease. In durum wheat (Triticum turgidum L. ssp. durum), however, it is challenged by lack of resistant sources. Introgression of resistance genes from wild relatives and bread wheat has resulted in some durum wheat lines with moderate resistance. Due to its complex genetic nature, integrating more resistance genes with moderate and even minor effects promises to provide high and durable FHB resistance. In this study, a base population was developed using diverse resistant lines and elite durum wheat breeding lines as founders and went through three cycles of phenotypic selection from 2019 to 2022, with FHB severity decreased by 34%. Six S0:1 lines in Cycle 2 and Cycle 3 populations exhibited significantly lower FHB severity than the moderately susceptible check variety ND Riveland. The results suggested that recurrent phenotypic selection could effectively improve FHB resistance. Analysis of the founders and Cycle 2 and Cycle 3 populations with 2706 single nucleotide polymorphism markers indicated that there was little decrease in genetic variation due to selection. Genome‐wide association analysis found no markers significantly associated with FHB severity. Genomic prediction accuracies based on cross‐validation for FHB severity, plant height, and days‐to‐flowering were 0.51, 0.69, and 0.61, respectively. Recurrent genomic selection can shorten the select cycle to 4 months and therefore is promising to accelerate genetic improvement of FHB severity.

Assessment of flag leaf water status as drought tolerance discriminating trait in durum wheat (Triticum turgidum var durum L.)

Drought is a prominent limiting factor that impacts negatively durum wheat grain yield. Ten durum wheat breeding lines were evaluated under rainfall conditions at the Field Crop Institute Agricultural Experimental Station of Setif, Algeria, during the 2016/2017 cropping season. The investigation aimed to study the ability of flag leaf water status to discriminate among varieties for drought tolerance trait. Significant variability was observed among the tested varieties for leaf dry, wilted and turgid weights, leaf relative water content, water saturation deficit and excised water loss, after three wilting periods of 30, 60 and 90 minutes dehydration at 40°C. The assessed breeding lines were differentially categorized as drought tolerant and drought sensitive based on either relative water content or water saturation deficit or excised leaf water loss genotypic mean values. Correlation, principal components and cluster analyses indicated an unwanted significant association between excised leaf water loss and relative water content and water saturation deficit and classified the assessed entries into three clusters (CI, C2 and C3). Cluster C1 had high relative water content, low water saturation deficit but high excised water loss, while C3 had low relative water content, low excised leaf water but high-water saturation deficit, C2 being intermediate. Crosses between distant clusters (C1 vs C3) are proposed to generate more variability of the targeted traits in progeny population and to break undesirable linkage between alleles controlling leaf water status, allowing to select efficiently drought tolerant genotypes.

Genome-Wide Association Studies Reveal All-Stage Rust Resistance Loci in Elite Durum Wheat Genotypes.

Leaf rust, caused by Puccinia triticina (Pt), stripe rust caused by Puccinia striiformis f. sp. tritici (Pst), and stem rust caused by Puccinia graminis f. sp. tritici (Pgt) are major diseases to wheat production globally. Host resistance is the most suitable approach to manage these fungal pathogens. We investigated the phenotypic and genotypic structure of resistance to leaf rust, stem rust, and stripe rust pathogen races at the seedling stage in a collection of advanced durum wheat breeding lines and cultivars adapted to Upper Mid-West region of the United States. Phenotypic evaluation showed that the majority of the durum wheat genotypes were susceptible to Pt isolates adapted to durum wheat, whereas all the genotypes were resistant to common wheat type-Pt isolate. The majority of genotypes were resistant to stripe rust and stem rust pathogen races. The durum panel genotyped using Illumina iSelect 90 K wheat SNP assay was used for genome-wide association mapping (GWAS). The GWAS revealed 64 marker-trait associations (MTAs) representing six leaf rust resistance loci located on chromosome arms 2AS, 2AL, 5BS, 6AL, and 6BL. Two of these loci were identified at the positions of Lr52 and Lr64 genes, whereas the remaining loci are most likely novel. A total of 46 MTAs corresponding to four loci located on chromosome arms 1BS, 5BL, and 7BL were associated with stripe rust response. None of these loci correspond to designated stripe rust resistance genes. For stem rust, a total of 260 MTAs, representing 22 loci were identified on chromosome arms 1BL, 2BL, 3AL, 3BL, 4AL, 5AL, 5BL, 6AS, 6AL, 6BL, and 7BL. Four of these loci were located at the positions of known genes/alleles (Sr7b, Sr8155B1, Sr13a, and Sr13b). The discovery of known and novel rust resistance genes and their linked SNPs will help diversify rust resistance in durum wheat.

