In southwestern China, a breeding strategy involving synthetic hexaploid wheat has led to the development of high-yielding wheat varieties. By pyramiding stripe rust resistance and big-spike-related QTLs/genes from synthetic hexaploid wheat into new cultivars, researchers have created wheat varieties with significantly enhanced yield potential. This strategy, known as the "large population with limited backcrossing method," has been instrumental in developing record-breaking high-yield wheat in the region (Wan et al., 2023).

 

Furthermore, the use of synthetic hexaploid wheat in Pakistan has demonstrated the potential for enhancing genetic diversity and selection signatures in modern spring wheat. A study involving 422 wheat accessions, including synthetic-derived wheats, revealed significant genetic diversity and the presence of unique genome regions associated with important agronomic traits. This research underscores the value of synthetic wheats in modern breeding programs and their role in improving wheat productivity (Ali et al., 2022).

 

These case studies illustrate the successful creation and application of synthetic wheat in various breeding programs, highlighting their potential to address future challenges in wheat production and ensure global food security.

 

3. The Genetic Foundation of Synthetic Wheat

3.1 Genetic variation in synthetic wheat lines

Synthetic wheat lines, particularly synthetic hexaploid wheats (SHWs), have been developed to reintroduce genetic diversity into modern bread wheat (Triticum aestivum L.). These synthetics are created by crossing tetraploid wheat (Triticum turgidum) with the diploid wild relative Aegilops tauschii, thereby recreating the ancestral hexaploid genome of wheat. This process has been shown to significantly enhance genetic variation, which is crucial for breeding programs aimed at improving yield, disease resistance, and stress tolerance (Ogbonnaya et al., 2013; Dunckel et al., 2017; Bhatta et al., 2019).

 

Studies have demonstrated that synthetic-derived wheat lines exhibit a broad range of genetic diversity. For instance, a study involving 422 wheat accessions, including synthetic-derived wheats, revealed high levels of genetic diversity and polymorphic information content across the A, B, and D genomes (Figure 2) (Ali et al., 2022). This diversity is not only beneficial for breeding but also for understanding the genetic architecture of important agronomic traits.

 

3.2 Genomic analyses and introgressions

Genomic analyses have been pivotal in identifying and utilizing the genetic potential of synthetic wheat lines. Techniques such as genotyping-by-sequencing (GBS) and genome-wide association studies (GWAS) have been employed to map and introgress beneficial alleles from synthetic wheats into elite cultivars. For example, a GWAS conducted on a diverse panel of hexaploid bread and synthetic wheat identified 243 significant marker-trait associations (MTAs) for various agronomic traits, including yield, disease resistance, and grain quality (Bhatta et al., 2019). These MTAs provide valuable markers for marker-assisted selection in breeding programs.

 

Introgression lines developed using synthetic octaploid wheat (Aegilops tauschii×hexaploid wheat) as donors have shown significant phenotypic variance and improved agronomic traits compared to the recurrent parent lines. This approach has led to the identification of quantitative trait loci (QTLs) for important traits such as thousand kernel weight, spike length, and plant height, further demonstrating the utility of synthetic wheats in breeding (Zhang et al., 2018).

 

3.3 Identification of unique genetic traits

The unique genetic traits introduced by synthetic wheat lines have been extensively studied and documented. These traits include enhanced yield potential, improved stress tolerance, and disease resistance. For instance, synthetic-derived lines have been shown to outperform elite parent lines in various environmental conditions, including irrigated, heat, and drought-stressed environments (Dunckel et al., 2017). This indicates that synthetic wheats contribute alleles that enhance yield and adaptability.

 

Genomic analyses have identified specific genes and genomic regions associated with these beneficial traits. For example, a study identified 89 selective sweeps in synthetic-derived wheats, with key selections co-localizing with functional genes related to earliness, grain size, drought tolerance, and vernalization (Afzal et al., 2019). These findings highlight the potential of synthetic wheats to introduce new alleles that can be harnessed for wheat improvement.

