Winter Wheat Breeding Lines Research Articles

Genome‐Wide Association Mapping and Genomic Prediction of Septoria nodorum Blotch Resistance in Central European Winter Wheat (Triticum aestivum L.)

ABSTRACTSeptoria nodorum blotch (SNB) is a fungal disease of wheat caused by the necrotrophic fungus Parastagonospora nodorum (Berk.), considered as one of the most devastating fungal diseases affecting winter wheat (Triticum aestivum L.). The complex inheritance of resistance to SNB poses significant challenges to breeding programmes. Improving selection precision and identifying novel resistance QTLs are crucial for enhancing SNB resistance. This study investigated strategies for crop genetic improvement, including genome‐wide association mapping (GWAS) and genomic prediction (GP), within a practical breeding programme. A population of 1500 winter wheat breeding lines was phenotyped for SNB resistance over 5 years across 19 geographical locations under natural infection conditions. Despite highly unbalanced breeder's data, medium to high heritabilities for SNB resistance were achieved. GWAS identified 11 significant marker‐trait associations for SNB resistance across Chromosomes 2A, 2B, 4B, 4D, 5D and 7B. GP fivefold cross‐validation analysis revealed a predictive ability of 0.52 for SNB resistance. The resistant wheat genotypes and SNP markers identified in this study will be valuable assets for future breeding efforts to enhance SNB resistance in wheat.

Predicting superior crosses in winter wheat using genomics: A retrospective study to assess accuracy

AbstractIn plant breeding, selecting cross‐combinations that are more likely to result in superior lines for cultivar development is critical. This step, however, is subjective with decisions being based on available genomic and phenotypic data for prospective parents. Genomic prediction (GP) provides new opportunities to accelerate genetic gain for a target trait by identifying superior crosses through simulation of progeny performance. In this context, this study deployed GP using the phenotype and genotype of potential parents to predict the progeny genetic variance (VG) and means of overall, inferior 10%, and superior 10% (μ, μip, and μsp, respectively). This retrospective experimental design investigated whether the crosses that produced superior soft red winter wheat breeding lines would have been made if progeny simulations had guided crossing decisions of breeding programs. Here, data from historical wheat breeding lines were used to train GP models and predict VG and means for yield, test weight, heading date, and plant height for all combinations of 217 parents. Predicted and observed data for 670 lines derived from biparental crosses were compared to assess the accuracy of progeny simulations, and low‐to‐moderate prediction accuracy was observed for the four traits (0.25–0.52). Of the pedigrees that produced lines that were selected and advanced into later stage nurseries, 76% were predicted to give rise to progeny with above‐average yield. The moderate correlation found between predicted progeny means and observed line per se performance justifies using cross‐combination prediction as a tool to reduce crossing number and focus on segregating populations that harbor future cultivars.

Performance of a durum wheat diversity panel under different management systems

AbstractThirty winter and spring durum wheat varieties and breeding lines were evaluated between 2020 and 2022 under low-input, conventional and organic management. Analysis of variance revealed statistically significant effects for the year, management, genotype and their interactions for heading, lodging, grain yield, grain width and length, test weight and thousand grain weight. In the case of ground cover, the genotype × management and the genotype × management × year interactions were not significant. In 2020 and 2022, the latest heading variety ‘Mv Makaróni’ headed on 20th and 21st of May, respectively, whilst in 2021, due to the rainy and cold spring weather, 73% of the varieties started to head only after this date. Lodging was observed only on the conventional sites in two years. The average yield of the experiment was 5.94 t ha−1. For grain yield ‘Mv Vékadur’ and ‘NS Dur’ in the low-input and conventional trials, and genotypes ‘Sambadur’, ‘NS Žad’ and line MVTD12-23 in the organic trials were found as highly stable and best performing genotypes. Significant positive correlations were found between grain width and grain weight. Early ground coverage was measured in all three managements across two years and resulted in significant positive correlation with grain yield.