Genetic Distance of New Bulgarian Durum Wheat Varieties and Breeding Lines of FCI-Chirpan, Bulgaria

The durum wheat breeding program in Field crops institute FCI - Chirpan started in 1928. In the last ten years, a number of varieties have been created to meet modern cultural requirements. Genetic distance is of great importance for the success of the combining breeding. In the study are included 13 varieties created over the last 10 years and 8 of the Institute's best advanced durum wheat breeding lines. The field experiment was conducted in experimental field of FCI-Chirpan during 2015-2017 year. A randomized block design in four replicated was used with a trial plot size of 15 m2. A standard farming technology for durum wheat in the country was applied. Tre traits: grain yield, plant height, heading date, test weight, 1000 kernel weight, protein content, wet gluten and vitreousness were observed. The means of three-year trials for all studied traits were calculated and genetic differences between genotypes were found. The coefficients of variation (CV%) obtained for the individual traits show that the heading date and grain yields are the most variable. The correlation analysis determines significant coeficients for 9 out of 28 possible combinations of traits. The multivariate methods for determining the genetic distance between the involved genotypes in the study were used. According to the dendrogram of the cluster analysis, the distances between the four main groups formed are determined. The applied graphical PC analysis shows the interrelations between the traits and the grouping of genotypes in terms of the genetic distance between them. These methods can help for faster breeding progress using the established genetic distance as the basis for deploying the breeding program.

Correction: Single Marker and Haplotype-Based Association Analysis of Semolina and Pasta Colour in Elite Durum Wheat Breeding Lines Using a High-Density Consensus Map.

[This corrects the article DOI: 10.1371/journal.pone.0170941.].

Phenotypic and biochemical characterization of new advanced durum wheat breeding lines from Algeria that show resistance to fusarium head blight and to mycotoxin accumulation

Durum wheat (Triticum turgidum L. var. durum) is a crop highly susceptible to Fusarium head blight (FHB), which results in yield losses and downgrades the quality of grains mostly due to mycotoxin contamination. Although breeding for resistance to FHB is one of the most promising strategy for minimizing crop damage, the attempts to obtain durum wheat resistant lines have been limited so far. Two potentially interesting lines were recently delivered by a breeding program based on crosses involving cultivars from Europe and Syria. Using a field experiment in Algeria with four different Fusarium culmorum strains and a spray inoculation method, we demonstrated that the two breeding lines were significantly less affected than a set of commercial cultivars. The two breeding lines were shown to exhibit a higher resistance to both initial fungal infection and disease spread , and to mycotoxin contamination. In addition, a detailed analysis of 2 phenolic acid composition of grains indicates significant differences in p-coumaric acid between the FHB-resistant breeding lines and the sensitive genotypes. Our results corroborate the importance of cell wall composition in preventing the diffusion of F. culmorum and therefore contributing to the resistance of cereals to FHB.

Single Marker and Haplotype-Based Association Analysis of Semolina and Pasta Colour in Elite Durum Wheat Breeding Lines Using a High-Density Consensus Map.

