Hybrid Wheat Research Articles

Unlocking big data doubled the accuracy in predicting the grain yield in hybrid wheat.

The potential of big data to support businesses has been demonstrated in financial services, manufacturing, and telecommunications. Here, we report on efforts to enter a new data era in plant breeding by collecting genomic and phenotypic information from 12,858 wheat genotypes representing 6575 single-cross hybrids and 6283 inbred lines that were evaluated in six experimental series for yield in field trials encompassing ~125,000 plots. Integrating data resulted in twofold higher prediction ability compared with cases in which hybrid performance was predicted across individual experimental series. Our results suggest that combining data across breeding programs is a particularly appropriate strategy to exploit the potential of big data for predictive plant breeding. This paradigm shift can contribute to increasing yield and resilience, which is needed to feed the growing world population.

Comprehensive Selection Criteria for High-Yielding Bread Wheat (Triticum aestivum L.) Hybrids under Salinity Stress

THE MOST important aspect of this investigation was evaluating a set of wheat genotypes with different responses to salt stress while conducting the selection process on the number of spikes/plant, the number of filled grains/spike, 1000-grain weight, and grain yield/plant traits besides, some physiological attributes and related to salinity tolerance such as Na+, K+ contents, Na+/K+ ratio, osmotic adjustment, proline, and glycine betaine contents under control and salinity conditions. The wheat genotypes were divided into two groups according to half diallel analysis. Where, the first one included parents, namely; Sakha 8, Shandweel 1, Masr 1, Giza 171, Sakha 94, Gimeaza 11, and Gimeaza 12, respectively. While the second group was 21 F1 wheat crosses obtained from half diallel crossing among the seven wheat genotypes. Heterosis over better-parent, general, and specific combining ability effects was the most important measurements for all studied traits for both experiments. Further, the seven wheat genotypes and the highest 5 F1 crosses were evaluated for the salinity tolerance indices test using grain yield/plant trait depending on all data estimated for all studied attributes under salt-stress treatment compared to the control experiment. The final results revealed that; parents 1, 2, and 3 besides, the crosses; P1 X P2, P1 X P3, P2 X P3, P2 X P4, and P3 X P4 exhibited a high trend in salinity tolerance under salinity stress treatment compared to the control experiment. Further, the previous wheat genotypes recorded high levels of salinity tolerance indices. SCoT markers determined the hybrids with the highest salinity tolerance indices. Out of nine primers used, only six generated polymorphic bands with 43 polymorphic bands. Therefore, identifying genetic evidence at the molecular level could be used in the future as a taxonomic tool to tolerate salinity in promising wheat genotypes.

Genome-Wide Association and Prediction of Male and Female Floral Hybrid Potential Traits in Elite Spring Bread Wheat Genotypes.

Hybrid wheat breeding is one of the most promising technologies for further sustainable yield increases. However, the cleistogamous nature of wheat displays a major bottleneck for a successful hybrid breeding program. Thus, an optimized breeding strategy by developing appropriate parental lines with favorable floral trait combinations is the best way to enhance the outcrossing ability. This study, therefore, aimed to dissect the genetic basis of various floral traits using genome-wide association study (GWAS) and to assess the potential of genome-wide prediction (GP) for anther extrusion (AE), visual anther extrusion (VAE), pollen mass (PM), pollen shedding (PSH), pollen viability (PV), anther length (AL), openness of the flower (OPF), duration of floret opening (DFO) and stigma length. To this end, we employed 196 ICARDA spring bread wheat lines evaluated for three years and genotyped with 10,477 polymorphic SNP. In total, 70 significant markers were identified associated to the various assessed traits at FDR ≤ 0.05 contributing a minor to large proportion of the phenotypic variance (8–26.9%), affecting the traits either positively or negatively. GWAS revealed multi-marker-based associations among AE, VAE, PM, OPF and DFO, most likely linked markers, suggesting a potential genomic region controlling the genetic association of these complex traits. Of these markers, Kukri_rep_c103359_233 and wsnp_Ex_rep_c107911_91350930 deserve particular attention. The consistently significant markers with large effect could be useful for marker-assisted selection. Genomic selection revealed medium to high prediction accuracy ranging between 52% and 92% for the assessed traits with the least and maximum value observed for stigma length and visual anther extrusion, respectively. This indicates the feasibility to implement genomic selection to predict the performance of hybrid floral traits with high reliability.