 

The use of synthetic hexaploid wheat has led to the development of high-yielding wheat varieties with enhanced disease resistance and stress tolerance. For instance, primary SHW lines have been used to develop new wheat varieties with more spikes per plant, larger grains, and higher grain yield potential (Li et al., 2014). These varieties have shown significant improvements in grain yields under both natural and artificial selection conditions.

 

Overall, the genetic foundation of synthetic wheat lies in its ability to reintroduce and harness genetic diversity from wild relatives, thereby providing a rich source of alleles for improving modern wheat cultivars. Through genomic analyses and targeted introgressions, synthetic wheats have proven to be invaluable in the quest for higher-yielding, more resilient wheat varieties.

 

4 Benefits of Synthetic Wheat in Breeding Programs

4.1 Enhanced disease and pest resistance

Synthetic hexaploid wheat (SHW) has been instrumental in introducing novel genetic diversity into modern wheat varieties, significantly enhancing their resistance to various diseases and pests. The primary SHW lines, derived from the tetraploid wheat Triticum turgidum and the wild ancestor Aegilops tauschii, have been shown to contribute elite characters such as disease resistance to new wheat varieties. These characters include resistance to rusts, septoria, barley yellow dwarf virus (BYDV), crown rot, tan spot, spot blotch, nematodes, powdery mildew, and fusarium head blight (Ogbonnaya et al., 2013; Li et al., 2014). The introgression of these resistance traits from SHW into hexaploid wheat has led to the development of wheat varieties that are more resilient to biotic stresses, thereby reducing the reliance on chemical pesticides and contributing to sustainable agricultural practices (Ogbonnaya et al., 2013; Li et al., 2014).

 

4.2 Improved abiotic stress tolerance (drought, heat, salinity)

Abiotic stress tolerance is a critical trait for wheat, especially in the context of climate change and the increasing frequency of extreme weather events. SHW has been a valuable resource for enhancing wheat's tolerance to abiotic stresses such as drought, heat, and salinity. The genetic diversity present in SHW includes alleles that confer improved tolerance to these stresses, which have been successfully introgressed into modern wheat varieties (Figure 3) (Sehgal et al., 2015; Trono and Pecchion, 2022). For instance, synthetic-derived lines have shown significant improvements in drought and heat tolerance, with novel alleles identified for these traits from landraces and SHW (Sehgal et al., 2015; Jafarzadeh et al., 2016). Additionally, SHW has been used to develop wheat varieties with enhanced tolerance to waterlogging and soil micronutrient imbalances, further broadening the environmental adaptability of wheat (Trethowan and Mujeeb-Kazi, 2016). The use of advanced breeding techniques, such as genomic selection and marker-assisted selection, has accelerated the incorporation of these beneficial traits into elite wheat cultivars, ensuring high yields under stress-prone conditions (Dunckel et al., 2017; Trono and Pecchion, 2022).

 

4.3 Yield improvement and quality traits

One of the most significant benefits of incorporating SHW into breeding programs is the potential for yield improvement and the enhancement of quality traits. SHW has been shown to contribute to higher grain yields through the introduction of favorable alleles that increase the number of spikes per plant, grains per spike, and grain size (Li et al., 2014; Jafarzadeh et al., 2016; Trethowan and Mujeeb-Kazi, 2016). For example, yield trials conducted under various environmental conditions, including irrigated, drought, and heat-stress conditions, have demonstrated that synthetic-derived lines often outperform their recurrent parents in terms of yield. The genetic diversity from SHW not only enhances yield potential but also improves other agronomic traits such as kernel weight, biomass production, and photosynthetic efficiency (Blanco et al., 2001; Merchuk-Ovnat et al., 2016).