A diallel study to detect genetic background variation for FHB resistance in winter wheat

Breeding for resistance to Fusarium head blight (FHB) relies strongly on a limited number of larger-effect resistance QTL that have been mapped and associated with nearby markers. Smaller-effect (background) resistance QTL may also contribute moderate levels of resistance yet are mostly poorly characterized. Overall resistance of a genotype is determined by the combined action of both types of resistance QTL. This study aimed to identify well-adapted, advanced hard red winter (HRW) wheat breeding lines with useful background resistance QTL. A diallel trial consisting of 11 parents and 55 non-reciprocal F1 hybrids was tested for Type II FHB resistance in a replicated greenhouse experiment. Significant differences were detected among entries for disease severity (DS), general combining ability (GCA) and specific combining ability (SCA) with four parents being identified as the best general combiners with lowest DS. The ratio of GCA:SCA effects suggested that additive QTL effects were of primary importance. Overall, resistance QTL showed incomplete dominance, an excess of dominant alleles, and a greater contribution of positive effect genes. F2 of the six best F1 hybrids with the lowest DS were compared in a second greenhouse FHB trial to select possible transgressive segregates for continued evaluation and line development.

Differentiation of Triticum aestivum L. genotypes according to combination of yield and flour quality indicators

Purpose. Hence, the purpose of this study was to identify winter bread wheat (Triticum aestivum L.) cultivars and breeding lines giving high yields, with improved flour quality and with combination of these features.
 Materials and Methods. The study was conducted at the V.M. Remeslo Myronivka Institute of Wheat (MIW) of NAAS of Ukraine in 2019/20–2021/22. Ten new winter bread wheat cultivars and four promising breeding lines were evaluated. Winter wheat was grown in accordance with routine techniques in the Forest-Steppe of Ukraine. The yields were harvested and recorded in accordance with methods of qualification examination of plant varieties for suitability for dissemination in Ukraine. Winter bread wheat grain quality parameters were determined by conventional methods at the Grain Quality Laboratory MIW.
 Results and Discussion. There was a significant variability of yield and flour quality parameters depending on the conditions of the study years. On average across the winter bread wheat cultivars and breeding lines, the highest contents of protein (14.7%) and wet gluten content (31.9%) were recorded in 2019/20, but the lowest yield (3.40 t/ha) was harvested that year. In 2020/21, on the contrary, the yield was higher (6.46 t/ha), while the sedimentation value (59 mL), protein content (11.9%), and wet gluten content (27.4%) were lower. Cv. ‘MIP Aelita’, ‘MIP Vidznaka’ and breeding line ‘Lutescens 37548’ yielded significantly more than the check cultivar (‘Podolianka’; 5.05 t/ha; LSD05 = 0.33 t/ha). We singled out genotypes that on average in 2019/20–2021/22 were significantly superior to the check cultivar (‘Podolianka’) in term of protein content (‘MIP Nika’, ‘MIP Vidznaka’, ‘MIP Dovira’, ‘Lutescens 37548’, ‘Lutescens 60049’, and ‘Lutescens 60400’), sedimentation value (‘MIP Feieriia’, ‘Lutescens 37548’, ‘Lutescens 60049’, and ‘Lutescens 60302’) and wet gluten content (‘Lutescens 375480’). It should be noted that breeding line ‘Lutescens 37548’ significantly outperformed the check cultivar in all measured flour quality parameters. Based on combinations of high yield with several parameters of flour quality, cv. ‘MIP Aelita’ and ‘MIP Vidznaka’ and breeding lines ‘Lutescens 37548’, ‘Lutescens 60049’, and ‘Lutescens 60302’ were distinguished.
 Conclusions. The selected winter bread wheat cultivars and breeding lines can be used in breeding to create starting materials as sources of improved corresponding parameters of flour quality, a set of the investigated characteristics of flour quality and of combinations of high yield and good parameters of flour quality.

Development and validation of diagnostic markers for the reduced height gene Rht8 in wheat

AbstractWheat (Triticum aestivum L.) production is necessary for global food and nutrition security. Reducing plant height is an effective strategy to increase lodging resistance, harvest index, and eventually wheat yield. Rht8 is a gibberellic acid–sensitive reduced height (Rht) gene and has been cloned. Rht8 encodes a ribonuclease H‐like (RNHL) superfamily protein that reduces plant height without reduction in coleoptile length. High‐throughput diagnostic markers are not available for precise selection of RNHL in wheat breeding. In this study, we found that different cultivars may carry 1–3 copies of RNHLs on chromosome 2D, and only 2D carries the semi‐dwarf allele of RNHL although the wild‐type RNHL allele is detected in several other chromosomes. We developed two kompetitive allele specific PCR (KASP) markers, Rht8‐KASP‐V2 and Rht8‐KASP‐V3, based on the causal variation in RNHL. The two markers co‐segregated with plant height in a recombinant inbred population and were validated in a panel of hard winter wheat breeding lines from the 2022 Regional Germplasm Observation Nursery and Regional Performance Nursery. Rht8 has not been extensively deployed in US hard winter wheat and development of the diagnostic KASP markers will facilitate Rht8 transfer to US wheat cultivars.