Preparation of wheat bran-titanium dioxide (TiO2) composite and its application for selenium adsorption

Selenium is metabolically required by a variety of organisms, but it may induce toxicity at high doses. The removal of a high concentration of selenium from water with natural and biocompatible materials is a vital component in the reuse of selenium given that the process converts low-cost materials into value-added products. In this study, novel wheat bran-titanium dioxide (TiO2) composite was prepared through the in situ hydrolysis of titanium oxysulfate in the presence of wheat bran after destarching, and its sorption characteristics toward Se(IV) from aqueous solutions were investigated. Scanning electronic microscopy and X-ray diffraction results revealed that amorphous TiO2 particles dispersed in the fiber matrix and on the fiber surface. The sorption of Se(IV) on the wheat bran-TiO2 composite was fast and pH dependent. The wheat bran-TiO2 composite exhibited high sorption capacity for Se(IV) at high temperatures, and the Langmuir isotherm models were able to fit the experimental data. The presence of phosphate reduced the efficiency of Se(IV) adsorption, whereas other coexisting anions had slight effects on Se(IV) adsorption. Fourier transform infrared analysis showed that the hydroxyl groups of TiO2 on the composite surface were involved in Se(IV) adsorption. The hybrid wheat bran-TiO2 composite has a promising application for Se(IV) sorption and enrichment in aqueous solutions.

Introgressive Hybridization of Common Wheat: Results and Prospects

This review is devoted to the introgressive hybridization of common wheat, the process of integrating the genes of other cultivated or wild species from the secondary and tertiary gene pools into its genome in order to increase the genetic diversity of this most important agricultural crop. The results achieved in the introgressive hybridization of common wheat over the past 20 years are summarized, the distribution of alien translocations by subgenomes and chromosomes of common wheat is analyzed, and the possibilities for further development of this direction of research and selection based on the use of alien genetic material are discussed.

Chromosome Stability of Synthetic-Natural Wheat Hybrids.

Primary allopolyploids are not only ideal materials to study species evolution, but also important bridges in incorporating genetic diversity of wild species into crops. Primary allopolyploids typically exhibit chromosome instability that a disadvantage trait in crop breeding. Newly synthesized hexaploid wheat has been widely used in wheat genetics and breeding studies. To better understand the cytological and genetic basis of chromosome instability, this study investigated the chromosomes of a large number of seeds derived from the synthetic wheat SHW-L1 and its hybrids with natural wheat. SHW-L1 exhibited persistent chromosome instability since we observed a high frequent chromosome variation de novo generated from euploid SHW-L1 plants at the 14th generation of selfing (F14). High frequent chromosome variations were also observed in the F2 hybrids and most of the analyzed recombinant inbred lines (RILs) at F14, derived from the cross of SHW-L1 with common wheat variety Chuanmai 32. Chromosome instability was associated with frequent univalency during meiotic metaphase I. The experiment on reciprocal crosses between SHW-L1 and Chuanmai 32 indicated that cytoplasm has not obvious effects on chromosome instability. An analysis on 48 F14 RILs revealed chromosome variation frequency was not associated with the Ph1 alleles from either SHW-L1 or Chuanmai 32, rejecting the hypothesis that chromosome instability was due to the Ph1 role of synthetic wheat. In the analyzed RILs, chromosome instability influences the phenotype uniformity, showing as obvious trait differences among plants within a RIL. However, the analyzed commercial varieties only containing ∼12.5% genomic components of synthetic wheat were chromosomally stable, indicating that chromosome instability caused by synthetic wheat can be effectively overcome by increasing the genetic background of common wheat.

Spikelet movements, anther extrusion and pollen production in wheat cultivars with contrasting tendencies to cleistogamy