Association mapping is usually performed by testing the correlation between a single marker and phenotypes. However, because patterns of variation within genomes are inherited as blocks, clustering markers into haplotypes for genome-wide scans could be a worthwhile approach to improve statistical power to detect associations. The availability of high-density molecular data allows the possibility to assess the potential of both approaches to identify marker-trait associations in durum wheat. In the present study, we used single marker- and haplotype-based approaches to identify loci associated with semolina and pasta colour in durum wheat, the main objective being to evaluate the potential benefits of haplotype-based analysis for identifying quantitative trait loci. One hundred sixty-nine durum lines were genotyped using the Illumina 90K Infinium iSelect assay, and 12,234 polymorphic single nucleotide polymorphism (SNP) markers were generated and used to assess the population structure and the linkage disequilibrium (LD) patterns. A total of 8,581 SNPs previously localized to a high-density consensus map were clustered into 406 haplotype blocks based on the average LD distance of 5.3 cM. Combining multiple SNPs into haplotype blocks increased the average polymorphism information content (PIC) from 0.27 per SNP to 0.50 per haplotype. The haplotype-based analysis identified 12 loci associated with grain pigment colour traits, including the five loci identified by the single marker-based analysis. Furthermore, the haplotype-based analysis resulted in an increase of the phenotypic variance explained (50.4% on average) and the allelic effect (33.7% on average) when compared to single marker analysis. The presence of multiple allelic combinations within each haplotype locus offers potential for screening the most favorable haplotype series and may facilitate marker-assisted selection of grain pigment colour in durum wheat. These results suggest a benefit of haplotype-based analysis over single marker analysis to detect loci associated with colour traits in durum wheat.

Utilization of Mixolab for assessment of durum wheat quality dependent on climatic factors

For durum wheat quality assessment the commonly used parameters are protein content, yellow pigment content, hectoliter mass, grain vitreousness, 1000-grain weight and sodium dodecyl sulphate sedimentation. For wheat processing quality, in this study the Mixolab, instrument of a newer generation was used. Mixolab has been largely used for a rapid assessment of the Triticum aestivum quality but there is no a lot of data about durum wheat quality assesment. Therefore, the aim of this work was to test its potential in the quality characterization of fourteen durum wheat breeding lines grown during two production years with different climate conditions. The obtained results showed significant differences in starch-amylase complex part of Mixolab curve between two studied years. Mixolab parameters C3, C4 and C5 were in line with Falling Number values and amylolytic activity of samples. Samples from 2013 production year with higher precipitation sum had lower values of C3, C4 and C5 parameters as well as Falling Number values and higher amylolytic activity. On contrary, protein part of Mixolab curves expressed differences in dependence of genotype. In comparison to the standard parameters of protein and starch quality of durum wheat, Mixolab provides more complete information in a shorter time frame.

Molecular variation of improved durum wheat genotypes based on inter-simple sequence repeats fingerprinting

Durum wheat (Triticum turgidum L. var. durum) is an important crop with high protein content and superior cooking quality which used for Pasta production. In present study, the molecular diversity of eighteen durum wheat breeding lines along with one durum wheat check cultivar were evaluated based on inter simple sequence markers. Eight used primers amplified a total of 93 bands, among which 77 bands (about 83%) were polymorphic. A total of 77 polymorphic fragments were scored with average 9.6 polymorphic bands per primer. The polymorphism information content value ranged between 0.27 and 0.36 for ISSR primers. Cluster analysis using UPGMA method and Dice similarity coefficient grouped the 19 genotypes into four separated clusters. The Dice similarity coefficients revealed maximum similarity (0.91) between 20A-URDYT-10 and 20A-URDYT-11 genotypes. PCA based on molecular data distinguished genotypes similar to the cluster analysis results. The results revealed that ISSR technique is a simple, informative and suitable approach for assessment of molecular diversity in durum wheat.

Estimating grain yield losses caused by septoria leaf blotch on durum wheat in Tunisia