 

Moreover, SHW has been utilized to improve grain quality traits, including protein content and gluten strength, which are essential for bread-making and other end-uses5. The introgression of novel alleles from SHW has led to the development of wheat varieties with superior quality traits, meeting the demands of both producers and consumers (Ogbonnaya et al., 2013). The combination of yield improvement and enhanced quality traits makes SHW a valuable resource for breeding programs aimed at developing high-performing wheat varieties that can thrive in diverse environments and meet the growing global demand for wheat (Ogbonnaya et al., 2013; Li et al., 2014; Trethowan and Mujeeb-Kazi, 2016).

 

In summary, the incorporation of synthetic wheat into breeding programs offers numerous benefits, including enhanced disease and pest resistance, improved abiotic stress tolerance, and significant yield and quality trait improvements. These advantages underscore the importance of leveraging genetic diversity from synthetics to ensure the continued progress and sustainability of wheat production in the face of global challenges.

 

5 Role of Synthetics in Wheat Breeding Programs

5.1 Crossbreeding techniques and strategies

The integration of synthetic hexaploid wheat (SHW) into wheat breeding programs has been a pivotal strategy to enhance genetic diversity and improve yield potential. One effective crossbreeding technique involves the use of double top-cross (DTC) strategies. In this method, one parent is a synthetic hexaploid wheat, and the other is an elite wheat cultivar. This approach has been shown to successfully introgress one-eighth of the synthetic hexaploid wheat genome into the progeny, resulting in high-yielding wheat varieties (Hao et al., 2019). The DTC strategy, followed by a two-phase selection process, has led to the development of varieties such as Shumai 580, Shumai 969, and Shumai 830, which exhibit enhanced yield potential compared to those developed through conventional breeding methods (Hao et al., 2019).

 

Another crossbreeding strategy involves the use of synthetic backcross-derived lines (SBLs). These lines are created by backcrossing SHWs with elite bread wheat varieties. This method has been effective in introducing novel alleles from SHWs into the breeding germplasm, thereby broadening the genetic base of elite wheat varieties (Zhang et al., 2004). The use of SBLs has shown significant yield increases and improved performance across diverse environments, particularly in moisture-limited conditions (Ogbonnaya et al., 2013).

 

5.2 Genomic selection approaches

Genomic selection (GS) has emerged as a powerful tool to accelerate the introgression of exotic germplasm into elite wheat varieties. By using whole-genome profiles generated through genotyping-by-sequencing, researchers can apply various prediction models to select desirable traits more efficiently. For instance, in a study involving double haploid and recombinant inbred line populations derived from primary synthetics and the elite cultivar 'Opata M85', several synthetic-derived lines outperformed the elite parent in various environments, indicating the potential of primary synthetics to contribute alleles that increase yield (Dunckel et al., 2017). Although the prediction models had moderate predictive ability, they demonstrated the feasibility of using GS to enhance the speed of introgression of exotic alleles (Dunckel et al., 2017).

 

The BREEDWHEAT project has also contributed significantly to the development of genomic tools and methodologies for implementing GS. This project has provided high-throughput genomic tools, including SNP arrays and high-density molecular marker maps, which are essential for genome-wide association studies (GWAS) and phenomic selection (Paux et al., 2022). These tools facilitate the detection of genomic regions involved in agronomical traits, thereby aiding breeders in the development of new, high-yielding wheat varieties that are more resilient to biotic and abiotic stresses (Paux et al., 2022).

 

5.3 Integration into elite wheat germplasm

The integration of synthetic wheats into elite wheat germplasm has been a critical step in enhancing the genetic diversity and adaptive evolution of modern wheat varieties. Synthetic hexaploid wheats, recreated from the tetraploid wheat Triticum turgidum and the diploid wild relative Aegilops tauschii, have been used to introduce new genes for various productivity traits, including resistance to abiotic and biotic stresses (Ogbonnaya et al., 2013). The use of SHWs has led to the development of high-yielding wheat varieties with improved disease resistance, more spikes per plant, larger grains, and higher grain-yield potential (Li et al., 2014).

