Improved Bread Wheat Research Articles

AMMI analysis of elite bread wheat (Triticum aestivum L.) selections for genotype by environment interaction and stability of grain yield in Southern Ethiopia.

Smallholder wheat farmers of Ethiopia frequently use landraces as seed sources that are low yielders and susceptible to diseases due to shortage of seeds of adapted improved bread wheat varieties. Developing novel improved varieties with wider adaptability and stability is necessary to maximize the productivity of bread wheat. Hence, a multi-location field trial was conducted across four locations in south Ethiopia during the 2022/23 main cropping season with the objective of estimating the magnitude of genotype by environment interaction (GEI) effect, and determine the stable genotype among the 10 Ethiopian bread wheat advanced selections using a randomized complete block design (RCBD) with three replications. The data recorded from all plots on 13 agronomic traits and the three wheat rust diseases were computed using appropriate statistical software. The results showed that individual and combined analysis of variance (ANOVA) exhibited the presence of highly significant variability (P<0.01) among the locations, genotypes, and GEI effects for most of the traits including grain yield. The additive main effects and multiplicative interaction (AMMI) ANOVA for main effects; location, genotype and GEI revealed significant variation among the selections with 82.0%, 8.7% and 9.3% share of sum square variation, respectively. The genotype plus genotype by environment interaction (GGE) bi-plot analysis explained 92.44% of the total variation observed. AMMI and GGE-biplot analyses indicated G11, G9, G10, and G8 as high yielders and well-adaptive in the favourable locations. AMMI stability value (ASV) and Yield stability index (YSI) showed G5 and G8 as highly stable and adaptive selections across locations. Overall, the study identified that G8 as the most stable and adaptive selection, while G11 was the top yielder cultivar across locations. Therefor it was suggested that seeds of G8 can be grown across all the locations, whereas G11, G9, and G10 can be grown in the favourable environments and similar agro-ecologies in the east African region.

Optimum Determination of NPSB Fertilizer Rates on Bread Wheat (&amp;lt;i&amp;gt;Triticum asetivum.L&amp;lt;/i&amp;gt;) Varieties at Degam District of North Shewa Zone, Oromia

The field experiment was conducted at Degam district during main cropping season to investigate the response of bread wheat varieties to NPSB fertilizer rates and identify its economic benefit. Factorial combination of three improved bread wheat varieties (Danda’a, Hidase and Kakaba) and six fertilizer rates [Control, 50, 100, 150, 200 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; NPSB fertilizer each supplemented with 92 kg N ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; and 64/20 kg NP ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; (Blanket recommendation) were laid out in randomized complete block design with three replications. The highest NKS (54.9), AGBM (13.8 tons ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;), SY (9.4 tons ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) and GY (4549kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) were recorded from 200 kg NPSB fertilizer. Among the varieties the highest NKS (54.3) from Danda’a, TKW (49.3 g) and GY (3351kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) were recorded from Hidase variety. Variety Kakaba score the highest PH (102.5 cm) and PNT (5 per plant) with combination of 200 kg and 150 kg NPSB fertilizer respectively and reached days to heading and maturity earlier than Danda’a and Hidase. In general, the economic feasibility of the fertilizer over varieties combination indicated that application of 200 kg NPSB ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;to all varieties Hidase, Danda’a and Kakaba resulted in maximum marginal rates of return 640.14 %, 604.81% and 481.47%, with a net benefit of 97993, 88596, and 82996 ETB respectively. Although, application of 200 kg NPSB ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; led to the highest MRR for the Hidase variety as compared to all other treatments and with about a total of 9397 ETB net benefit increment. Therefore, application of 200 kg of NPSB in supplement of 92 kg N ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; fertilizer with Hidase variety was the best producing economically profitable with acceptable grain yield.