Septoria leaf blotch (SLB), caused by Zymoseptoria tritici (Desm.) Quaedvlieg & Crous, 2011 (teleomorph: Mycosphaerella graminicola (Fuckel) J. Schrot.), is an important wheat disease in the Mediterranean region. In Tunisia, SLB has become a major disease of durum wheat (Triticum turgidum L. subsp. durum [Desf.] Husn.) particularly during favorable growing seasons where significant yield losses and increase of fungicides use were recorded over the last three decades. The objectives of this study were to evaluate the effect of SLB severity on grain yield of new elite durum wheat breeding lines and to measure the relative effect of fungicide control on grain yield. Experiments were conducted during 2007-2008 and 2008-2009 cropping seasons. A set of 800 breeding lines were screened for reaction to SLB under natural infection at Beja research station. To estimate the disease effect, correlation between disease severity at early grain filling stage and grain yield was performed. Results showed that susceptible varieties yield was significantly reduced by SLB. Average yield reduction was as high as 384 and 325 kg ha-1 for every increment in disease severity on a 0-9 scale in both seasons, respectively. A negative correlation coefficient varied between -0.61 and -0.66 in both seasons. Treated and untreated trials conducted during 2008-2009 and 2009-2010 showed that yield of treated plots increased by 50% on the commonly cultivated susceptible varieties. The results of this investigation suggested that septoria incidence is related to large grain yield losses particularly on susceptible high yielding cultivars. However, appropriate fungicide application at booting growth stage could be beneficial for farmers. The development and use of more effective fungicide could be sought to alleviate the disease effects and therefore could be considered as a part of the integrated pest management and responsible use strategy on septoria leaf blotch in Tunisia.

Genetic gain in grain yield and drought tolerance of durum wheat breeding lines under rainfed conditions in Iran

The main objective of this study was to evaluate the genetic gain for grain yield, yield attributes and drought tolerance of 11 durum breeding lines and also to compare it with one modern cultivar and two durum and bread wheat landraces in contrasting environment groups in a period of four cropping seasons (2005–09) within the Iran/ICARDA joint project for moderately cold rainfed areas of Iran. The significant genotype × year interaction indicated that the average yield performance of genotypes across environments was not consistent over the years. Genetic gain (%) for grain yield was distinguishable between the stressed and non-stressed environments. A positive genetic gain (27.7 to 23.9%) was observed in the non-stressed environment and a negative genetic gain (−11.5 to −24.1%) in the stressed environment for the breeding lines, compared to the landraces, suggesting that the evaluation of breeding materials under non-stressed conditions should be continued. Unlike the modern cultivar, the landraces were low yielding, and less responsive to non-stressed environments for grain yield and yield attributes. The drought resistance indices, i.e. tolerance index (TOL) and stress susceptibility index (SSI), were better in landraces than breeding lines, while the drought tolerance indices, i.e. stress tolerance index (STI) and drought response index (DRI), were better in breeding lines. In contrast with landraces, the modern cultivar and the breeding lines showed significant changes for both grain yield and drought tolerance.

Analysis of Genotype-by-Environment Interaction for Agronomic Traits of Durum Wheat in Iran

Grain yield of durum wheat (Triticum turgidum L. var. durum) under Mediterranean conditions is frequently limited by both high temperature and drought during grain filling. Genotype-by-environment (GE) interaction and genotype-by-trait (GT) data were analyzed for agronomic performance of durum wheat breeding lines. Data were obtained from 18 durum wheat breeding lines and two cultivar checks (Zardak and Sardari) for their agronomic performance under three different climate locations (moderate, warm and cold winters) and two moisture regimes (rainfed and two supplemental irrigations conditions) in two cropping seasons (2006 and 2007) in Iran. Analysis of GE interaction data based on multiple traits showed that the environment (combination of year-location- moisture regimes) effect was always the most important source of trait variation, accounting for 58.6 to 98.4% of the total variation. Biplot analysis of the studied traits revealed that (i) the locations tended to discriminate genotypes in dissimilar fashions, and (ii) the relationships among traits were not consistent over the locations, where they facilitated visual genotype comparisons and selection at each location.