 

The mobilization of genetic variation from germplasm banks to breeding programs has also been an important strategy for sustaining crop genetic improvement. For example, the molecular diversity of 1 423 spring bread wheat accessions was investigated using high-quality genotyping-by-sequencing loci and gene-based markers for various adaptive and quality traits. This study revealed that synthetic hexaploids are genetically more diverse than elite and landrace varieties, opening new avenues for pre-breeding by enriching elite germplasm with novel alleles for drought and heat tolerance (Sehgal et al., 2015).

 

Furthermore, the rapid introgression platform established for transferring the genetic variations of Aegilops tauschii to elite wheats has enriched the wheat germplasm pool. This platform has generated synthetic octoploid wheat pools, which have shown great potential for wheat breeding, as confirmed by laboratory and field analyses. The integration of these diverse genetic resources into elite wheat germplasm has significantly contributed to the development of high-yielding, stress-resistant wheat varieties, thereby enhancing global wheat productivity and food security (Mujeeb-Kazi et al., 2013).

 

6 Methodologies for Characterizing and Utilizing Synthetic Wheat

6.1 Marker-assisted selection (MAS) and genomic selection

Marker-assisted selection (MAS) and genomic selection (GS) are pivotal methodologies in modern wheat breeding, particularly for leveraging genetic diversity from synthetic wheat. MAS involves the use of molecular markers to assist in the selection of desirable traits, which can significantly enhance the efficiency and precision of breeding programs. Various types of molecular markers, such as single nucleotide polymorphisms (SNPs), have been effectively utilized in plant breeding (He et al., 2014). The advent of next-generation sequencing (NGS) technologies has further revolutionized MAS by enabling high-throughput genotyping and the discovery of new markers through techniques like genotyping-by-sequencing (GBS) (He et al., 2014).

 

MAS has been successfully applied to improve disease resistance in wheat, with notable examples including the transfer of resistance genes such as Lr34 and Yr36 for rust resistance, and Fhb1 for Fusarium head blight resistance (Miedaner and Korzun, 2012). However, MAS is often limited by the small effects of individual quantitative trait loci (QTL) and the complexity of polygenic traits (Gupta et al., 2010; Miedaner and Korzun, 2012). To address these limitations, genomic selection (GS) has emerged as a more comprehensive approach. GS uses genome-wide marker data to predict the genetic value of selection candidates, capturing both small and large effect QTLs (Heffner et al., 2011). Studies have shown that GS can achieve higher prediction accuracies than conventional MAS, making it a promising tool for improving complex traits in wheat (Heffner et al., 2011; Arruda et al., 2016).

 

6.2 Advanced backcross QTL analysis

Advanced backcross QTL (AB-QTL) analysis is a powerful method for identifying and utilizing beneficial alleles from wild relatives of wheat. This approach involves backcrossing a wild relative with an elite cultivar and then using molecular markers to identify QTLs associated with desirable traits. For instance, a study involving a cross between the German winter wheat variety 'Prinz' and the synthetic wheat line W-7984 identified 40 putative QTLs for yield and yield components (Huang et al., 2003). Despite the overall inferior agronomic performance of the synthetic wheat, 60% of the identified QTLs from W-7984 had positive effects on agronomic traits, demonstrating the potential of AB-QTL analysis to transfer favorable alleles from wild relatives into elite wheat varieties (Huang et al., 2003).

 

The AB-QTL strategy has been particularly effective in improving complex traits such as yield, where multiple QTLs contribute to the overall performance. By integrating molecular breeding techniques with traditional backcrossing, breeders can more efficiently incorporate beneficial alleles from synthetic wheat into commercial cultivars, thereby enhancing genetic diversity and improving crop performance (Huang et al., 2003).