The use of the species Triticum petropavlovskyi Udacz. et Migusch. to expand the genetic diversity of spring bread wheat

Background. The species Triticum petropavlovskyi Udacz. et Migusch. has a number of positive traits, but has rarely been used in breeding programs to improve bread wheat cultivars. The introgression of genetic material from this species into the Triticum aestivum L. gene pool will not only expand the genetic diversity of bread wheat with a set of traits valuable for breeders, but also help to analyze the expression of genes from T. petropavlovskyi in a new genetic environment. Materials and methods. Spring bread wheat lines L163 and L164 produced with the participation of bread wheat cv. ‘Voevoda’ and an accession of T. petropavlovskyi were target materials of the study. Conventional methods were applied to perform phenological, phytopathological, genetic, and bread quality evaluations. Statistical processing of the resulting data was carried out using the Agros-2.10 software. Results. L163 and L164 were studied for their morphological and phenological indicators, resistance to pathogens, productivity, and grain quality. Differences in a number of traits between the lines and the recipient cultivar were observed. The introgression of the T. petropavlovskyi genetic material into bread wheat showed both positive and negative effects on some agronomic characteristics. L163 was identified for its resistance to the pathogens of leaf rust and powdery mildew, and tolerance to cereal aphids. It combined high productivity with an increased grain protein content compared to the recipient cultivar. In addition, this line demonstrated good rheological properties of its dough. Conclusion. Merging genetic materials from T. petropavlovskyi and bread wheat cv. ‘Voevoda’ made it possible to produce lines with a set of positive characteristics. The selected line, L163, combined effective resistance to a number of diseases, high grain productivity, and good breadmaking qualities, so it was included in the breeding process.

Effects of NPS Fertilizer Rate on Yield and Yield Components of Bread Wheat Production in Degem District, North Shewa Zone, Oromia, Ethiopia

Productivity of wheat was low due to depleted soil fertility and the blanket use of fertilizers. Fertilizer is the most vital input, contributing significantly to final wheat yields although wheat yields have long been low due to a lack of soil test-based site-specific fertilizer recommendations. This study aimed to determine an economically appropriate rate of NPS fertilizer based on calibrated Phosphorus for bread wheat production in the Degem district. The experiments laid out in randomized complete block design (RCBD) with three replications. The treatments were based on already determined Phosphorous critical and requirement factors and consisted of 100% Pc from TSP fertilizer, 25%, 50%, 75%, and 100% Pc from NPS fertilizer and control (without fertilizer). The phosphorus requirement factor (Pf) (5.85), phosphorus critical (Pc) (22 ppm), and optimum nitrogen optimum nitrogen (92 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) were used from previous studies. Improved bread wheat variety senete was used at 150 kg/ ha seeds rate. The results of a statistical analysis of variance demonstrated that NPS fertilizer rates based on calibrated phosphorus had significant effects on bread wheat production. Partial budget analysis shows the maximum net benefit (101,570.65 Birr ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;) with an acceptable marginal rate of return (MRR) (932’52 %) through the application of 75% of Pc from NPS with optimum nitrogen fertilizer use. Consequently, 75% Pc from NPS should be used in the Degem district for bread wheat production, with the optimum nitrogen. Thus, further scaled-up and demonstration of the technologies for bread wheat production in the Degem district.

Optimum Determination of NPSB Fertilizer Rates on Bread Wheat (Triticum asetivum L.) Varieties