BackgroundCleistogamic flowers are a main barrier in pollen dispersal for cross-pollination necessary in wheat hybrid breeding. The aim of our study was to gain new knowledge on the biology of wheat flowering, in particular on the differences between the cleisto- and chasmogamic forms which has certainly cognitive significance, but it can also be used in practice when seeking a female and male ideotypes for cross hybridization.ResultsWe characterized the most significant features defining the flowering specificity in two wheat cultivars with contrasting tendency to cleistogamy: Piko (chasmogamous) and Dacanto (cleistogamous). In the field observations we assessed diurnal pattern of anther extrusion and anther extrusion capacity. For the first time we adapted the time lapse method for measuring kinetics of the spikelet movement and 3-D image correlation technique for the non-invasive measurements of potential deformations of the spikelet lemmas. We found that the two cultivars differ in the potential of pollen dispersion for-cross-pollination and in the spikelet kinetics. We also described some anatomical traits that can have potential functional role in floret opening. None of the cultivars showed any symptoms of lemma surface deformation.ConclusionsThe cleistogamic and chasmogamic wheat cultivars differ significantly in the potential for pollen dispersion for cross-pollination, which is mainly related to anther extrusion capacity. Although none of these features differentiated the cultivars clearly, we assume, based on spikelet kinetics and the lack of lemmas surface deformation, that the water transport and turgor of cells is essential for the floret opening and anther extrusion in wheat. The search for parental ideotype should be supported by marker assisted selection, e.g. based of polymorphisms in genes related to aquaporin biosynthesis.

Heredity of leaf apparatus features in F2 of soft winter wheat

The aim of the research was to study the heredity nature of flag (first top) and sub-flag (second top) leaves of F2 hybrid populations obtained from the crossbred varieties and lines of soft winter wheat of different morphophysiological types. The research was conducted in the experimental field of KhNAU named after V.V. Dokuchaiev in 2015 – 2016. The vegetation period of 2015 – 2016 turned out to be abnormally warm with a lot of precipitation. The amount of precipitation during the wheat vegetation period in 2015 – 2016 was 597,8 mm, which was significantly higher than the long-term average (456,0 mm). Such weather conditions affected the course of vernalization and wintering of plants, contributed to the development of diseases and pests, complicated and stretched the harvest period, its quantity and quality. 14 F2 hybrid populations, obtained by crossbreeding 16 varieties and lines were used as a starting material. The selection of the parent pairs was performed on a set of the morphological and anatomical productivity features. Based on cluster analysis (K-average method), the set of the studied genotypes of soft winter wheat was divided into four clusters. The genotypes of the first cluster had a high level of ear productivity and the maximum level of development of the anatomical structure features of the stem and ear. The genotypes of the second and third clusters are two “opposite” types of variability of the productivity features, leaf apparatus and anatomical structure of the stem and ear. Thus, the genotypes of the second cluster are characterized by a relatively high level of development of the features of ear productivity, but minimal – the features of anatomical structure, and for the third vice versa. The genotypes of the third cluster can be a donor of the anatomical structure features, and the second – ear productivity. The genotypes of the fourth cluster had the maximum level of development of the group of the features of the leaf apparatus, productivity and a fairly high level of the development of the anatomical structure features. The varieties from the first cluster were used for crossing: Smuhlianka, Izolda, Prestizh, Kharkivska 105; from the second one: Odeska 267, Venera, Ebi, Statna, Dobirna, KIU line – 7; from the third one: KIU lines – 40, L 80 – III / 7, Patriot variety; from the fourth one: Pereiaslavka, Lehenda, line L 89 – I/2. The hybrids were sown in a block with the parental forms, the area of the plot for the parental forms made up 1 m2, the area of the hybrid populations plots depended on the number of seeds and was equal to 1 – 2 m2. The level of heredity according to the characteristics of the leaf apparatus of F2 hybrids of soft winter wheat was determined, namely the frequency (Tf) and the degree of transgressions (Td) and the heredity coefficient in the “broad sense”. The frequency of transgressions of the hybrids on the basis of the area of the flag leaf varied from 3,00% to 40,00%, and the degree of transgressions varied from 3,30% to 52,90%, but in three combinations the transgression was zero. The heredity coefficient in the “broad sense” ranged from 0,07 to 0,99. According to the total area of the two upper leaves (flag and sub-flag), the frequency of transgressions varied from 6,70% to 50,00%, and the degree of transgressions – from 3,60% to 45,20%. In two combinations, the transgression was zero. High and medium heredity coefficients, exceeding 0,50, and a high manifestation of transgressions were observed in the combinations: KIU-7 / Smuhlianka (Tf – 33,3 and Td – 45,2%), Kharkivska 105 / Smuhlianka (Tf – 30,00 and Td – 45,23%) Izolda / Prestige (Tf – 30,00 and Td– 12,60%), Ebi / L 89 – I / 2 (Tf – 23,30 and Td – 31,50%). These combinations can predict the effective plant selection, starting with F2 and F3. Key words: soft winter wheat, F2 hybrids, heredity coefficient in the “broad sense”, frequency and degree of transgression.