Baking quality of emmer-derived durum wheat breeding lines

Durum wheat ( Triticum turgidum L. var. durum) is used predominantly for pasta products, but there is increasing interest in using durum for bread-making. The goal of this study was to assess the bread-making potential of 97Emmer19, an Emmer wheat ( Triticum turgidum L. var. dicoccum) and in breeding lines derived from crosses of 97Emmer19 with adapted durum wheat cultivars. 97Emmer19 and its progeny were evaluated in 2005 and 2006 along with five durum wheat cultivars. Three bread wheat ( Triticum aestivum L.) cultivars were included as checks to provide a baseline of bread making quality observed in high quality bread wheat cultivars. 97Emmer19 exhibited higher LV than all the durum wheat checks and approached the LV achieved with the bread wheat cultivar ‘AC Superb’. Breeding lines derived from 97Emmer19 had higher LV than those of the durum wheat checks, confirming that this trait was heritable. In general, durum wheat cultivars with elevated gluten strength and/or increased dough extensibility were noted to have higher LV. Dough extensibility appeared to be a more critical factor as gluten strength increased. These results indicate that there is potential to select for genotypes with improved baking quality in durum breeding programs.

Relationship between glutenin subunit composition and gluten strength measurements in durum wheat

AbstractDurum breeders use a range of techniques in the development of new cultivars. An important selection criterion is the rheological properties of semolina dough and durum wheat breeders use this criterion in the development of new cultivars using a range of techniques. Because of the need to process large numbers of genotypes encountered in breeding programs, methods that are inexpensive, rapid, require small amounts of sample and that correlate with semolina quality are desirable. Using breeding material, this study investigated the relationship between the glutenin subunit composition and two traditional tests of gluten strength, gluten index (GI) and mixograph. Two sample sets of durum wheat breeding lines and cultivars, one grown in Canada (n = 229) and the other grown in Australia (n = 139) were analysed for GI, mixograph and both high molecular weight (HMW) and low molecular weight (LMW) glutenin subunits by SDS‐PAGE. Nine different HMW and 14 different LMW allelic combinations were found. In the Canadian set, the most frequent LMW alleles were aaa, bba, caa and cfa while in the Australian set, caa was predominant. For the HMW subunits, the most common allelic groups were Glu‐A1c/Glu‐B1d (null, 6 + 8) and Glu‐A1c/Glu‐B1b (null, 7 + 8) with fewer numbers of Glu‐A1c/Glu‐B1e (null, 20) in both sample sets. LMW subunits were more important contributors to gluten strength than HMW subunits with the rank for higher GI according to the LMW allele (Canadian set) being caa = aaa > bba and aaa > cfa while HMW subunits 6 + 8 = 7 + 8 > 20. Similarly, using the mixograph, strength ranking for the LMW alleles was aaa > cfa = bba and HMW subunit 20 gave poorer rheological properties. For some samples with a good LMW allelic group a low GI was observed and vice versa. Further characterisation of the protein composition in these samples showed the GI results could be explained by polymeric/monomeric (P/M), glutenin/gliadin (Glu/Gli) and HMW/LMW ratios or the proportion of unextractable polymeric protein. © Crown in the right of the State of New South Wales, Australia; and for the Department of Agriculture and Agri‐Food, Government of Canada, © Minister of Public Works and Government Services Canada 2005. Published for SCI by John Wiley & Sons, Ltd.

Effect of durum wheat (Triticum turgidum L. var. durum) semolina extraction rate on semolina refinement, strength indicators and pasta properties