The field experiment was conducted at Degam district during main cropping season to investigate the response of bread wheat varieties to NPSB fertilizer rates and identify its economic benefit. Factorial combination of three improved bread wheat varieties (Danda’a, Hidase and Kakaba) and six fertilizer rates [Control, 50, 100, 150, 200 kg ha-1 NPSB fertilizer each supplemented with 92 kg N ha-1 and 64/20 kg NP ha-1 (Blanket recommendation) were laid out in randomized complete block design with three replications. The highest NKS (54.9), AGBM (13.8 tons ha-1), SY (9.4 tons ha-1) and GY (4549kg ha-1) were recorded from 200 kg NPSB fertilizer. Among the varieties the highest NKS (54.3) from Danda’a, TKW (49.3 g) and GY (3351kg ha-1) were recorded from Hidase variety. Variety Kakaba score the highest PH (102.5 cm) and PNT (5 per plant) with combination of 200 kg and 150 kg NPSB fertilizer respectively and reached days to heading and maturity earlier than Danda’a and Hidase. In general, the economic feasibility of the fertilizer over varieties combination indicated that application of 200 kg NPSB ha-1to all varieties Hidase, Danda’a and Kakaba resulted in maximum marginal rates of return 640.14 %, 604.81% and 481.47%, with a net benefit of 97993, 88596, and 82996 ETB respectively. Although, application of 200 kg NPSB ha-1 led to the highest MRR for the Hidase variety as compared to all other treatments and with about a total of 9397 ETB net benefit increment. Therefore, application of 200 kg of NPSB in supplement of 92 kg N ha-1 fertilizer with Hidase variety was the best producing economically profitable with acceptable grain yield.

Milling and Bread-Making Traits Associated with Grain Hardness in Ethiopian Bread Wheat Varieties Grown Under Bale Condition

Many food processing industries utilizing bread wheat as a raw material are being established in the country. As a result, information on physico-chemical characteristics to match end use quality is very essential. In line with this, the current study was initiated with objectives to characterize physico-chemical properties in relation to bread making quality and to classify bread wheat cultivars as soft and hard wheat based on data generated. The grain of 44 Ethiopian improved bread wheat cultivars were collected from different agricultural research centers in the country and grown under rain fall condition at two locations (Ginnir and Sinana on station) during Bona (July-Jan., 2015/16 and 2016/17) growing season and analyzed for grain physical and flour chemical quality characteristics. The experiment was laid out in RCBD with three replications. Result of analysis of variance indicated that, there is significant variations in all quality parameters considered among cultivars. Grain physical characteristics, such as thousand kernel weight (TKW), percent vitreous kernel (%Vk), were showed highly significant difference (P&amp;lt;0.01) due to cultivars. Grain chemical quality as expressed by protein quantity (%P) and quality, percent gluten index (% Gl), Zeleny index (Zl), have also shown highly significant difference (P&amp;lt;0.01) due to genotypes. In addition, strong environmental variation was observed on measured quality characters. The present results indicated that there is huge genetic variation among Ethiopian wheat varieties for quality traits considered in this study.

Drivers of female farmers’ adoption of improved bread wheat varieties in Emba Alaje district, Northern Ethiopia

Drivers of female farmers’ adoption of improved bread wheat varieties in Emba Alaje district, Northern Ethiopia

Genetic variability and evaluation of water-deficit stress tolerant of spring bread wheat genotypes using drought tolerance indices

Water deficit stress is one of the most important environmental factors that reduce grain yield in bread wheat. Despite the recent progress in breeding this plant, there is still a need to improve bread wheat cultivars that tolerate water stress in the country. In the current research, 100 genotypes of spring bread wheat during the years 2020–2021 and 2021–2022 in two conditions of non-stress and water deficit stress in the form of a simple 10x10 lattice square design at the beginning of flowering in Gachsaran Research Center located in the south of Iran. Eight quantitative indices of tolerance to water deficit were calculated. Principal component analysis (PCA), hierarchical cluster analysis (HCA), analysis of variance, and Pearson correlation were carried out in this study. According to the data, significant genotypic variation was seen among genotypes for both individual yield and drought indices. Geometric Mean Productivity (GMP) recorded the lowest coefficient of variation (CV) value with 10.6 %, while Tolerance Index (TOL) recorded the highest CV value with 45.4 %. The heritability of several of the indices is moderate to high; the Stress Susceptibility Index (SSI) has the greatest heritability at 0.96. Four distinct clusters were formed from the 100 genotypes. PC1 and PC2 make up 98.4 % of the total variance. Specifically, PC1 covers 68.9 %, while PC2 accounts for the remaining 29.5 %. These chosen genotypes will act as parent plants in breeding initiatives to create novel varieties resistant to drought.