Exploring GWAS and genomic prediction to improve Septoria tritici blotch resistance in wheat

Septoria tritici blotch (STB) is a destructive foliar diseases threatening wheat grain yield. Wheat breeding for STB disease resistance has been identified as the most sustainable and environment-friendly approach. In this work, a panel of 316 winter wheat breeding lines from a commercial breeding program were evaluated for STB resistance at the seedling stage under controlled conditions followed by genome-wide association study (GWAS) and genomic prediction (GP). The study revealed a significant genotypic variation for STB seedling resistance, while disease severity scores exhibited a normal frequency distribution. Moreover, we calculated a broad-sense heritability of 0.62 for the trait. Nine single- and multi-locus GWAS models identified 24 marker-trait associations grouped into 20 quantitative trait loci (QTLs) for STB seedling-stage resistance. The seven QTLs located on chromosomes 1B, 2A, 2B, 5B (two), 7A, and 7D are reported for the first time and could potentially be novel. The GP cross-validation analysis in the RR-BLUP model estimated the genomic-estimated breeding values (GEBVs) of STB resistance with a prediction accuracy of 0.49. Meanwhile, the GWAS assisted wRR-BLUP model improved the accuracy to 0.58. The identified QTLs can be used for marker-assisted backcrossing against STB in winter wheat. Moreover, the higher prediction accuracy recorded from the GWAS-assisted GP analysis implies its power to successfully select superior candidate lines based on their GEBVs for STB resistance.

Seedling and adult plant resistance to leaf rust in some Bulgarian common wheat lines.

The response of 250 common winter wheat breeding lines was investigated for resistance to the causative agent of Puccinia triticina under conditions of an infected field on the territory of Dobrudzha Agricultural Institute - General Toshevo, Bulgaria, during three successive seasons. Twenty lines with different degrees of resistance under field conditions were selected. Multi-pathotype testing was used to study the response of these lines at seedling stage under greenhouse conditions to individual pathotypes of P. triticina. Based on the response of the lines at seedling and adult stages, we found out that 20 % of them carried race-specific resistance. One of the lines (99/08-52) reacted with full resistance to the pathotypes used under greenhouse conditions. The reaction demonstrated by this line coincided with the response of isogenic lines carrying the genes Lr9, Lr19, Lr22a, Lr22b and Lr25. The other three lines (19/06- 108, 82/08-43 and 82/08-35) showed a resistant reaction to 6 or 5 of the pathotypes used in the study. Their response partially coincided with the reaction of 5 isogenic lines, and the presence of some of these genes in the above lines is quite possible. Lines carrying this type of resistance are to be subjected to further genetic and breeding investigations to prove the presence of a race-specific gene. Twenty-five percent of the lines combined partial race-specific resistance at seedling stage with the resistance of race non-specific nature at adult stage. Forty percent of all studied lines carried race non-specific resistance, and 15 % of the lines possessed resistance of the "slow rusting" type. As a result of the study we carried out, the lines that demonstrated stable resistance to leaf rust can provide sufficient protection of the host and can be included in the breeding programs for developing varieties resistant to P. triticina.

Eyespot resistance of winter wheat breeding lines evaluated with marker-assisted selection and inoculation tests at the seedling and adult plant stages

Eyespot resistance of winter wheat breeding lines evaluated with marker-assisted selection and inoculation tests at the seedling and adult plant stages

Influence of agroclimatic conditions of the spring-summer vegetation on the formation of winter wheat yield under the needs of the forest-steppe of Western Siberia

