Triticeae Genomics and Genetics, 2024, Vol.15, No.4, 185-195 http://cropscipublisher.com/index.php/tgg 188 Figure 2 Distribution of projected quantitative trait loci (QTLs) across the wheat (Triticum aestivumL.) chromosomes (Adopted from Shariatipour et al., 2021) Image caption: The numbers inside each parenthesis represent the number of QTLs (Adopted from Shariatipour et al., 2021) In the spring wheat cross 'Louise'×'Penawawa', QTLs associated with seedling growth habit, leaf color, plant height, flowering date, maturity date, grain volume weight, grain protein content, and grain yield were mapped. Notably, QTLs for flowering date and maturity date were linked to the PpdD1 gene for photoperiod insensitivity, while QTLs for plant height were localized to chromosomes 2D and 3B, demonstrating the pleiotropic effects of the PpdD1 gene (Guan et al., 2018). 3.2 QTL analysis in barley (Hordeum vulgare) Barley, another important member of the Triticeae tribe, has also been the focus of extensive QTL mapping studies. These studies have aimed to improve traits such as yield, disease resistance, and stress tolerance. For example, a high-density genetic map of barley was used to identify QTLs for yield and yield components under various environmental conditions. This map revealed clusters of QTLs on chromosomes 1H, 2H, and 3H, which were associated with traits like grain number per spike and thousand grain weight (Backes et al., 1995). In another study, QTLs for agronomic traits such as plant height, flowering time, and grain yield were mapped in a barley population derived from a cross between two elite cultivars. The study identified several QTLs with significant effects on these traits, providing valuable markers for marker-assisted selection (MAS) in barley breeding programs (Tshikunde et al., 2019). 3.3 QTL studies in other Triticeae species Beyond wheat and barley, QTL mapping has been applied to other Triticeae species to enhance our understanding of their genetic architecture and improve their agronomic performance. For instance, in intermediate wheatgrass (Thinopyrum intermedium), a perennial grass related to wheat, QTL mapping identified 111 QTLs associated with traits such as seed size, shattering, threshing, and fertility. This study highlighted the potential of using QTLs to accelerate the domestication of intermediate wheatgrass for dual-purpose forage and grain production (Ilyas et al., 2019). In hexaploid wheat, a study involving a population of 96 doubled haploid lines from the cross Chinese Spring × SQ1 identified QTLs for yield and yield components across various stress conditions. The study found that yield QTLs were widely distributed around the genome, with significant clusters on chromosomes 1D, 4B, and 7A.
RkJQdWJsaXNoZXIy MjQ4ODYzNQ==