Pre-Extension Demonstration of Improved Bread Wheat Technologies at Highlands of Guji Zone, Oromia, Ethiopia

Increment of human population with the depletion of natural resources is challenging agriculture-based economy of developing countries. Hence, it is mandatory to find possible solutions to feed the increasing population. Ethiopian government has a vision the motto of food self-sufficiency by wheat production. for surplus production breeders have released many bread wheat varieties for different agroecologies. Therefore, released variety must be extended to the end users. This activity was proposed to evaluate bread wheat varieties at highlands of Guji zone. Three districts were selected based their wheat production potential. Sinja, Wane and Sanate bread wheat varieties were demonstrated on 10mx10m of 21 farmers’ land. Training and mini field day was organized for bread wheat promotion in selected districts. Descriptive statistics and cost-benefit analysis were used to analysis the data. The result showed that highest yield of 28.71qt/ha was harvested from Sanate followed by Wane (26.29 qt/ha) and Sinja (23 qt/ha) varieties. Production of Sanate, Wane and Sinja in highlands of Guji zone could generate 55489 birr/ha, 61263 birr/ha and 49846 birr/ha, respectively. Regardless of higher yield of Sanate experimental farmers preferred Wane variety as its color attract the market demand. Farmers witnessed the higher yield, good return and acceptance of Wane variety. Hence, Wane variety should be disseminated in highlands of Guji zone through pre scaling up and large scale production.

Evaluation of some Egyptian and Iraq Wheat (Triticum aestivum L.) Genotypes and Estimate of its Genetic Statistical Parameters

Seventeen bread wheat genotypes were evaluated involving seven Egyptian genotypes (Yakora, 13-ssd-43, Sahel 1, Gemiza 7, Gemiza 11, Sides12 and Giza 168) and ten Iraqi genotypes (Ibba 95, Ibba 99, Sham 6, Adana, Tamros 3, Jihan, Latifia, Buhooth 22, Rashid and Abu Ghraib) to estimate their variations, correlations, coefficients of differences (environmental, genetic, phenotypic) and heritability in the broad sense. The experiment was carried out in crop field farm - Faculty of Agriculture - Tikrit University. 11/15/2018, with randomizing complete block design. The genotype of Gemiza 7 exhibited superiority in both, the number of kernels/ spike and grain yield/ plant (58.53 kernels and 24.65 g), respectively. 13-ssd-43 and Sham 6 for number of spikes /plant and grain yield/ plant reached 11.83 and 10.74 spikes /plant, 24.28 and 23.16 g, respectively. This does not belong to the wide genetic diversity in addition to the occurrence of these structures in different cluster groups and with a genetic dimension. It can be considered a parent in future breeding and improvement programs. On the other hand, the number of spikes plant shown with the coefficient of genetic and phenotypic variation can be considered of high value for heritability, and genetic improvement can be regarded as a tool for improving bread wheat in the near future.

Farmers’ Varietal Perception towards Improved Bread Wheat Technologies in Ethiopia: an Implication for Bread Wheat Technology Development

This study was proposed to analyze farmers’ varietal perception of bread wheat. From Meket district, four kebeles were randomly selected to achieve the above objective. The study uses cross-sectional data collected from randomly selected 214 farming households through an interview schedule. Fourteen Likert items were included in two categories as advantages and disadvantages of the technology. Five-point Likert scale was used to analyze varietal perceptions. One-way ANOVA was employed for testing the overall mean differences among bread wheat technology adoption categories. In addition, the Relative Importance Index (RII) was used to analyze item relative importance. Farmers supported improved bread wheat varieties for specific attributes such as, high marketability, early maturity, better grain yield, grain color, food quality, and storability were found to be taking the average score of 4.43, 4.43, 4.33, 4.01, 3.85, 3.45, and 3.26, respectively. Whereas, improved bread wheat varieties were perceived to be unsuitable for shattering problems, straw quality, and low yield performances in poor soil types. Therefore, breeding objectives should be oriented towards improving bread wheat variety traits related to shattering and straw quality. Limitation of labor is one of the major reasons for the low adoption rate of row planting. Hence, machinery should be carried out to promote row planting of bread wheat. Moreover, the study indicates the need to entertain farmers’ perception of bread wheat technologies for creating wider adoption.

