Triticeae Genomics and Genetics, 2025, Vol.16, No.4, 184-194 http://cropscipublisher.com/index.php/tgg 189 5.2 Deployment of Fhb1 andFhb2 for Fusarium resistance Fhb1 and Fhb2 are two important QTLs that can improve wheat resistance to Fusarium head blight. When the researchers put these two genes together, they found that wheat was more resistant to the disease. Marker-assisted selection technology makes this gene combination possible. Experimental results show that wheat materials with both Fhb1 and Fhb2 have less severe diseases and better grain quality than those with only one gene. This shows that combining multiple disease resistance genes to deal with complex diseases such as Fusarium head blight is more effective (Laroche et al., 2019; Fedak et al., 2021). 5.3 Multi-locus stacking of genes using marker-assisted backcrossing Marker-assisted backcrossing (MABC) is a very useful tool that can combine multiple disease resistance genes into a good variety. Now many studies have successfully achieved the aggregation of disease resistance genes using it. For example, some breeding efforts have integrated rust resistance genes such as Yr36, Yr15, Lr24, and Sr24 into new varieties along with genes that improve grain quality. As a result, these new varieties not only have high yields and good protein content, but are also resistant to multiple rust diseases (Gautam et al., 2020; Gupta et al., 2021). Another example is the aggregation of powdery mildew resistance genes Pm2, Pm4a, and Pm21. Using molecular markers, researchers screened for double homozygotes carrying these genes. The resulting wheat varieties are both disease-resistant and maintain good agronomic traits (Liu et al., 2000). These examples show that with the help of molecular tools, gene aggregation has become faster and more accurate. This method can breed new wheat varieties that are resistant to multiple diseases and maintain good quality, and has a promising future. 6 Assessment of Resistance Effectiveness and Agronomic Traits 6.1 Evaluation of resistance spectrum under field conditions Field trials are particularly important for judging the disease resistance of wheat varieties. Diseases such as rust and fusarium need to be tested under natural infection so that the results are more realistic. Studies have found that different wheat varieties (including local varieties and improved varieties) have very different disease resistance performance in the field, ranging from high resistance to susceptibility (Zhang et al., 2022; Maulenbay et al., 2023). For example, a study used field scoring to evaluate wheat resistance to stripe rust, found some strong genotypes (scored 0-TR), and identified some key disease resistance genes, such as Yr-05, Yr-10 and Yr-15 (Khan et al., 2025). In addition, multi-year trials in multiple locations can further confirm which varieties still maintain stable resistance in different locations and seasons (Megahed et al., 2022; Mulugeta et al., 2024). 6.2 Impact on yield, plant architecture, and grain quality Combining multiple disease resistance genes not only enhances resistance, but may also affect yield and other agronomic traits. Some studies have found that certain disease resistance QTLs are linked to genes that control plant height, heading date, ear shape, and grain quality, so that disease resistance can be improved while yield and quality can be improved (Berraies et al., 2023; Xu et al., 2023). For example, the wheat variety Guinong No. 29 is a typical example. It has both disease resistance genes and excellent agronomic traits, is short, has good yield, and is suitable for baking. It can also resist a variety of diseases (Xiao et al., 2024). Now, through molecular marker-assisted selection, breeders have successfully bred a batch of new materials that are both disease-resistant and do not affect yield and quality (Bhatta et al., 2019; Zhang et al., 2022). 6.3 Stability of resistance under variable environments A good disease-resistant wheat variety is not only disease-resistant in one environment, but also stable in various environments. Current studies have shown that some varieties perform well in different locations and years, and can maintain disease resistance and yield even under adverse conditions such as high temperature or drought (Li et al., 2019; Mulugeta et al., 2024). For example, some genotypes can stably resist stripe rust at different sowing times and in different fields, while maintaining high yields, which shows that they have strong adaptability. Materials like this are particularly suitable for breeding needs in the context of climate change (Megahed et al., 2022; Ogutu et al., 2024).
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