Durum Wheat Breeding Programs Research Articles

Univariate and multivariate genomic prediction for agronomic traits in durum wheat under two field conditions.

Genomic prediction (GP) has been evaluated in durum wheat breeding programs for several years, but prediction accuracy (PA) remains insufficient for some traits. Recently, multivariate (MV) analysis has gained much attention due to its potential to significantly improve PA. In this study, PA was evaluated for several agronomic traits using a univariate (UV) model in durum wheat, subsequently, different multivariate genomic prediction models were performed to attempt to increase PA. The panel was phenotyped for 10 agronomic traits over two consecutive crop seasons and under two different field conditions: high nitrogen and well-watered (HNW), and low nitrogen and rainfed (LNR). Multivariate GP was implemented using two cross-validation (CV) schemes: MV-CV1, testing the model for each target trait using only the markers, and MV-CV2, testing the model for each target trait using additional phenotypic information. These two MV-CVs were applied in two different analyses: modelling the same trait under both HNW and LNR conditions, and modelling grain yield together with the five most genetically correlated traits. PA for all traits in HNW was higher than LNR for the same trait, except for the trait yellow index. Among all traits, PA ranged from 0.34 (NDVI in LNR) to 0.74 (test weight in HNW). In modelling the same traits in both HNW and LNR, MV-CV1 produced improvements in PA up to 12.45% (NDVI in LNR) compared to the univariate model. By contrast, MV-CV2 increased PA up to 56.72% (thousand kernel weight in LNR). The MV-CV1 scheme did not improve PA for grain yield when it was modelled with the five most genetically correlated traits, whereas MV-CV2 significantly improved PA by up to ~18%. This study demonstrated that increases in prediction accuracy for agronomic traits can be achieved by modelling the same traits in two different field conditions using MV-CV2. In addition, the effectiveness of MV-CV2 was established when grain yield was modelled with additional correlated traits.

The first assessment of grain yield and associated traits in durum wheat across a decade in Nepal.

Rapid urbanization and evolving dietary preferences have heightened the demand for durum wheat and its derivatives in developing nations like Nepal. This study represents the first comprehensive exploration and evaluation of durum wheat genotypes in Nepal, addressing the escalating need for high-yielding varieties. The primary objective was to identify stable and prolific durum wheat lines for release, enhancing Nepal's durum wheat breeding program. Utilizing genotypes from CIMMYT's disease screening and yield nurseries from 2011/12 to 2020/21, a total of 132 genotypes, including international checks, underwent evaluation over ten years under the Alpha Lattice design. Results revealed significant variation among genotypes for grain yield and other traits, identifying high-yielding and stable lines suitable for Nepal. Heritability analysis highlighted moderate heritability for grain number per spike, thousand-grain weight, and grain yield. Cluster analysis identified distinct clusters with high grain yield and desirable agronomic traits. Disease incidence facilitated the selection of resistant lines, with DWK38 emerging as the highest grain yielder (4416.04 kg/ha). Overall, durum wheat lines from CIMMYT exhibited robust performance in Nepal, enabling the identification of superior lines with potential benefits for farmers and consumers. The study's implications include developing and releasing superior durum lines in Nepal, providing farmers with profitable alternatives amidst evolving food habits. In conclusion, the findings from this study provide a valuable foundation for future durum wheat breeding efforts in Nepal, guiding the selection of genotypes that are well-suited to the diverse environmental challenges of the region.