Application of Nano Chitosan-glycinebetaine for Improving Bread Wheat Performance under Combined Drought and Heat Stresses

Application of Nano Chitosan-glycinebetaine for Improving Bread Wheat Performance under Combined Drought and Heat Stresses

Comparative study of standard heterosis for yield and its attributes in bread wheat under two different water regimes

AbstractWater stress conditions have occurred in the past in various places of the world, affecting the yield and production of numerous crops, including wheat. The aim of this research was to estimate standard heterosis under two different water regimes for grain yield and its attributes in 33 crosses, which were obtained by crossing 11 lines and 3 testers in a Line × Tester mating design. The best cross combinations for yield and contributing traits under irrigated condition were C4, C8, C33, C24, and C23, compared to both checks HD2967 and PBW660. Whereas, in rainfed condition, C18, C14, C26, C21, and C20 crosses were superior to the checks. For both irrigated and rainfed conditions, the best cross combinations identified were C29, C15, C32, C2, and C31. As a result, these cross combinations could be used in wheat breeding programmes to improve bread wheat genotypes for increased grain yield, agro-morphological features, and water stress tolerance. The presence of high heterosis for yield-contributing traits not only aids in the development of hybrids by exploiting heterosis but also in the production of transgressive segregants to develop elite lines.

Sources of bread wheat (Triticum aestivum L.) seed in northwest Ethiopia

Smallholder farmers in Ethiopia are involved in multiple seed sources to access bread wheat seed. The present study was conducted in Baso Liben district, northwest Ethiopia, with the objectives of identifying the existing seed sources, factors affecting the use of improved bread wheat seed, and assessing practitioners’ (farmers and experts) suggestions to improve the existing bread wheat seed sources. Both quantitative and qualitative data were collected from 108 farmers and five local experts using semi-structured questionnaires and focus group discussions. The data were analyzed using descriptive statistics and a line-by-line examination of the transcripts of the FGDs. Results revealed that both formal and informal seed sources are available in the study area where farmers can access bread wheat seed. 41.5% of farmers utilized farm-saved seeds from the previous cropping season. The rest was accessed from neighboring farmers (11.4%), relatives (7.5%), and formal seed suppliers (39.6%). Yield advantage, disease tolerance, market value, and food quality were found to be the most common criteria in making the decision to use improved bread wheat varieties. The study confirms that both formal and informal seed sources are important in improving seed access to farmers. Hence, the importance of informal seed sources should be well-considered in policy development. Moreover, the government and development partners need to develop a mechanism to integrate both the formal and informal seed systems to improve seed availability.

Optimizing time and split application of nitrogen fertilizer to harness grain yield and quality of bread wheat (Triticum Aestivum L.) in northwestern Ethiopia.