 

6.3 Use of high-throughput phenotyping

High-throughput phenotyping (HTP) is an essential tool for characterizing and utilizing synthetic wheat in breeding programs. HTP involves the use of advanced imaging and sensor technologies to rapidly and accurately measure a wide range of phenotypic traits in large populations. This approach allows for the collection of extensive phenotypic data, which can be integrated with genotypic information to identify and select superior genotypes (Gupta et al., 2010; He et al., 2014).

 

The integration of HTP with MAS and GS can significantly enhance the efficiency of breeding programs. For example, HTP can be used to measure traits such as plant height, biomass, and disease resistance, which are then correlated with molecular marker data to identify QTLs and predict genetic values (Gupta et al., 2010; He et al., 2014). This combined approach enables breeders to make more informed selection decisions, accelerating the development of improved wheat varieties.

 

The methodologies of MAS, GS, AB-QTL analysis, and HTP are critical for leveraging the genetic diversity of synthetic wheat. These advanced techniques enable the precise identification and utilization of beneficial alleles, ultimately leading to the development of superior wheat cultivars with enhanced performance and resilience. By integrating these methodologies, breeders can more effectively harness the potential of synthetic wheat to address the challenges of modern agriculture.

 

7 Case Studies of Synthetic Wheat in Breeding Programs

7.1 CIMMYT mexico

The International Maize and Wheat Improvement Center (CIMMYT) has been at the forefront of utilizing synthetic hexaploid wheat (SHW) to enhance the genetic diversity and performance of bread wheat. CIMMYT has produced over 1 000 SHWs by crossing diverse accessions of the D genome donor species, Aegilops tauschii, with tetraploid wheat, Triticum turgidum. These SHWs have shown significant resistance or tolerance to various biotic and abiotic stresses, making them valuable for breeding programs aimed at improving yield and stress tolerance (Dreisigacker et al., 2008).

 

The SHWs were backcrossed with CIMMYT's improved germplasm to produce synthetic backcross-derived lines (SBLs). These SBLs retain the beneficial traits of SHWs while being agronomically similar to the improved parents. Molecular studies have shown that SHWs and SBLs are genetically diverse compared to traditional bread wheat cultivars, with preferential transmission of some alleles from the SHW parent, indicating positive selection. This genetic diversity has been instrumental in increasing yield and enhancing disease resistance in wheat cultivars developed by CIMMYT (Ogbonnaya et al., 2013).

 

CIMMYT's breeding strategy has also focused on targeting the A and B genomes of hexaploid wheat to improve specific traits. For instance, screening the germplasm collection of T. turgidum subsp. dicoccum for resistance to Russian wheat aphid and drought tolerance has led to the identification of promising accessions for future SHW production and introgression into elite bread wheat backgrounds (Dreisigacker et al., 2008). This approach has resulted in significant genetic gains for grain yield in semi-arid environments, demonstrating the potential of SHWs to improve wheat productivity under suboptimal conditions (Crespo-Herrera et al., 2018).

 

7.2 Southwest China

In Southwest China, synthetic hexaploid wheat has been extensively utilized to combat rust resistance and improve yield. The primary SHW lines have been used to develop high-yielding wheat varieties with enhanced disease resistance and yield potential. For example, four high-yielding wheat varieties have been developed using primary SHW lines, and 12 new wheat varieties have been created using SHW-derived varieties as breeding parents (Li et al., 2014).

 

The breeding strategy in Southwest China involves pyramiding quantitative trait loci (QTLs) from SHW into new high-yield cultivars. This approach has led to the development of big-spike wheat varieties with improved yield and resistance to stripe rust. The "large population with limited backcrossing method" and the "recombinant inbred line-based breeding method" have been employed to combine phenotypic and genotypic evaluations, resulting in record-breaking high-yield wheat varieties (Wan et al., 2023).

 

The introgressed alleles from SHW lines have contributed significantly to the new wheat varieties, enhancing traits such as disease resistance, more spikes per plant, more grains per spike, larger grains, and higher grain yield potential. These findings highlight the importance of SHW as a genetic resource for breeding high-yielding wheat varieties resistant to biotic and abiotic stresses (Li et al., 2014).