Feature engineering and parameter tuning: improving phenomic prediction ability in multi-environmental durum wheat breeding trials

Key Message Optimized phenomic selection in durum wheat uses near-infrared spectra, feature engineering and parameter tuning. Our study reports improvements in predictive ability and emphasizes customized preprocessing for different traits and models.The success of plant breeding programs depends on efficient selection decisions. Phenomic selection has been proposed as a tool to predict phenotype performance based on near-infrared spectra (NIRS) to support selection decisions. In this study, we test the performance of phenomic selection in multi-environmental trials from our durum wheat breeding program for three breeding scenarios and use feature engineering as well as parameter tuning to improve the phenomic prediction ability. In addition, we investigate the influence of genotype and environment on the phenomic prediction ability for agronomic and quality traits. Preprocessing, based on a grid search over the Savitzky–Golay filter parameters based on 756,000 genotype best linear unbiased estimate (BLUE) computations, improved the phenomic prediction ability by up to 1500% (0.02–0.3). Furthermore, we show that preprocessing should be optimized depending on the dataset, trait, and model used for prediction. The phenomic prediction scenarios in our durum breeding program resulted in low-to-moderate prediction abilities with the highest and most stable prediction results when predicting new genotypes in the same environment as used for model training. This is consistent with the finding that NIRS capture both the genotype and genotype-by-environment (G×E)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(G\ imes E)$$\\end{document} interaction variance.

Trend in yield and protein content relationship in a historical series of durum wheat varieties under rainfed and irrigated environments

Improving grain yield (GY) is a major goal of durum wheat breeding programs, and a high yield needs to be attained while preserving grain quality. The current study evaluated the changes caused by a breeding program on the association between GY and grain protein content (PC) in Moroccan durum wheat. Field experiments with six leading varieties released over three decades were conducted for three growing seasons under two water regimes. GY and PC were largely controlled by environmental effects, including both the growing season and water regime. The year of release and growing season effects were the predominant sources of variation in total chlorophyll content (TCC). A significant increase in GY with the year of release was observed under irrigated conditions, whereas a significant increase in PC over time was noted under rainfed conditions. In addition, a negative correlation was revealed between GY and PC, which was significant only in the rainfed trials. Similarly, a significant and positive association was noted between PC and TCC within the rainfed trials, but not in the irrigated trials. Based on GGE (genotype main effect plus genotype ​× ​environment interaction) biplot analysis, the new varieties ‘Marouane’ and ‘Faraj’ were identified as desirable varieties in terms of GY and PC close to the ‘ideal genotype’. These results indicated that when grown under current irrigated conditions, new varieties improved by the Moroccan breeding program showed better GY performance than old varieties.

Durum wheat (Triticum turgidum L. var. durum) root system response to drought and salt stresses and genetic characterization for root-related traits.

Abiotic stresses such as drought and salt are significant threats to crop productivity. The root system adaptation and tolerance to abiotic stresses are regulated by many biochemical reactions, which create a complex and multigenic response. The present study aims to evaluate the diversity of root responses to cyclic abiotic stress in three modern durum wheat varieties and one hydric stress-tolerant landrace in a pot experiment from seedling to more advanced plant development stages. The genotypes responded to abiotic stress during the whole experiment very differently, and at the end of the experiment, nine out of the 13 traits for the landrace J. Khetifa were significantly higher than other genotypes. Moreover, single sequence repeat (SSR) genetic analysis revealed high polymorphism among the genotypes screened and interesting private alleles associated with root system architecture traits. We propose that the markers used in this study could be a resource as material for durum wheat breeding programs based on marker-assisted selection to increase the vegetal material with high drought and salt stress tolerance and to identify candidates with strong early vigor and efficient root systems. This study provides appropriate genetic materials for marker-assisted breeding programs as well as a basic study for the genetic diversity of root traits of durum wheat crops.

Genetic mapping of deoxynivalenol and fusarium damaged kernel resistance in an adapted durum wheat population