Improper nitrogen application time during the crop growing period is one of the most limiting factor for wheat production. A field experiment was conducted in Northwestern Ethiopia with the objective of determining the appropriate N fertilizer application time for improving bread wheat production. Twelve treatments (½ urea at 50% emergence + ½ urea at tillering, ½ urea at tillering + ½ urea at booting, 1/3rd urea at 50% emergence + 1/3rd urea at tillering + 1/3rd urea at booting, 2/3rd urea at tillering + 1/3rd urea at booting, all urea at tillering, all urea at booting, all N at tillering, all N at booting, ½ N at sowing+ ½ N at tillering, ½ N 50% emergence + ½ N at tillering, 1/3rd N at 50% emergence + 1/3rd N at tillering + 1/3rd N at booting, ½ N at tillering + ½ N at booting) were lied out in randomized complete block design (RCBD) with three replications. The study showed that wheat grain yield and protein content was highly influenced by the environment and indirectly correlated with each other as affected by N time of applications. The grain yield at Adet, Wonberema and Debre Elies was increased by 31%, 14% and 18%, respectively when N was applied with DAP at sowing over the blanket recommendation. At all locations, grain protein content decreased as the number of N split application increased 1 to 3 times. Thus, depending on the purpose of the producers, it can be concluded that application of ½ urea at 50% emergence + ½ urea at tillering with the application of DAP at sowing gave maximum wheat grain yield, while optimum grain protein content was obtained when N was applied after the crop is emerged and would be used in most dominant wheat producing areas of northwestern Ethiopia. Further study should be conducted on split application of blended fertilizers (NPS, NPSBZN etc.).

Post-anthesis photosynthetic attributes and N-P-K status of standard and emmer wheats respond differently to nitrogen supply

Impact of nitrogen (N) supply on photosynthesis and N, P, and K status of wheat, particularly ancient wheats lacks clarity. Hence, clarification of post-anthesis photosynthesis and N, P, and K status of ancient emmer compared to the improved durum and bread wheats was aimed at. Five field-grown ancient emmer, one improved durum and an improved bread wheat exposed to a wide range of N fertilizer (i.e. 0, 25, 50, and 75 kg ha−1 N) were tested in two consecutive years. Chlorophyll and carotenoids concentrations of the emmer and improved wheats were increased by 39–63% and 29–45%, respectively in response to N supply. Mesophyll conductance and net photosynthetic rate of the improved bread wheat were increased by 150% and 60%, respectively, with increase in N supply, but those of the emmer wheats were decreased in response to the medium (0–43%) and high N (0–37%) supplies. Emmer wheat out-numbered the improved wheats in terms of mesophyll conductance and net photosynthetic rate under the low N supply but the reverse was true with the high N supply. Leaf (1–2.2, 3.2–7.7, and 16.8–35 mg g−1, respectively) and grain (2.38–6.4, 5.6–12.1, and 20.5–28.9 mg g−1, respectively) P, leaf N, and grain K concentrations responded positively to the N supply and emmer wheats equaled or exceeded those of the improved wheats particularly when grown in the absence of high N supplies. The presented data indicates that ancient emmer wheats are potent to be employed to incorporate nutrient-acquiring traits into the modern wheats.

Adaptability Study of Yield and Yield Related Trait Performance of Improved Bread Wheat (Triticum aestivum L.) Varieties in North Shewa Zone Oromia, Ethiopia

Bread Wheat (Triticum aestivum L.) is an important cereal crop, which receives the most attention of specialists in plant breeding and production as worldwide. The Knowledge of the interaction between genotypes and environment with yield and yield components is a key aspect of effective selection in crop improvement. Therefore, the objective of this study was: to identify Adaptable bread wheat variety/ies with high level of grain yield and yield stability across locations. The study used 16 bread wheat released varieties, against local check at Fitche Agricultural Research Center (FiARC) in 2020-2022 cropping season. Ten important agronomic traits data were evaluated. Analysis of variance noticed significant difference, among varieties in both separated and combined analysis of variance. The combined ANOVA and the additive main effects and multiplicative interactions (AMMI) analysis for grain yield across environments exhibited significantly affected by environments, which explained 76.6% of the total variation. The genotype and genotype environmental integration were significant and accounted for 8 and 13.1%, respectively. Principal component (PCA) 1 and 2 accounted for 6.5 and 3.5% of the GEI, respectively, with a total of 10% variation. Generally, Sanete and Dandaa varieties were identified for yielding ability and stability, and recommended for the study area and similar agro-ecologies.