 

7.3 India

In India, the adoption of synthetic hexaploid wheat has been pivotal in improving resistance to pests and pathogens and enhancing yield potential. The genetic diversity introduced by SHWs has been harnessed to develop wheat varieties with improved resistance to various biotic stresses, including rusts, septoria, and fusarium head blight (Ogbonnaya et al., 2013).

 

The breeding programs in India have focused on utilizing SHWs to pyramid QTLs for resistance to multiple pests and pathogens. This approach has led to the development of wheat varieties with enhanced resistance to biotic stresses and improved yield potential. The success of these breeding efforts underscores the value of SHWs in addressing the challenges posed by pests and pathogens in wheat cultivation (Ogbonnaya et al., 2013).

 

Moreover, the integration of SHWs into Indian breeding programs has resulted in the development of high-yielding wheat varieties that are well-adapted to local environmental conditions. The genetic diversity and novel alleles introduced by SHWs have played a crucial role in enhancing the yield potential and stress tolerance of these wheat varieties, contributing to the overall improvement of wheat productivity in India (Ogbonnaya et al., 2013).

 

In conclusion, the case studies from CIMMYT Mexico, Southwest China, and India demonstrate the significant impact of synthetic hexaploid wheat in breeding programs. The genetic diversity and novel traits introduced by SHWs have led to the development of high-yielding, disease-resistant wheat varieties, highlighting the potential of SHWs to improve wheat productivity and resilience to biotic and abiotic stresses globally.

 

8 Challenges and Limitations

8.1 Technical and logistical challenges

Leveraging genetic diversity from synthetics for wheat improvement presents several technical and logistical challenges. One of the primary technical hurdles is the complexity of chromosome engineering, which involves the incorporation of targeted chromosomal segments from wild relatives into wheat chromosomes. This process, although promising, requires advanced cytogenetic methodologies and precise manipulation of genomes, which can be technically demanding and resource-intensive. Additionally, the introgression of exotic germplasm often brings along undesirable traits, making direct use in breeding programs difficult. This necessitates the development of sophisticated genomic selection approaches to enable rapid cycles of selection, which can be restricted by complex physiological effects (Dunckel et al., 2017).

 

Logistically, the process of identifying and mobilizing useful genetic variation from germplasm banks to breeding programs is a significant challenge. The vast diversity within gene banks requires extensive screening and evaluation to identify beneficial traits, which is both time-consuming and labor-intensive (Sehgal et al., 2015). Furthermore, the production and maintenance of synthetic hexaploid wheats (SHWs) involve intricate breeding strategies and large-scale field trials to assess their performance under various environmental conditions, adding to the logistical burden (Ogbonnaya et al., 2013).

 

8.2 Genetic stability and performance issues

The genetic stability and performance of synthetic-derived wheat lines are critical concerns. While SHWs are valuable for introducing new genes for stress resistance and yield improvement, they often exhibit genetic instability due to the complex interactions between the introduced and native genomes. This instability can lead to unpredictable performance in different environments, posing a challenge for breeders (Mujeeb-Kazi et al., 2015). Moreover, the recombination and reassortment within the synthetic genomes can generate novel gene combinations, but these may not always result in desirable agronomic traits, necessitating further selection and breeding efforts (Wan et al., 2023).

 

Another issue is the potential for linkage drag, where undesirable traits are co-inherited with beneficial ones, complicating the breeding process. This is particularly problematic when dealing with genes from the tertiary gene pool, which often involve intergeneric crosses and can result in significant genetic incompatibilities (Mujeeb-Kazi et al., 2015). Additionally, the introgression of exotic alleles can sometimes lead to reduced fitness or adaptability in the target environment, requiring careful management and selection to ensure stable performance (Hao et al., 2019).