BackgroundFusarium head blight (FHB) infection results in Fusarium damaged kernels (FDK) and deoxynivalenol (DON) contamination that are downgrading factors at the Canadian elevators. Durum wheat (Triticum turgidum L. var. durum Desf.) is particularly susceptible to FHB and most of the adapted Canadian durum wheat cultivars are susceptible to moderately susceptible to this disease. However, the durum line DT696 is less susceptible to FHB than commercially grown cultivars. Little is known about genetic variation for durum wheat ability to resist FDK infection and DON accumulation. This study was undertaken to map genetic loci conferring resistance to DON and FDK resistance using a SNP high-density genetic map of a DT707/DT696 DH population and to identify SNP markers useful in marker-assisted breeding. One hundred twenty lines were grown in corn spawn inoculated nurseries near Morden, MB in 2015, 2016 and 2017 and the harvested seeds were evaluated for DON. The genetic map of the population was used in quantitative trait locus analysis performed with MapQTL.6® software.ResultsFour DON accumulation resistance QTL detected in two of the three years were identified on chromosomes 1 A, 5 A (2 loci) and 7 A and two FDK resistance QTL were identified on chromosomes 5 and 7 A in single environments. Although not declared significant due to marginal LOD values, the QTL for FDK on the 5 and 7 A were showing in other years suggesting their effects were real. DT696 contributed the favourable alleles for low DON and FDK on all the chromosomes. Although no resistance loci contributed by DT707, transgressive segregant lines were identified resulting in greater resistance than DT696. Breeder-friendly KASP markers were developed for two of the DON and FDK QTL detected on chromosomes 5 and 7 A. Markers flanking each QTL were physically mapped against the durum wheat reference sequence and candidate genes which might be involved in FDK and DON resistance were identified within the QTL intervals.ConclusionsThe DH lines harboring the desired resistance QTL will serve as useful resources in breeding for FDK and DON resistance in durum wheat. Furthermore, breeder-friendly KASP markers developed during this study will be useful for the selection of durum wheat varieties with low FDK and DON levels in durum wheat breeding programs.

Demonstration the effectiveness of NDVI with GGE biplot model in determination of high yielding durum wheat (Triticum durum Desf.) genotypes

The use of spectral indices such as normalised difference vegetation index (NDVI) is becoming an important element in the evaluation of physiological traits in cereal crops. Determining the correlation between spectral readings taken at different phenological stages of wheat plants and grain yield (GY) is crucial. This study aimed to demonstrate the effectiveness of NDVI in combination with the GGE biplot model in identifying high yielding durum wheat genotypes. Field experiments were conducted in multiple environments and growth stages to evaluate the relationship between NDVI and grain yield (GY). Twenty-five durum wheat genotypes were tested for two years under rainfed and supplementary irrigation conditions using a split plot experimental design. The results showed significant positive correlations between NDVI and GY, especially at the generative stages under rain-fed conditions. In contrast, NDVI at the grain-filling stage showed a weaker relationship with GY under supplemental irrigation. Genotypes exhibiting high NDVI values up to the stem elongation stage tended to have lower grain yields, emphasizing the importance of considering growth stage dynamics. GGE biplot analysis provided visual information on genotype-trait relationships, helping to identify genotypes with consistent performance in different environments. This study highlights that NDVI can be used to predict yield potential and guide selection in durum wheat breeding programs and the GGE biplot model serves as a valuable tool for genotype evaluation and selection.

Molecular Genetic Diversity of Local and Exotic Durum Wheat Genotypes and Their Combining Ability for Agronomic Traits under Water Deficit and Well-Watered Conditions.