Genome-wide association study reveals distinct genetic associations related to leaf hair density in two lineages of wheat-wild relative Aegilops tauschii

Wild relatives of modern crops represent a promising source of genetic variation that can be mined for adaptations to climate change. Aegilops tauschii, the D-sub-genome progenitor of bread wheat (Triticum aestivum), constitutes a reservoir of genetic diversity for improving bread wheat performance and environmental resilience. Leaf hairiness plays an essential biological role in plant defense against biotic and abiotic stress. We investigated the natural variation in leaf hair density (LHD) among 293 Ae. tauschii accessions. Genome-wide association studies were performed for LHD with 2430 and 3880 DArTseq derived single nucleotide polymorphism (SNP) markers in two lineages of this species, TauL1 and TauL2, respectively. In TauL1, three marker-trait associations (MTAs) were located on chromosome 2D, whereas in TauL2, eight MTAs were identified, two associations were localized on each of the chromosomes 2D, 3D, 5D, and 7D. The markers explained phenotypic variation (R2) from 9 to 13% in TauL1 and 11 to 36% in TauL2. The QTLs identified in chromosomes 2D and 5D might be novel. Our results revealed more rapid and independent evolution of LHD in TauL2 compared to TauL1. The majority of LHD candidate genes identified are associated with biotic and abiotic stress responses. This study highlights the significance of intraspecific diversity of Ae. tauschii to enhance cultivated wheat germplasm.

Genome-wide association mapping of Fusarium crown rot resistance in Aegilops tauschii.

Fusarium crown rot (FCR), caused by various Fusarium species, is a primary fungal disease in most wheat-growing regions worldwide. A. tauschii, the diploid wild progenitor of the D-genome of common wheat, is a reservoir of genetic diversity for improving bread wheat biotic and abiotic resistance/tolerance. A worldwide collection of 286 A. tauschii accessions was used to evaluate FCR resistance. Population structure analysis revealed that 115 belonged to the A. tauschii ssp. strangulata subspecies, and 171 belonged to the A. tauschii ssp. tauschii subspecies. Five accessions with disease index values lower than 20 showed moderate resistance to FCR. These five originated from Afghanistan, China, Iran, Uzbekistan, and Turkey, all belonging to the tauschii subspecies. Genome-wide association mapping using 6,739 single nucleotide polymorphisms (SNPs) revealed that two SNPs on chromosome 2D and four SNPs on chromosome 7D were significantly associated with FCR resistance. Almost all FCR resistance alleles were presented in accessions from the tauschii subspecies, and only 4, 11, and 19 resistance alleles were presented in accessions from the strangulata subspecies. Combining phenotypic correlation analysis and genome-wide association mapping confirmed that FCR resistance loci were independent of flowering time, heading date, and plant height in this association panel. Six genes encoding disease resistance-related proteins were selected as candidates for further validation. The identified resistant A. tauschii accessions will provide robust resistance gene sources for breeding FCR-resistant cultivars. The associated loci/genes will accelerate and improve FCR in breeding programs by deploying marker-assisted selection.

Improving bread wheat yield through modulating an unselected AP2/ERF gene.

Crop breeding heavily relies on natural genetic variation. However, additional new variations are desired to meet the increasing human demand. Inflorescence architecture determines grain number per spike, a major determinant of bread wheat (Triticum aestivum L.) yield. Here, using Brachypodium distachyon as a wheat proxy, we identified DUO-B1, encoding an APETALA2/ethylene response factor (AP2/ERF) transcription factor, regulating spike inflorescence architecture in bread wheat. Mutations of DUO-B1 lead to mild supernumerary spikelets, increased grain number per spike and, importantly, increased yield under field conditions without affecting other major agronomic traits. DUO-B1 suppresses cell division and promotes the expression of BHt/WFZP, whose mutations could lead to branched 'miracle-wheat'. Pan-genome analysis indicated that DUO-B1 has not been utilized in breeding, and holds promise to increase wheat yield further.