Interspecific crosses involving Rf3 gene carriers as potential sources of R lines for D2 type cytoplasm based hybrid wheat system

The exploitation of heterosis, which is associated with the development of hybrid wheat varieties, has a great potential for increasing global wheat grain yields. Nevertheless, common wheat hybrids now account for less than 1% of global wheat production. In practice, two general approaches in hybrid wheat seeds production are being used. The first is based on the application of a chemical hybridizing agent, while the second is based on the use of cytoplasmic-genetic male sterility derived from Triticum timopheevii Zhuk. (G type cytoplasm). In this study, we present the development of R (restorer) lines for an alternative hybrid wheat system based on the cytoplasm of Aegilops crassa Boiss. (D2 type cytoplasm). Considering the cytoplasm types, it was found that different types of experimental F1 crosses required different sources of fertility restorer genes. CMS materials with T. timopheevii cytoplasm achieved the highest productivity in combination with Rf3 gene carriers. On the other hand, CMS materials with D2 cytoplasm in combination with interspecific crosses of synthetic hexaploid wheat accessions and SBEII mutants led to highly heterotic F1 hybrids. D2 cytoplasm based male sterility induction system represents a promising tool for hybrid wheat development.

Evaluating technological quality of cultivated Triticum species, interspecific, and intergeneric hybrids for wheat-based products and breeding programs

Wheat genotypes such as landraces, old cultivars, wheat species, intergeneric and interspecific wheat hybrids from the gene pools nowadays offer an alternative for new wheat products and breeding programs. The present study was carried out to evaluate the grain technological quality parameters in those kinds of wheat species and hybrids under rainfed and irrigated conditions. The results of the study showed that the neglected wheat species, Triticum petropavlovskyi having the highest sedimentation index (SI), swelling index of glutenin (SIG), macro sodium dodecyl sulfate (MSDS), and Zeleny sedimentation (ZSED) values (4.9 and 4.8; 4.7 and 4.4; 77.3 and 71.0 ml; 51.0 and 44.7 ml, respectively) in rainfed and irrigated conditions, and as well as the GlutoPeak aggregation energy (AGGEN), gluten rheological index (GRI), torque before maximum (AM) values under rainfed conditions (1589.2 cm2, 68.1 and 43.0 GPU, respectively) had remarkable high gluten strength. Among the species, Triticum ispahanicum had the highest MSDS, SI, AM, and GRI values in rainfed and irrigated conditions (48.3 and 39.3 ml; 3.0 and 2.6; 37.3 and 25.7 GPU; 56.5 and 37.7, respectively). Aegilotriticum, Triticum sphaerococcum, Triticum dicoccum had also strong gluten quality. Triticum aestivum cv. Köse 220/39 possessed better gluten quality than other old cultivars and a landrace. All those genotypes can be suggested for bread-making. On the other hand, Triticum compactum and Triticum monococcum with their weak gluten strength and soft endosperm texture could be used in soft biscuit wheat breeding programs.

Assessment of morphological and anatomical variability in Triticum species, Aegilops species, interspecific and intergeneric hybrids

Wheat species and wild relatives offer promising resources for wheat improvement and research in the current period of the genetic narrowing of modern wheat cultivars. The present study was performed to evaluate the morphological and anatomical traits of 20 diverse genotypes including Triticum and Aegilops species with intergeneric and interspecific wheat hybrids, which were compared with modern bread and durum wheat cultivars locally adapted to rainfed and irrigated conditions. The study showed that stomata density and size ranged from 55.3 to 108.6 stomata/mm2 and 401.4 to 1296 µm2, respectively, in the selected genotypes. Moving tetraploid to hexaploid genotypes, increased chromosome numbers yielded lower densities of large stomata in wheat species and hybrids. In this regard, the stomatal patterns of two hexaploid wheat hybrids and a wheat species including ‘Agrotriticum’, ‘Aegilotriticum’, and T. compactum, were of low density and large size stomata compared to T. durum cv. ‘Kunduru 1149’ with high density and small size stomata. Interestingly, the wild progenitor of the bread wheat D genome, Ae. tauschii, had a high density of the smallest stomata among the studied genotypes. The study further indicated that morphological parameters decreased under rainfed conditions compared to those under irrigated conditions, with levels varying among the genotypes. The rainfed flag leaf area and 1000-grain weight varied from 0.9 to 23.7 cm2 and from 7.3 to 61.9 g, respectively under rainfed conditions, while they ranged from 1.2 to 35.7 cm2 and 11.5 to 69.9 g under irrigated conditions. The flag leaf area had a significant and strong association with 1000-grain weight under rainfed (r2= 0.79) and irrigated (r2 = 0.77) conditions. T. turanicum and T. polonicum were characterized by the significantly highest 1000-grain weight in both rainfed and irrigated conditions. This study suggests that these wheat species with high 1000-grain weight might have promising alleles to be transferred into durum wheat to increase grain yield.