Air temperature and moisture availability are the main environmental factors that have a significant impact on the development of plants during the growing season. The aim of this study is to study the relationship of yield and its constituent elements with climatic factors and to show their role in the formation of productivity of winter wheat. The research was carried out in 2009-2022 in the fields of the Siberian Research Institute of Plant Growing and Breeding, a branch of the Institute of Cytology and Genetics of the Siberian Branch of the Russian Academy of Sciences. The research material was varieties and breeding lines of winter soft wheat of competitive variety testing. A positive dependence of the amount of precipitation and the hydrothermal coefficient in the interphase period “resumption of vegetation - trumpeting” with the duration of the growing season (r = 0.78; r = 0.73), productive tillering (r = 0.59; r = 0.64) was revealed, plant height (r = 0.60; r = 0.58), number of grains per plant (r = 0.66; r = 0.67). The correlation coefficient of productivity with the HTC and the amount of precipitation was r = 0.66 and r = 0.67, respectively, in the period of “booting - earing”. There is a significant negative correlation of resistance to lodging with both HTC and precipitation (r = -0.63; r = -0.56). The correlation coefficient of the HTC and the amount of rainfall with resistance to lodging in the interphase period “heading - wax ripeness” was significant (r = 0.55). HTC in the period “heading - wax ripeness” was directly proportional to the grain size index r = 0.60 and the amount of precipitation with a mass of 1000 grains r = 0.58. For the entire period of spring-summer vegetation, the correlation coefficient of the HTC and the amount of rainfall with the duration of the growing season was r = 0.63 and r = 0.65, respectively, with a height of r = 0.71 and r = 0.72, resistance to lodging r = -0.68 and r = -0.64 and overall bakery score r = -0.62 and r = -0.63. The amount of precipitation throughout the entire spring-summer vegetation has a positive effect on the grain weight per plant (r = 0.57). The sum of effective temperatures has a positive relationship with the nature of the grain in the period of “booting - heading” (r = 0.65). The correlation coefficient of the sum of effective temperatures with the amount of gluten in the period “heading - wax ripeness” r = 0.74 for the entire spring-summer vegetation r = 0.67.

Genetic Basis of Resistance to Warrior (-) Yellow Rust Race at the Seedling Stage in Current Central and Northern European Winter Wheat Germplasm.

To evaluate genetic variability and seedling plant response to a dominating Warrior (-) race of yellow rust in Northern and Central European germplasm, we used a population of 229 winter wheat cultivars and breeding lines for a genome-wide association study (GWAS). A wide variation in yellow rust disease severity (based on infection types 1-9) was observed in this panel. Four breeding lines, TS049 (from Austria), TS111, TS185, and TS229 (from Germany), and one cultivar, TS158 (KWS Talent), from Germany were found to be resistant to Warrior (-) FS 53/20 and Warrior (-) G 23/19. The GWAS identified five significant SNPs associated with yellow rust on chromosomes 1B, 2A, 5B, and 7A for Warrior (-) FS 53/20, while one SNP on chromosome 5B was associated with disease for Warrior (-) G 23/19. For Warrior (-) FS 53/20, we discovered a new QTL for yellow rust resistance associated with the marker Kukri_c5357_323 on chromosome 1B. The resistant alleles G and T at the marker loci Kukri_c5357_323 on chromosome 1B and Excalibur_c17489_804 on chromosome 5B showed the largest effects (1.21 and 0.81, respectively) on the severity of Warrior (-) FS 53/20 and Warrior (-) G 23/19. Our results provide the basis for knowledge-based resistance breeding in the face of the enormous impact of the Warrior (-) race on wheat production in Europe.

Variability of yield components in winter wheat varieties and breeding lines under environment of Ukrainian Forest-Steppe

