Fusarium Head Blight and Rust Diseases in Soft Red Winter Wheat in the Southeast United States: State of the Art, Challenges and Future Perspective for Breeding

Abstract

Among the biotic constraints to wheat (Triticum aestivum L.) production, fusarium head blight (FHB), caused by Fusarium graminearum, leaf rust (LR), caused by Puccinia triticina, and stripe rust (SR) caused by Puccinia striiformis are problematic fungal diseases worldwide. Each can significantly reduce grain yield while FHB causes additional food and feed safety concerns due to mycotoxin contamination of grain. Genetic resistance is the most effective and sustainable approach for managing wheat diseases. In the past 20 years, over 500 quantitative trait loci (QTLs) conferring small to moderate effects for the different FHB resistance types have been reported in wheat. Similarly, 79 Lr-genes and more than 200 QTLs and 82 Yr-genes and 140 QTLs have been reported for seedling and adult plant LR and SR resistance, respectively. Most QTLs conferring rust resistance are race-specific generally conforming to a classical gene-for-gene interaction while resistance to FHB exhibits complex polygenic inheritance with several genetic loci contributing to one resistance type. Identification and deployment of additional genes/ QTLs associated with FHB and rust resistance can expedite wheat breeding through marker-assisted and/or genomic selection to combine small-effect QTL in the gene pool. LR disease has been present in the southeast United States for decades while SR and FHB have become increasingly problematic in the past 20 years, with FHB arguably due to increased corn acreage in the region. Currently, QTLs on chromosome 1B from

Screening of Wheat Genotypes for Morphological, Physiological and Phenological Traits Under Climatic Condition

“…Our results were also in agreement of Sootaher et al [14] who worked on wheat. These results were also observed by [15], [6]. These results were also articulated by [17], [18], and suggested that the genotypes having genetic variability for different characters must be chosen for future breeding.…”

“…The global warming and climate change are changing the weather's pattern worldwide. These climatic conditions and hot weather generally affect not only the total amount of rainfall in a particular season, but also the frequency, duration, and harshness of water stress in the crops at different growth stages [6].…”

A novel adult plant leaf rust resistance gene Lr2K38 mapped on wheat chromosome 1AL

“…Yield losses of up to 40% have been reported due to LR; however, losses can vary depending upon the cultivar, LR severity, time of initial infection, rate of disease development, and disease duration (Kolmer, Jin, & Long, 2007; Zhao et al., 2008). Although several management practices, including the use of fungicides, are available and found effective to control wheat LR, the use of genetic resistance is undoubtedly the best and most preferred method to control LR disease (Ghimire et al., 2020; Kolmer, 1996). To date, 79 leaf rust resistance genes ( Lr genes) have been cataloged (Qureshi et al., 2018) and 249 QTL conferring LR resistance have been reported (Pinto da Silva et al., 2018).…”

“…Of the 79 reported Lr ‐genes, 64 are race‐specific and confer LR resistance at the seedling stage (Pinto da Silva et al., 2018). A major limitation of race‐specific resistance genes is that they are short‐lived and mutation and/or recombination in P. triticina populations can easily overcome the seedling resistance (Ghimire et al., 2020; Kolmer, 2005, 2013). For instance, two seedling Lr ‐genes, Lr10 and Lr16 , that were deployed in Canadian wheat cultivar ‘Selkirk’ were ineffective after the evolution of new virulent P. triticina races (McCallum et al., 2016).…”

Screening of Durum Wheat (Triticum turgidum L. subsp. durum (Desf.) Husn.) Italian Cultivars for Susceptibility to Fusarium Head Blight Incited by Fusarium graminearum

“…Furthermore, tests in different environmental conditions are needed to verify the susceptibility of wheat germplasm to FHB as the severity of the disease is influenced by climatic conditions and may result in a large variability of the interaction between genotype and environment [ 5 , 14 ]. Over 500 quantitative trait loci (QTLs) conferring small to moderate effects on the different FHB resistance types have been reported in wheat [ 15 , 16 ].…”