 

8.3 Economic and regulatory considerations

Economic and regulatory considerations also play a crucial role in the adoption and implementation of synthetic-derived wheat improvement strategies. The development and deployment of SHWs and other genetically diverse lines require substantial financial investment in research, breeding, and field trials. This can be a significant barrier, especially for resource-limited breeding programs and institutions (Ogbonnaya et al., 2013). Furthermore, the commercialization of new wheat varieties derived from synthetic sources may face regulatory hurdles, particularly concerning biosafety and environmental impact assessments (Li et al., 2021).

 

Regulatory frameworks governing the use of genetically modified organisms (GMOs) and advanced breeding techniques vary widely across different regions, potentially limiting the global adoption of these technologies. For instance, genome editing and other molecular breeding strategies, while promising, are subject to stringent regulatory scrutiny, which can delay the release of new varieties and increase the cost of compliance (Li et al., 2021). Additionally, public perception and acceptance of genetically modified crops can influence market dynamics and the economic viability of synthetic-derived wheat varieties.

 

In conclusion, while leveraging genetic diversity from synthetics offers significant potential for wheat improvement, it is accompanied by a range of challenges and limitations. Addressing these issues requires a concerted effort involving advanced technical methodologies, robust breeding strategies, and supportive economic and regulatory frameworks to ensure the successful integration of synthetic-derived genetic diversity into wheat breeding programs.

 

9 Future Directions and Opportunities

9.1 Potential for new synthetic wheat lines

The development of new synthetic wheat lines holds significant promise for the future of wheat improvement. Synthetic wheat lines, created by crossing durum wheat with various Aegilops species, have already demonstrated their potential to introduce valuable genetic diversity into bread wheat. For instance, synthetic hexaploid wheats (SHWs) derived from crosses between durum wheat and Aegilops tauschii have been shown to enhance traits such as disease resistance, yield stability, and industrial quality (Zaïma et al, 2017; Mirzaghaderi et al., 2020; Aberkane et al., 2020). The production of synthetic wheat lines has also been successful in generating stable amphiploids with diverse genetic backgrounds, which are valuable resources for breeding programs (Mirzaghaderi et al., 2020). Furthermore, synthetic wheat lines have been utilized to transfer desirable traits from wild relatives to modern wheat varieties, resulting in improved resistance to pests and pathogens, high yield potential, and good quality attributes (Aberkane et al., 2020). The continued exploration and development of new synthetic wheat lines, including those involving less-investigated species like Aegilops umbellulata, will be crucial for broadening the genetic base of wheat and addressing future challenges in wheat production (Okada et al., 2020).

 

9.2 Innovations in breeding technologies

The advent of advanced breeding technologies, such as CRISPR and other gene-editing tools, presents exciting opportunities for accelerating wheat improvement. CRISPR technology allows for precise and targeted modifications of the wheat genome, enabling the introduction of beneficial traits with greater efficiency and accuracy compared to traditional breeding methods. For example, CRISPR has been used to enhance disease resistance, improve grain quality, and increase yield potential in wheat (Ginkel et al., 2007). Additionally, the use of molecular markers, such as SSR markers, has facilitated the identification and selection of desirable alleles in synthetic wheat lines and their backcross-derived lines, further enhancing the efficiency of breeding programs (Zhang et al., 2004). The integration of these innovative technologies with traditional breeding approaches will enable the development of wheat varieties that are better adapted to changing environmental conditions and capable of meeting the growing global demand for food.

 

9.3 Strategic recommendations for future research and breeding programs

To fully leverage the potential of synthetic wheat lines and advanced breeding technologies, several strategic recommendations can be made for future research and breeding programs. It is essential to continue the exploration and utilization of genetic diversity from wild relatives of wheat. This includes not only the well-studied Aegilops tauschii but also other species such as Aegilops umbellulata and Triticum dicoccoides, which have been shown to contribute valuable traits to synthetic wheat lines (Mirzaghaderi et al., 2020; Okada et al., 2020). Collaborative efforts between international research institutions and genebanks will be crucial for accessing and conserving these genetic resources.