Topicality. The main task of winter wheat breeding is to increase productivity, therefore, the development and introduction of new varieties of winter wheat with high productivity potential being well adapted to changing growing conditions into agricultural production is an urgent area of research. Breeders' efforts are aimed at developing varieties with a successful combination of high parameters of all the main productivity elements in one genotype, which will maximise grain yield. Breeding work is determined by many factors, among which the search and development of new genetic sources with high performance indicators. Therefore, the peculiarities of yield potential realization and the study of the mechanisms of productivity element formation under changing meteorological conditions are important for establishing the response rate and selecting the most stable productive genotypes and their further involvement in breeding programs. Purpose. To identify the best varieties and breeding lines of winter wheat in terms of productivity elements in the environment of the Forest-Steppe of Ukraine for their involvement in crossbreeding programmes. Methods. Visual – phenological observations; laboratory-field – determination of biometric indicators; mathematical and statistical – establishing the reliability of the obtained data. Results. It was found that the maximum realisation of the yield potential of winter wheat plants by structural elements occurred under optimal growing conditions such as in years with higher moisture availability and sowing on 5 October. Yield formation was significantly influenced by the weather conditions of the year, genotype and unaccounted factors. Sowing dates had a significant effect only on the manifestation of the plant height trait. There was a minor variation (3.8 %÷5.5 %) in plant height in all varieties and breeding lines. Different levels of variability were found for the following traits: number of productive stems varied from Cv=16.4 % (second sowing date in the dry 2019/20) to Cv=27.6 % (first sowing date in the favourable 2020/21); main head grain content and thousand grain weight – Cv=10.7÷17.6 % and Cv=8.8÷16.9 %, respectively. Regardless of varietal characteristics, the main spike length had insignificant (Сv=5.6÷8.8 %) phenotypic variability with a range of variation of 0.2–2.0 cm. There were determined the variability levels of traits by the spikelet number per spike (Сv=5.7 %÷8.6 %), by grain weight per spike (Сv=13.1÷20.5 %) and per plant (Сv=20.5÷36.3 %). Conclusions. The varieties MIP Assol, Hratsiia MYR, MIP Dniprianka, MIP Yuvileina and breeding lines LUT 55198, LUT 37519 consistently formed a high level of productivity elements regardless of sowing dates and conditions of the growing year, which indicates their high adaptive capacity. They are recommended for breeding programmes as valuable parental components. Key words: productivity parameters, trait, variation, sowing date, year conditions

Climate change may outpace current wheat breeding yield improvements in North America

Variety adaptation to future climate for wheat is important but lacks comprehensive understanding. Here, we evaluate genetic advancement under current and future climate using a dataset of wheat breeding nurseries in North America during 1960-2018. Results show that yields declined by 3.6% per 1 °C warming for advanced winter wheat breeding lines, compared with −5.5% for the check variety, indicating a superior climate-resilience. However, advanced spring wheat breeding lines showed a 7.5% yield reduction per 1 °C warming, which is more sensitive than a 7.1% reduction for the check variety, indicating climate resilience is not improved and may even decline for spring wheat. Under future climate of SSP scenarios, yields of winter and spring wheat exhibit declining trends even with advanced breeding lines, suggesting future climate warming could outpace the yield gains from current breeding progress. Our study highlights that the adaptation progress following the current wheat breeding strategies is challenging.

Genome-wide association study and genomic prediction of resistance to stripe rust in current Central and Northern European winter wheat germplasm

Key messageWe found two loci on chromosomes 2BS and 6AL that significantly contribute to stripe rust resistance in current European winter wheat germplasm.Stripe or yellow rust, caused by the fungus Puccinia striiformis Westend f. sp. tritici, is one of the most destructive wheat diseases. Sustainable management of wheat stripe rust can be achieved through the deployment of rust resistant cultivars. To detect effective resistance loci for use in breeding programs, an association mapping panel of 230 winter wheat cultivars and breeding lines from Northern and Central Europe was employed. Genotyping with the Illumina® iSelect® 25 K Infinium® single nucleotide polymorphism (SNP) genotyping array yielded 8812 polymorphic markers. Structure analysis revealed two subpopulations with 92 Austrian breeding lines and cultivars, which were separated from the other 138 genotypes from Germany, Norway, Sweden, Denmark, Poland, and Switzerland. Genome-wide association study for adult plant stripe rust resistance identified 12 SNP markers on six wheat chromosomes which showed consistent effects over several testing environments. Among these, two marker loci on chromosomes 2BS (RAC875_c1226_652) and 6AL (Tdurum_contig29607_413) were highly predictive in three independent validation populations of 1065, 1001, and 175 breeding lines. Lines with the resistant haplotype at both loci were nearly free of stipe rust symptoms. By using mixed linear models with those markers as fixed effects, we could increase predictive ability in the three populations by 0.13–0.46 compared to a standard genomic best linear unbiased prediction approach. The obtained results facilitate an efficient selection for stripe rust resistance against the current pathogen population in the Northern and Central European winter wheat gene pool.