Water deficit poses significant environmental stress that adversely affects the growth and productivity of durum wheat. Moreover, projections of climate change suggest an increase in the frequency and severity of droughts, particularly in arid regions. Consequently, there is an urgent need to develop drought-tolerant and high-yielding genotypes to ensure sustained production and global food security in response to population growth. This study aimed to explore the genetic diversity among local and exotic durum wheat genotypes using simple sequence repeat (SSR) markers and, additionally, to explore the combining ability and agronomic performance of assessed durum wheat genotypes and their 28 F1 crosses under normal and drought stress conditions. The investigated SSRs highlighted and confirmed the high genetic variation among the evaluated parental durum wheat genotypes. These diverse eight parental genotypes were consequently used to develop 28 F1s through a diallel mating design. The parental durum genotypes and their developed 28 F1s were assessed under normal and drought stress conditions. The evaluated genotypes were analyzed for their general and specific combining abilities as well as heterosis for agronomic traits under both conditions. The local cultivar Bani-Suef-7 (P8) is maintained as an effective combiner for developing shortened genotypes and improving earliness. Moreover, the local cultivars Bani-Suef-5 (P7) and Bani-Suef-7 (P8) along with the exotic line W1520 (P6) demonstrated excellent general combining ability for improving grain yield and its components under drought stress conditions. Furthermore, valuable specific hybrid combinations, W988 × W994 (P1 × P2), W996 × W1518 (P3 × P5), W1011 × W1520 (P4 × P6), and Bani-Suef-5 × Bani-Suef-7 (P7 × P8), were identified for grain yield and its components under drought stress conditions. The assessed 36 genotypes were grouped according to tolerance indices into five clusters varying from highly drought-sensitive genotypes (group E) to highly drought-tolerant (group A). The genotypes in cluster A (two crosses) followed by thirteen crosses in cluster B displayed higher drought tolerance compared to the other crosses and their parental genotypes. Subsequently, these hybrids could be considered valuable candidates in future durum wheat breeding programs to develop desired segregants under water-deficit conditions. Strong positive relationships were observed between grain yield and number of grains per spike, plant height, and 1000-grain weight under water-deficit conditions. These results highlight the significance of these traits for indirect selection under drought stress conditions, particularly in the early stages of breeding, owing to their convenient measurability.

Unlocking the genetic potential of Ethiopian durum wheat landraces with high protein quality: Sources to be used in future breeding for pasta production

AbstractThe content and composition of the grain storage proteins in wheat determine to a high extent its end‐use quality for pasta and bread production. This study aimed to evaluate the content and composition of the grain storage proteins in Ethiopian landraces and cultivars to contribute to future breeding toward improved pasta quality. Thus, 116 landraces and 34 cultivars originating from Ethiopia were grown in three locations, and the protein parameters were analyzed using size exclusion‐high performance liquid chromatography (SE‐HPLC). A considerable variation in the amount of the analyzed protein parameters was found. The genotypes, environments, and interactions contributed significantly (p < 0.001) to the differences obtained. The broad‐sense heritability was high (0.75–0.98) for all protein parameters except for unextractable small monomeric protein (uSMP). Using the principal component analysis (PCA) to evaluate the impact of protein parameters and using either PCA or unweighted pair group method with arithmetic mean (UPGMA) to assess the impact of the genetic composition, the cultivar group was found to form a separate cluster. This indicates that durum wheat improvement in Ethiopia has relied on exotic materials, which might result from a narrow genetic base. Unlike most landraces, most released cultivars showed a high and stable gluten strength across environments. Two landraces, G057 and G107, were found genetically distinct from the released cultivars but with high and stable gluten. The two selected landraces might be of extremely high value for future use in durum wheat breeding programs, as they might be adapted to wide‐ranging Ethiopian growing conditions, they might carry genes of relevance to withstand abiotic and biotic stresses, and they seem to hold essential protein properties, which might result in high‐quality grains for industrial processes.

A null allele of the polyphenol oxidase gene Ppo‐A1 in hexaploid wheat originates from tetraploid wheat

AbstractPolyphenol oxidase (PPO) has a major effect on the time‐dependent darkening of noodle products. Development of varieties with low PPO activity is one method to eliminate this problem and respond to the demands of consumers. Among the common wheat (Triticum aestivum L.) Ppo genes, Ppo‐A1 has the highest effect on grain PPO activity, and several Ppo‐A1 alleles with low or no activity have been reported, with the recently identified Ppo‐A1i allele being the most desirable allele. In this study, reverse‐transcription polymerase chain reaction analysis confirmed that this allele was not expressed and was therefore functionally null. We also determined that Ppo‐A1i has an approximately 3 kb insertion in the second intron. Taking advantage of the insertion sequence, we developed a new co‐dominant marker, PPO18Plus, capable of distinguishing Ppo‐A1a, Ppo‐A1b, and Ppo‐A1i. In addition, we determined that the Ppo‐A1i allele is identical to and originates from the Ppo‐A1g allele of tetraploid wheat. The durum wheat (Triticum turgidum ssp. durum (Desf.) Husn.) Ppo‐A1g allele has been used to improve pasta color in durum wheat breeding programs. Thus, the PPO18Plus marker developed here will be very useful in both hexaploid and durum wheat breeding programs.