 

The integration of advanced breeding technologies, such as CRISPR and molecular markers, into breeding programs should be prioritized. These technologies can significantly enhance the efficiency and precision of breeding efforts, allowing for the rapid development of wheat varieties with improved traits. Training and capacity-building initiatives for researchers and breeders in the use of these technologies will be essential for their successful implementation.

 

Breeding programs should focus on developing wheat varieties that are resilient to biotic and abiotic stresses, such as diseases, pests, drought, and heat. The use of synthetic wheat lines, which have demonstrated resistance to major wheat diseases and tolerance to abiotic stresses, will be instrumental in achieving this goal (Ginkel et al., 2007). Additionally, breeding efforts should aim to improve the nutritional quality of wheat, including the development of biofortified varieties that can address micronutrient deficiencies in human populations (Aberkane et al., 2020).

 

It is important to establish robust evaluation and testing protocols for new wheat varieties. This includes multi-environment trials to assess the performance and stability of synthetic wheat lines and their derivatives under diverse growing conditions (Zaïma et al, 2017). The involvement of farmers and end-users in the evaluation process will ensure that the developed varieties meet the needs and preferences of the target communities.

 

The future of wheat improvement lies in the strategic integration of genetic diversity from synthetic wheat lines and the application of advanced breeding technologies. By following these recommendations, researchers and breeders can develop wheat varieties that are resilient, high-yielding, and nutritionally superior, thereby contributing to global food security and sustainable agriculture.

 

10 Concluding Remarks

The study on leveraging genetic diversity from synthetic wheat has yielded several significant findings. Synthetic hexaploid wheat (SHW) has been identified as a rich source of genetic diversity, surpassing that of elite and landrace varieties This diversity has been effectively utilized to enhance various agronomic traits, including disease resistance, yield potential, and adaptability to abiotic stresses such as drought and heat. The introduction of novel alleles from SHW has led to the development of high-yielding wheat varieties with improved performance under diverse environmental conditions. Additionally, genomic selection and genome-wide association studies (GWAS) have been instrumental in identifying key genetic regions and markers associated with desirable traits, facilitating the rapid introgression of beneficial alleles into breeding programs.

 

Synthetic wheat plays a crucial role in the future of wheat improvement by serving as a reservoir of genetic diversity that can be tapped to address the challenges posed by climate change and the growing global demand for food. The ability of SHW to introduce novel genetic variations into the wheat gene pool makes it an invaluable resource for breeding programs aimed at developing resilient and high-yielding wheat varieties. The use of SHW-derived lines has already demonstrated significant improvements in yield, disease resistance, and stress tolerance, highlighting their potential to enhance wheat productivity and sustainability. As breeding techniques continue to evolve, the integration of SHW into modern breeding strategies will be essential for achieving long-term food security and agricultural sustainability.

 

Leveraging genetic diversity from synthetic wheat is a promising strategy for sustainable agriculture. The incorporation of diverse genetic material from SHW into elite wheat cultivars not only enhances their agronomic performance but also contributes to the stability and resilience of wheat production systems. By harnessing the genetic potential of SHW, breeders can develop wheat varieties that are better equipped to withstand biotic and abiotic stresses, thereby ensuring consistent yields in the face of environmental uncertainties. Moving forward, it is imperative to continue exploring and utilizing the genetic diversity present in SHW and other wild relatives to create a more robust and sustainable agricultural landscape. The ongoing efforts to map and understand the genetic basis of key traits in SHW will further enable the targeted breeding of wheat varieties that meet the demands of a changing world.

 

Acknowledgments

The author extends sincere thanks to two anonymous peer reviewers for their feedback on the manuscript.

 

Conflict of Interest Disclosure

The author affirms that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

 

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