The genetic basis of cytoplasmic male sterility and fertility restoration in wheat

Hybrid wheat varieties give higher yields than conventional lines but are difficult to produce due to a lack of effective control of male fertility in breeding lines. One promising system involves the Rf1 and Rf3 genes that restore fertility of wheat plants carrying Triticum timopheevii-type cytoplasmic male sterility (T-CMS). Here, by genetic mapping and comparative sequence analyses, we identify Rf1 and Rf3 candidates that can restore normal pollen production in transgenic wheat plants carrying T-CMS. We show that Rf1 and Rf3 bind to the mitochondrial orf279 transcript and induce cleavage, preventing expression of the CMS trait. The identification of restorer genes in wheat is an important step towards the development of hybrid wheat varieties based on a CMS-Rf system. The characterisation of their mode of action brings insights into the molecular basis of CMS and fertility restoration in plants.

Additive genetic variance and covariance between relatives in synthetic wheat crosses with variable parental ploidy levels.

Cultivated bread wheat (Triticum aestivum L.) is an allohexaploid species resulting from the natural hybridization and chromosome doubling of allotetraploid durum wheat (T. turgidum) and a diploid goatgrass Aegilops tauschii Coss (Ae. tauschii). Synthetic hexaploid wheat (SHW) was developed through the interspecific hybridization of Ae. tauschii and T. turgidum, and then crossed to T. aestivum to produce synthetic hexaploid wheat derivatives (SHWDs). Owing to this founding variability, one may infer that the genetic variances of native wild populations vs improved wheat may vary due to their differential origin and evolutionary history. In this study, we partitioned the additive variance of SHW and SHWD with respect to their breed origin by fitting a hierarchical Bayesian model with heterogeneous covariance structure for breeding values to estimate variance components for each breed category, and segregation variance. Two data sets were used to test the proposed hierarchical Bayesian model, one from a multi-year multi-location field trial of SHWD and the other comprising the two species of SHW. For the SHWD, the Bayesian estimates of additive variances of grain yield from each breed category were similar for T. turgidum and Ae. tauschii, but smaller for T. aestivum. Segregation variances between Ae. tauschii—T. aestivum and T. turgidum—T. aestivum populations explained a sizable proportion of the phenotypic variance. Bayesian additive variance components and the Best Linear Unbiased Predictors (BLUPs) estimated by two well-known software programs were similar for multi-breed origin and for the sum of the breeding values by origin for both data sets. Our results support the suitability of models with heterogeneous additive genetic variances to predict breeding values in wheat crosses with variable ploidy levels.

Marker-trait association for fertility restoration using Rf8 gene in T. timopheevii based male sterile cytoplasm of wheat

Hybrid wheat research has garnered interest after a gap of few decades. Heterosis levels and effective ABR system has been continuous focus of research. Effective restoration of fertility, its genetic control however remains an unresolved issue. Among 9 reported fertility restorer genes for Triticum timopheevii cytoplasm, Rf8 has been mapped on chromosome 2DS. Two F 2 populations were used to study the efficacy and robustness of markers linked with Rf8. Data was recorded on extent of fertility restoration and three linked markers namely Xwmc503, Xwmc296 and Xwmc112 were used for this study. Among these, Xwmc503 present at 3.3 cM away from Rf8 showed significant association with fertility restoration in both the crosses. In contrast, marker Xwmc296 linked at 5.8 cM did not reveal significant association in any population. However, the third marker Xwmc112 did not get amplified in any of the populations. Xwmc503 marker can potentially be useful for selecting restorers with Rf8 gene which further could be used for transferring this very gene into potentially elite genotypes to enrich hybrid male parental pool.