Water stress effect on durum wheat (Triticum durum Desf.) advanced lines at flowering stage under controlled conditions

Drought stress is a key factor affecting Morocco's agricultural productivity. In order to adapt to climate change, it is crucial to select new genotypes which may be slightly but not significantly less efficient. Durum wheat (Triticum durum Desf.) is one of the most important and cereal crops that are impacted by drought. The objective of this research was to assess the performance of 16 durum wheat genotypes to drought stress. From the beginning of flowering stage until the beginning of seed maturity, three levels of water treatment were applied, corresponding to 100%, 66% and 33% of field capacity. Three agro-morphological, five physiological and three biochemical traits were investigated in those genotypes grown under controlled greenhouse conditions over two years (2020 and 2021), by following completely randomized design (CRD) with three replications. The results showed that stomatal conductance, relative water content, leaf area, leaf temperature, SPAD values, proline, soluble sugars, glycine betaine and yield traits were significantly (p < 0.05) affected by the water treatment. In all the genotypes, three advanced lines had the highest seed yield, namely, DYT1TAZI (12.75 g) with a 16.2% decrease from the control, DYT11TAZI (12.74 g, down 17.5%) and DYT5TAZI (12.26 g, down 19.24%), were found to be the most drought-tolerant, stable and productive having exhibited their highest performance in the absence and presence of drought stress. They had the best seed yield per plant (>12 g; p < 0.001) associated with the highest relative water content RWC (>50%; p < 0.001), chlorophyll content (>50 SPAD; p < 0.001), proline content (400μg/100 mg MF; P < 0.001), soluble sugars content (500μg/100 mg MF; P < 0.001), and stomatal conductance (>0.6 mol m-2s-1; p < 0.001). Therefore, these lines could be selected as relevant and valuable germplasms to be used in durum wheat breeding programs aiming to develop drought-tolerant and high-yielding varieties. High relative water content and stomatal conductance along with low leaf temperature can be taken as selection indices in this breeding program.

Estimating genetic diversity among durum wheat (Triticum durum desf.) landraces using morphological and SRAP markers

The durum wheat (Triticum turgidum L. ssp. durum Desf.) Landraces are a valuable source of natural germplasm for enhancing the genetic diversity of existing durum wheat cultivars. The study analyzed the genetic diversity of twenty-two durum wheat landraces including eight local Saudi landraces and fourteen introduced landraces using sixteen morphological descriptors and sequence-related amplified polymorphism (SRAP) markers. The results showed significant differences between the analyzed agro-morphological parameters and a large degree of genetic variation across the tested landraces. Principle components analysis (PCA) was used to determine agro-morphological relationships among different traits. The first six principal components (PCs) accounted for 78.47 % of the cumulative variability among 22 landraces. The PC1demonstrated variability in coleoptile anthocyanin coloration, straw pith, culm neck glaucosity, flag leaf glaucosity, ear glaucosity, and length of awn at tip relative to length of ear. Wheat landraces (L8, L14, L497, L569, L590, L594, L600, L601, and L602) showed increased diversity in dry region and contributed to PC1. A couple landraces had higher plant height (L12, L598, and L654), heading days (650, 656), and ear length (L12, L594, and L650) respectively. The dendrogram generated from the standardized morphological data separated the twenty-two durum wheat genotypes mainly into two clusters. The landraces 14, 600 and 602 grouped into separate cluster with strong correlation to ear glaucosity. Genetic diversity of these landraces was also evaluated using eight SRAP markers, with 482 amplified fragments and an average polymorphic information content (PIC) of 0.27. The dendrogram based on SRAP markers separated into two clusters with some diversified landraces (L8, 594, 602, 977, and L650). The Mantel test found no significant correlation (phenotypic or genetic) between 22 wheat durum landraces (r = 0.013, p = 0.84, =0.05). The results demonstrated the power of morphological and SRAP markers for detecting diversity among durum wheat landraces in the semi-arid region of Saudi Arabia. Thus, study provides insights into wheat diversity for better in-situ and ex-situ conservation and paves the road for their use in a Saudi durum wheat breeding program.