Remote spectral analysis of varieties and lines of winter wheat during the flowering period

Purpose. Conduct a spectral assessment of winter wheat varieties (‘MIP Assol’, ‘Balada Myronivska’, ‘Hratsiia Myronivska’, ‘MIP Yuvileina’, ‘MIP Lada’, ‘MIP Dniprianka’, and standard ‘Podolianka’) and perspective breeding lines (‘Erythrospermum 55023’, ‘Lutescens 22198’, ‘Lutescens 37519’, ‘Lutescens 60049’, ‘Lutescens 60107’) of Myronivka Institute breeding during the flowering period and to evaluate the dependence of the obtained NDVI indicator on their productivity. Methods. The research was conducted during the 2018/19–2020/21 growing seasons in the breeding crop rotation of the winter wheat breeding laboratory of the V. M. Remeslo Myronivka Wheat Institute of the National Academy of Sciences of Ukraine. The main method of research is field, supplemented by analytical studies, measurements, calculations and observations. Obtaining values of vegetation indices of varieties and breeding lines of winter wheat was carried out using the Mavic zoom 2 UAV (unmanned aerial vehicle) using the Parrot Sequoia multispectral camera. Pix4Dcapture and Pix4Dmapper programs were used to create an orthophoto map. Photographing was carried out with a multispectral camera at a height of 30 m above the level of the object under study in order to improve the quality of the orthophoto map with an overlap of 80% of the images and a time interval of 2 seconds. The NDVI index (normalized difference vegetation index) was calculated according to the appropriate formula. Results. According to the research results, regardless of the conditions of the year, in the first, optimal sowing period (25.09–05.10), the NDVI indicator in the flowering-ripening phase of wheat had higher values than in the second, late period (05–15.10) (average value over three years for the first semester was 0.69, the second – 0.62). In the course of the research, we established the dependence of the vegetation index NDVI on the level of productivity of wheat genotypes. The best varieties and promising lines among those studied were ‘MIP Lada’, ‘Lutescens 55198’ and ‘Lutescens 60049’, as well as ‘MIP Assol’ and ‘Hratsiia Myronivska’, which were less sensitive to sowing dates and had a higher index and control of yield indicators even with late sowing dates. Conclusions. Although existing today phenotyping methods need to be improved and localized, in the near future they will become an indispensable tool for the breeder, which will increase the volume of studied varieties and improve the quality of the results of morpho-biological analysis

EVALUATION OF YIELD AND ADAPTABILITY OF BREEDING LINES OF WINTER SOFT WHEAT IN THE FOREST-STEPPE OF THE MIDDLE VOLGA REGION

Nowadays, breeding for productivity and ecological adaptability are the main directions in breeding of varieties of various agricultural crops. Evaluation of selectable genotypes according to the parameters of ecological adaptability allows to establish the most favorable zones and select suitable technologies for their cultivation. The purpose of the research was to evaluate breeding lines of winter soft wheat by productivity and ecological adaptability in the conditions of the forest-steppe of the Middle Volga region. The material for the research was 10 breeding lines of winter soft wheat of various crossing combinations, the study took place in 2018-2021 as study in competitive and preliminary variety tests. It was found that high yields were observed in breeding lines number 6 (on average for the entire period of research of 4.89 t/ha) and number 32 (5.01 t/ha), which is significantly higher than the yield of Fotinya standard (4.20 t/ha , HCP05 = 0.67 t/ha). Consistently high coefficients of adaptability at the level of 1.0 and above (0.95-1.24) had 4 breeding lines - numbers 6, 7, 10 and 32 in all years of variety testing of winter soft wheat. For cultivation under intensive conditions, breeding lines of winter soft wheat number 6 and 32 are of the greatest value, in semi-intensive - lines number 7, 25 and 62, extensive - lines number 10, 13 and 17. Comprehensive assessment in the breeding process of yield, adaptability of genotypes, including ecological plasticity, contributes to more efficient production usage of the created varieties.

Impact of Combined Drought and Heat Stress and Nitrogen on Winter Wheat Productivity and End-Use Quality