The Outbreeding Enhancement and Correlation Studies in F<sub>1</sub> Hybrids of Hexaploid Wheat (<i>Triticum aestivum</i> L.) Cultivars

The current study was conducted in the experimental field of the Department of Biotechnology and Genetic Engineering, Faculty of Life Science, University of Development Alternative, Dhaka, Bangladesh during the winter season 2017-2018. The study was performed to reduce the heterotic effect and phenotypic correlation among numerous yield characters for F1 hybrids of hexaploid wheat (Triticum aestivum L.). The experimental design has consisted of six parental variants (Sonalika, Balaka, Prodip, Kanchan, Agrahani and Protiva), which were crossed and nine possible cross combinations (F1 hybrids) (Prodip × Agrahani, Balaka × Agrahani, Prodip × Protiva, Protiva × Agrahani, Agrahani × Kanchan, Kanchan × Sonalika, Protiva × Prodip, Sonalika × Agrahani, and Prodip × Kanchan) were obtained. The experimental fields were selected and arranged in a randomized complete block design with four replicates, where eight characters were studied. The mean square of the analysis of variance showed that the hybrids differed significantly (p ≤ 0.01) for all studied characters except for maturity to 75% of days and height of the plant, while the parents only had no differences in grain yield. The mean square of the parent and the F1 hybrid indicated that considerable heterosis existed in the F1 hybrids. In general, correlation coefficients indicated that the maturity to 75% of days was significant but negatively correlated with most of the yield traits, suggesting that the genotypes which became mature early may have lower yields. Plant height was also negatively correlated with grain spike−1, seed index, and harvest index. The grain yield plant−1 was significant and positively correlated with all yield traits. Correlation indicates that single or multiple production-related ingredients can be used as selection time to select plants with higher yield traits with larger grains.

ЛАБОРАТОРНАЯ ОЦЕНКА РЕГЕНЕРАНТОВ ГИБРИДНЫХ КОМБИНАЦИЙ ПШЕНИЦЫ В УСЛОВИЯХ IN VITRO И EX VITRO

Drought is the combination of climatic conditions that leads to a long-term shortage of water in the soil and air. This is one of the most common abiotic stress factors that leads to significant losses of crop yield and the emergence of a threat to food security. Researchers are actively developing ways to create drought-resistant zoned varieties of economically important agricultural crops and especially cereals as the main food resource. Such varieties should maintain a relatively high yield rate with a shortage of water in the soil and air. The aim of the work was the laboratory evaluation in vitro and ex vitro of wheat regenerants formed in the embryo culture in vitro under conditions selective for the indicator "drought resistance". Methods of embryo culture in vitro, laboratory evaluation of caryopsis viability, histological analysis, as well as statistical processing of the received results were used. Under the conditions of in vitro experiments on the selective medium simulating drought by introducing mannit at the concentration of 8% as an osmotic, regenerants of 5 hybrid wheat combinations that showed tolerance to stress were obtained. It is shown that the development of regenerants in vitro and ex vitro pass according to the same phenological phases and in the same duration as donor plants. Regenerants form caryopsises of sufficiently high quality, which is confirmed by laboratory observations of their viability and histological analysis of seedlings.

Impact of Selection on Distribution of Crop Duration Parameters in Chinese Wheat Hybrids

Impact of Selection on Distribution of Crop Duration Parameters in Chinese Wheat Hybrids

Identification of Rf9, a Gene Contributing to the Genetic Complexity of Fertility Restoration in Hybrid Wheat.