Genetic Mapping of Flavonoid Grain Pigments in Durum Wheat.

Pigmented cereal grains with high levels of flavonoid compounds have attracted the attention of nutritional science backing the development of functional foods with claimed health benefits. In this study, we report results on the genetic factors controlling grain pigmentation in durum wheat using a segregant population of recombinant inbred lines (RILs) derived from a cross between an Ethiopian purple grain accession and an Italian amber grain cultivar. The RIL population was genotyped by the wheat 25K SNP array and phenotyped for total anthocyanin content (TAC), grain color, and the L*, a*, and b* color index of wholemeal flour, based on four field trials. The mapping population showed a wide variation for the five traits in the different environments, a significant genotype x environment interaction, and high heritability. A total of 5942 SNP markers were used for constructing the genetic linkage map, with an SNP density ranging from 1.4 to 2.9 markers/cM. Two quantitative trait loci (QTL) were identified for TAC mapping on chromosome arms 2AL and 7BS in the same genomic regions of two detected QTL for purple grain. The interaction between the two QTL was indicative of an inheritance pattern of two loci having complementary effects. Moreover, two QTL for red grain color were detected on chromosome arms 3AL and 3BL. The projection of the four QTL genomic regions on the durum wheat Svevo reference genome disclosed the occurrence of the candidate genes Pp-A3, Pp-B1, R-A1, and R-B1 involved in flavonoid biosynthetic pathways and encoding of transcription factors bHLH (Myc-1) and MYB (Mpc1, Myb10), previously reported in common wheat. The present study provides a set of molecular markers associated with grain pigments useful for the selection of essential alleles for flavonoid synthesis in durum wheat breeding programs and enhancement of the health-promoting quality of derived foods.

Durum wheat (Triticum turgidum L. var. durum Desf.) landraces and their potential for enhancing agro-physiological characteristics and stability performance in breeding programs

Context Landraces are a potential source of genetic diversity and provide useful genetic resources to cope with the current and future challenges in crop breeding. Aims The main objectives of this study were to identify superior landraces with good levels of agro-physiological traits, and high mean yield and stability performance. Methods We evaluated a worldwide diversity panel of 196 durum wheat accessions originating from Iran and 17 other different countries along with four check varieties using an alpha-lattice design with two replications under drought and irrigated conditions in two cropping seasons. Key results The results showed that the variance due to genotype and environment for all measured traits; and genotype-by-environment interaction for grain yield were significant (P &lt; 0.01). The genotype-by-traits (GT) biplot analysis revealed that the relationships of traits with grain yield were affected by environment, but some consistent correlations among studied traits were observed. Chlorophyll content, earliness and 1000-kernel weight positively correlated with mean yield under drought condition, whereas greenness index, plant height, days to heading and maturity positively correlated with yield under irrigated condition. The results verified that clustering pattern of durum diversity panel did not follow the grouping of accessions according to their geographic origins. Using the genotype plus genotype-by-environment (GGE) biplot method, accessions with high yield and stability performance were identified. Conclusions The results provide the possibility to select a subset of best accessions based on the traits studied, for further evaluations under drought and irrigated conditions. Implications The findings are useful for selective breeding for specific traits as well as for enhancing the genetic basis of the durum wheat breeding program.

Cytogenetic and genomic characterization of a novel tall wheatgrass-derived Fhb7 allele integrated into wheat B genome.