Since the 1980s, there have been general trends in the durum wheat milling industry to higher semolina extraction rate, and in the pasta processing industry to the use of higher drying temperatures. During this time, specification of gluten strength by gluten index, mixograph mixing properties and alveograph parameters has also become widespread. These trends prompted this study of the appropriateness of protocols for quality testing of Canadian durum wheat breeding lines. Four cultivars with intrinsic differences in yellow pigment levels and gluten strength were grown in field plots in Swift Current, Saskatchewan for three consecutive years. A laboratory-scale milling procedure was modified to produce semolina at extraction rates from about 65% to about 80%. Milling to extraction rates above 65%, the extraction rate used routinely in quality testing of Canadian durum wheat breeding lines, had a major impact on semolina ash content and colour, but did not offer any advantage in ranking cultivars for either semolina yield or semolina refinement. Gluten strength, as measured by gluten index, was independent of semolina extraction rate. Dough strength, as measured by mixograph properties and alveograph properties, showed a tendency to weakening at high extraction, particularly for strong cultivars. Semolina was processed into spaghetti using low-temperature (LT), high-temperature (HT) and ultra-high-temperature (UHT) drying cycles. The firmness of cooked spaghetti was predominantly influenced by protein content. As a result, cultivars generally ranked in spaghetti firmness according to protein content. Regardless of drying cycle or cultivar, spaghetti firmness increased as drying temperature increased. Spaghetti dried at LT was less yellow than spaghetti dried at HT or UHT, probably due to thermal inactivation of the bleaching enzyme lipoxygenase at HT and UHT. Regardless of drying cycle, spaghetti became duller, more red and less yellow as extraction rate increased. For each spaghetti trait, cultivar ranking remained relatively constant regardless of extraction rate or drying temperature. On the basis of these results, there appears to be no advantage to increasing semolina extraction rate beyond 65% for evaluation of durum wheat milling performance, gluten strength or pasta properties. In addition, it appears that one drying cycle is adequate to reliably evaluate durum wheat lines for spaghetti colour and firmness. Key words: Durum wheat (Triticum turgidum L. var durum), milling, semolina, pasta, quality screening, gluten strength, colour, texture

Prediction of adaptability and yield stability of durum wheat genotypes from yield response in normal and artificially drought-stressed conditions

Adaptability, yield stability and yield reliability of durum wheat breeding lines are usually assessed through regional testing. The opportunity of partially substituting such testing by evaluation under normal and artificially drought-stressed rainfed conditions was investigated for a water-limited Italian region. Nine lines were grown at six sites for three seasons to assess adaptability across locations as Perkins and Jinks' slope of genotype regressions (β), stability across environments as Shukla's stability variance ( σ 2), mean yield ( Y), and Eskridge's reliability ( R) from Y plus σ 2. Heterogeneity of genotype regressions explained 54% of genotype-location interaction variation. The β values were strictly associated ( r = −0.99) with genotype scores on the first genotype-location interaction principal component (PC1), were not related to earliness of heading, and tended to negative correlation with plant stature that was hardly explainable in terms of resistance to lodging. Mean yield, PC1 score and rainfall of sites were correlated. The lines were also grown under normal and stress conditions at four sites for two seasons. The stress was established by placing metal channels between the rows that evacuated a portion of rainfall from the end of tillering stage onwards. Predictions of β, σ 2, Y and R, attempted respectively from slope of genotype-stress level interaction ( β P), β 2 P, mean yield across conditions ( Y P), and Y P plus β 2 P, were assessed as genetic correlation. Predictions based on β P and Y P computed over all test environments were all relatively good, whilst those based on data of individual seasons or locations were mostly inaccurate for σ 2, Y and R. High-yielding sites could better predict Y and R. Two seasons' data from one such site showed correlations of 0.60, 0.53, 0.72 and 0.75 for prediction respectively of β, σ 2, Y and R. Evaluation of advanced breeding lines under normal and artificially stressed conditions at a high-yielding site may prove useful for reducing the number of lines promoted to subsequent regional testing and/or restricting their regional testing to specific areas of adaptation.

A Rapid for Estimating Durum Wheat Gluten Quality1

Firmness of cooked pasta and tolerance to overcooking are important quality characteristics of products made from durum wheat (Triticum turgidum L.) semolina. Stronger gluten has been shown to be associated with greater cooked pasta firmness and overcooklng tolerance.Our objective teas to evaluate a new bread quality test for predicting gluten strength among durum wheat breeding lines. A wholemeal, sodium dodecyl sulfate (SDS)/ lactic acid solution ‐ sedimentation test requiring 6 g of wheat was compared to the micromixogram test requiring 20 g.Correlations between sediment volumes and mixogram scores were highly significant, and the coefficients of determination (r2) indicated that about 65% of the variation in micromixogram score was attributed to its association with sediment volume. Selection for strong gluten on the basis of sediment volume was 84% as successful as selection on the basis of micromixogram score. One person can, with adequate simple equipment, mill and evaluate at least 120 samples/day. We conclude that the SDS‐sedimentation test is a major advance in screening for gluten strength differences among small samples of durum wheat.