Wheat (Triticum aestivum L.) is a self-pollinating crop whose hybrids offer the potential to provide a major boost in yield. Male sterility induced by the cytoplasm of Triticum timopheevii is a powerful method for hybrid seed production. Hybrids produced by this method are often partially sterile, and full fertility restoration is crucial for wheat production using hybrid cultivars. To identify the genetic loci controlling fertility restoration in wheat, we produced two cytoplasmic male-sterile (CMS) backcross (BC1) mapping populations. The restorer lines Gerek 79 and 71R1203 were used to pollinate the male-sterile winter wheat line CMS-Sperber. Seed set and numbers of sterile spikelets per spike were evaluated in 340 and 206 individuals of the populations derived from Gerek 79 and 71R1203, respectively. Genetic maps were constructed using 930 and 994 single nucleotide polymorphism (SNP) markers, spanning 2,160 and 2,328 cM over 21 linkage groups in the two populations, respectively. Twelve quantitative trait loci (QTL) controlled fertility restoration in both BC1 populations, including a novel restorer-of-fertility (Rf) locus flanked by the SNP markers IWB72413 and IWB1550 on chromosome 6AS. The locus was mapped as a qualitative trait in the BC1 Gerek 79 population and was designated Rf9. One hundred-nineteen putative candidate genes were predicted within the QTL region on chromosome 6AS. Among them were genes encoding mitochondrial transcription termination factor and pentatricopeptide repeat-containing proteins that are known to be associated with fertility restoration. This finding is a promising step to better understand the functions of genes for improving fertility restoration in hybrid wheat.

Genome-Wide Association Mapping and Genomic Prediction of Anther Extrusion in CIMMYT Hybrid Wheat Breeding Program via Modeling Pedigree, Genomic Relationship, and Interaction With the Environment.

Anther extrusion (AE) is the most important male floral trait for hybrid wheat seed production. AE is a complex quantitative trait that is difficult to phenotype reliably in field experiments not only due to high genotype-by-environment effects but also due to the short expression window in the field condition. In this study, we conducted a genome-wide association scan (GWAS) and explored the possibility of applying genomic prediction (GP) for AE in the CIMMYT hybrid wheat breeding program. An elite set of male lines (n = 603) were phenotype for anther count (AC) and anther visual score (VS) across three field experiments in 2017–2019 and genotyped with the 20K Infinitum is elect SNP array. GWAS produced five marker trait associations with small effects. For GP, the main effects of lines (L), environment (E), genomic (G) and pedigree relationships (A), and their interaction effects with environments were used to develop seven statistical models of incremental complexity. The base model used only L and E, whereas the most complex model included L, E, G, A, and G × E and A × E. These models were evaluated in three cross-validation scenarios (CV0, CV1, and CV2). In cross-validation CV0, data from two environments were used to predict an untested environment; in random cross-validation CV1, the test set was never evaluated in any environment; and in CV2, the genotypes in the test set were evaluated in only a subset of environments. The prediction accuracies ranged from −0.03 to 0.74 for AC and −0.01 to 0.54 for VS across different models and CV schemes. For both traits, the highest prediction accuracies with low variance were observed in CV2, and inclusion of the interaction effects increased prediction accuracy for AC only. In CV0, the prediction accuracy was 0.73 and 0.45 for AC and VS, respectively, indicating the high reliability of across environment prediction. Genomic prediction appears to be a very reliable tool for AE in hybrid wheat breeding. Moreover, high prediction accuracy in CV0 demonstrates the possibility of implementing genomic selection across breeding cycles in related germplasm, aiding the rapid breeding cycle.

Application of SSR Markers for Purity Testing of Hybrid Wheat (Triticum aestivum L.)

Exploitation of the full potential of any hybrid requires the possessing of genetically high-purity seeds. In order to avoid reduction in yield caused by using low purity seeds, development of a simple, rapid, and accurate method for hybrid purity assessment is of great essence and significance. For the identification of true hybrids, SSR markers provides authentic information that will help to the further progress of any research programme. In this study, total of 40 wheat hybrids and 14 parental lines were taken for the hybrid purity analysis with 20 SSR markers. These markers were used to find out the codominant loci in the hybrid and single dominant loci in parents. Out of 20 SSR markers, only 8 markers viz., Xwmc617, Xwmc457, Xwmc48, Xgwm153, Xbarc61, Xgwm273, Xbarc268 and Xgwm274 showed the polymorphic dominant loci in the parents and co-dominant loci midway between these parents. Therefore these SSR markers were used to confirm the forty hybrids. The range of allele size produced by SSR marker on the parental lines were 120 bp to 300 bp. The highest allel size (300 bp) was produced by marker Xbarc 268 whereas, the minimum allel size (120 bp) was produced by marker Xgwm 273. All the fourty hybrids showed similar banding pattern as parental lines, this proved the purity of hybrids in all these cross combinations. The confirmation of hybrid purity indicated that a single polymorphic marker was sufficient for detection of contaminations of these hybrids from their parents.