We identified and integrated the novel FHB-resistant Fhb7The2 allele into wheat B genome and made it usable in both common and durum wheat breeding programs without yellow flour linkage drag. A novel tall wheatgrass-derived (Thinopyrum elongatum, genome EE) Fhb7 allele, designated Fhb7The2, was identified and integrated into the wheat B genome through a small 7B-7E translocation (7BS·7BL-7EL) involving the terminal regions of the long arms. Fhb7The2 conditions significant Type II resistance to Fusarium head blight (FHB) in wheat. Integration of Fhb7The2 into the wheat B genome makes this wild species-derived FHB resistance gene usable for breeding in both common and durum wheat. By contrast, other Fhb7 introgression lines involving wheat chromosome 7D can be utilized only in common wheat breeding programs, not in durum wheat. Additionally, we found that Fhb7The2 does not have the linkage drag of the yellow flour pigment gene that is tightly linked to the decaploid Th. ponticum-derived Fhb7 allele Fhb7Thp. This will further improve the utility of Fhb7The2 in wheat breeding. DNA sequence analysis identified 12 single nucleotide polymorphisms (SNPs) in Fhb7The2, Fhb7Thp, and another Th. elongatum-derived Fhb7 allele Fhb7The1, which led to seven amino acid conversions in Fhb7The2, Fhb7Thp, and Fhb7The1, respectively. However, no significant variation was observed in their predicted protein configuration as a glutathione transferase. Diagnostic DNA markers were developed specifically for Fhb7The2. The 7EL segment containing Fhb7The2 in the translocation chromosome 7BS·7BL-7EL exhibited a monogenic inheritance pattern in the wheat genetic background. This will enhance the efficacy of marker-assisted selection for Fhb7The2 introgression, pyramiding, and deployment in wheat germplasm and varieties.

Combining ability for quantitative traits related to productivity in durum wheat.

The present study was to determine the nature of gene action and combining ability of six quantitative traits related to productivity of five varieties and ten hybrid combinations of durum wheat. Five modern durum wheat varieties were used in diallel crosses as parents. The study includes three F1 and two F2 generations. The experiments were done in a randomized block design in three replications during three years. Significant differences between the genotypes in both generations was found for all the traits. The general combining ability and specific combining ability showed reliability in both generations. Obtained results suggests that breeding schemes should include both types of genetic effects in order to improve productivity components. The ratio of variances showed that general combining ability has a greater influence on the inheritance of plant height, spike length and thousand kernels weight. For productivity tillering capacity, number of spikelets per spike and kernels weight per spike, specific combining ability has a great impact in inheritance. For thousand kernels weight a redetermination of the genetic formula was established in both generations. Durum wheat varieties Deni, Superdur and Progres were found to be the best general combinators for studied productivity elements. The most valuable cross combinations were Deni × Superdur, Superdur × Predel and Progres × Predel. Parental wheat varieties and progenies from these crosses can be used for improving productivity components and for increasing yields in durum wheat breeding programs.

Multivariate analyses of Ethiopian durum wheat revealed stable and high yielding genotypes.

Improving crop adaptation and stability across diverse and changing environmental conditions is essential to increasing grain yield per unit area. In turn, this contributes to meeting the increasing global food demand. Nevertheless, a number of factors challenge the efficiency of crop improvement programs, of which genotype-by-environment interaction (GEI) is one of the major factors. This study aimed to evaluate the performance and phenotypic stability of 385 Ethiopian durum wheat landraces and 35 cultivars; assess the pattern of genotype by environment interaction (GEI) effect, and identify stable and high-yielding landraces or cultivars using the additive main effect and multiplicative interaction (AMMI) and genotype main effect plus genotype by environment interaction biplot (GGE-biplot). The experiment was laid out in an alpha lattice design with two replications at five test sites (Akaki, Chefe Donsa, Holeta, Kulumsa, and Sinana). The combined analysis of variance revealed highly significant effects (P ≤ 0.01) of environments (E), genotype (G), and GEI on a phenotypic variation of traits evaluated, including grain yield. For all traits, the amount of phenotypic variance and GEI explained by the GGE biplot was higher than in AMMI2, but both exhibited significant effects of E and GEI on the genotypes. The AMMI model identified G169, G420, G413, G139, G415, G416, G417, and G418 as stable genotypes across testing sites. Whereas, the GGE biplot identified G169, G420, G415, G139, G106, G412, G413, and G417 as both high-yielding and stable across test sites. Hence, genotypes identified as stable and high yielding in the present study could be used in a durum wheat breeding program aimed at identifying genes and molecular markers associated with the crop’s productivity traits as well as developing stable and high-yielding cultivars for use in East Africa and beyond.