Water deficit and heat stress are the main abiotic stresses affecting the yield and quality of winter wheat. The increasing frequency of the simultaneous occurrence of these two stresses might threaten global food security and drives the need to breed resilient high-quality cultivars. The aim of this study was to evaluate the grain yield, quality and gluten protein characteristics in 50 winter wheat cultivars and breeding lines during the harvest years of 2018 and 2019. The yield and grain quality components were affected more severely by the combined heat and drought in 2019 than the drought in 2018. Two nitrogen (N) fertilization regimes were studied, sustainable (S, 15/100/30 kg N ha−1) and high-input (HI, 15/100/100 kg N ha−1). The yield was higher in HI trials compared to S trials by 2.2 t ha−1 in 2018 and by 2.4 t ha−1 in 2019. Higher protein content and sedimentation volume and lower yield, test weight and starch content were observed under combined heat and drought stress in 2019 compared to 2018. Genotypes containing the Glu-D1 x5-y10 allele exhibited the higher amounts of unextractable polymeric proteins (%UPP = 58.5%) in gluten studied by size exclusion liquid chromatography (SE-HPLC) as compared to Glu-D1 x2-y12 allele (%UPP = 54.3%). Genotype was the main determinant of gluten protein characteristics regardless of the nitrogen application and the abiotic stress conditions. The results suggest that the relatively mild drought and heat events in Lithuania might not threaten gluten quality in the future; however, breeding efforts should be directed towards improved drought and heat stress resistance to ensure stable wheat productivity in the region.

Genetic architecture of end-use quality traits in soft white winter wheat

BackgroundGenetic improvement of end-use quality is an important objective in wheat breeding programs to meet the requirements of grain markets, millers, and bakers. However, end-use quality phenotyping is expensive and laborious thus, testing is often delayed until advanced generations. To better understand the underlying genetic architecture of end-use quality traits, we investigated the phenotypic and genotypic structure of 14 end-use quality traits in 672 advanced soft white winter wheat breeding lines and cultivars adapted to the Pacific Northwest region of the United States.ResultsThis collection of germplasm had continuous distributions for the 14 end-use quality traits with industrially significant differences for all traits. The breeding lines and cultivars were genotyped using genotyping-by-sequencing and 40,518 SNP markers were used for association mapping (GWAS). The GWAS identified 178 marker-trait associations (MTAs) distributed across all wheat chromosomes. A total of 40 MTAs were positioned within genomic regions of previously discovered end-use quality genes/QTL. Among the identified MTAs, 12 markers had large effects and thus could be considered in the larger scheme of selecting and fixing favorable alleles in breeding for end-use quality in soft white wheat germplasm. We also identified 15 loci (two of them with large effects) that can be used for simultaneous breeding of more than a single end-use quality trait. The results highlight the complex nature of the genetic architecture of end-use quality, and the challenges of simultaneously selecting favorable genotypes for a large number of traits. This study also illustrates that some end-use quality traits were mainly controlled by a larger number of small-effect loci and may be more amenable to alternate selection strategies such as genomic selection.ConclusionsIn conclusion, a breeder may be faced with the dilemma of balancing genotypic selection in early generation(s) versus costly phenotyping later on.

Evaluation of yield and parameters of ecological adaptability of breeding lines of winter soft wheat in the forest-steppe of the Middle Volga region

The article presents the results of a study of breeding lines of winter soft wheat in terms of yield and various parameters of ecological adaptability. It has been established that the high adaptive properties of winter soft wheat genotypes are not combined with high yields. Breeding lines of winter soft wheat with a compromise between yield and ecological adaptability have been identified. A comprehensive assessment of the yield and parameters of ecological adaptability of genotypes in the breeding process of winter soft wheat contributes to greater agroecological stability of the created varieties.

Genetic Incorporation of the Favorable Alleles for Three Genes Associated With Spikelet Development in Wheat.

The number of spikelets per spike is an important trait that directly affects grain yield in wheat. Three quantitative trait loci (QTLs) associated with spikelet nodes per spike (SNS) were mapped in a population of recombinant inbred lines generated from a cross between two advanced breeding lines of winter wheat based on the phenotypic variation evaluated over six locations/years. Two of the three QTLs are QSns.sxau-2A at the WHEATFRIZZY PANICLE (WFZP) loci and QSns.sxau-7A at the WHEAT ORTHOLOG OF APO1 (WAPO1) loci. The WFZP-A1b allele with a 14-bp deletion at QSns.sxau-2A was associated with increased spikelets per spike. WAPO-A1e, as a novel allele at WAPO1, were regulated at the transcript level that was associated with the SNS trait. The third SNS QTL, QSns.sxau-7D on chromosome 7D, was not associated with homoeologous WAPO-D1 or any other genes known to regulate SNS. The favorable alleles for each of WZFP-A1, WAPO-A1, and QSns.sxau-7D are identified and incorporated to increase up to 3.4 spikelets per spike in the RIL lines. Molecular markers for the alleles were developed. This study has advanced our understanding of the genetic basis of natural variation in spikelet development in wheat.