Phenotypic Variability, Heritability and Associations of Agronomic and Quality Traits in Cultivated Ethiopian Durum Wheat (Triticum turgidum L. ssp. Durum, Desf.)

Quality is an important aspect of durum wheat in the processing sector. Thus, recognizing the variability of quality and agronomic traits and their association is fundamental in designing plant breeding programs. This study aimed to assess the variability, heritability, genetic advance, and correlation of some agronomic and quality traits among 420 Ethiopian durum wheat genotypes and to identify the promising genotypes with distinct processing quality attributes to produce superior quality pasta. The field experiment was conducted at two locations (Sinana and Chefe Donsa) using an alpha lattice design with two replications. Analysis of variance, chi-square test, and Shannon–Weaver diversity index revealed the existence of highly significant (p &lt; 0.001) variation among genotypes for all studied traits. The broad-sense heritability values were ranging from 46.2% (days to maturity) to 81% (thousand kernel weight) with the genetic advance as a percent of the mean ranging from 1.1% (days to maturity) to 21.2% (grain yield). The phenotypic correlation coefficients for all possible pairs of quantitative traits showed a significant (p &lt; 0.05) association among most paired traits. The gluten content (GC) and grain protein content (GPC) were negatively correlated with grain yield and yield-related traits and positively associated with phenological traits, while yield and phenological traits correlated negatively. The frequency distributions of amber-colored and vitreous kernels, which are preferable characters of durum wheat in processing, were highly dominant in Ethiopian durum wheat genotypes. The identified top 5% genotypes, which have amber color and vitreous kernel with high GC and GPC content as well as sufficient grain yield, could be directly used by the processing sector and/or as donors of alleles in durum wheat breeding programs.

Genetic variability, divergence, and path coefficient analysis of yield and yield related traits of Durum wheat (Triticum turgidum l. var. Durum) genotypes at Jamma district, south wollo zone, amhara region, Ethiopia

Durum wheat (Triticum turgidum L. var. durum) is a member of the Poaceae family and tetraploid (genomes of AABB) with 28 chromosomes (2n=4x=28). Narrow genetic variability was a problem to develop genotypes with better adaptation to different agro-ecologies. Therefore, the objective of this study was to investigate the genetic variability, divergence, and path coefficient analysis of durum wheat genotypes by using morphological traits and identifying essential yield-related traits of durum wheat, and to identify promising candidate genotypes to be used in future durum wheat breeding program. The study was carried out on 81 genotypes and the experiment was laid out in a triple lattice design with an arrangement of 9 x 9 x 3 treatment, which made 243 experimental units. Results obtained on genetic variability, path coefficient, and genetic divergent analysis among yield-related traits are presented here under the present study. Generally, the present study revealed the existence of significant genetic variability among the tested genotypes for different traits helpful for direct and indirect selection. This study recommended that the potential durum wheat genotypes 214552, 208150, 238516, 5645, Mekuye, 236984, 7960, 7152, 231599, and 208242 could be used for durum wheat breeding programs for yield and yield component traits improvement under similar agro-ecologies.

Assessment of the suitability of Triticum turgidum accessions for incorporation into a durum wheat breeding program

Assessment of the suitability of Triticum turgidum accessions for incorporation into a durum wheat breeding program