Day-neutral flowering candidate genes identified by selection mapping in an upland cotton (Gossypium hirsutum L.) RIL population

Identification of a major QTL and candidate gene for flowering time in industrial hemp via BSA-seq and fine mapping.

Findings elucidate the molecular basis of flowering time in industrial hemp and provide valuable genomic resources for breeding broadly adapted, high-yield varieties.

Mapping the genetic architecture of flowering and maturity in soybean [Glycine max (L.) Merr.] using multi-locus genome-wide association studies under Ethiopian conditions

QTL Mapping for Leaf Rust Resistance in a Wheat Recombinant Inbred Line Population of Liang66-S/Hengmai28

Leaf rust (LR), caused by Puccinia triticina, is a major constraint to global wheat production. Identifying quantitative trait loci (QTLs), conferring adult-plant resistance (APR), and developing breeder-friendly markers are essential for durable disease control. In this study, a recombinant inbred line (RIL) population derived from Liang66-S × Hengmai28 was evaluated for leaf rust severity across four environments. Maximum disease severity (MDS) showed continuous variation and moderate to high correlations among environments, indicating polygenic inheritance. Five APR QTLs were mapped on chromosomes 2BL, 3BS, 3BL, 7BL and 7DL, explaining 4.5–9.8% of the phenotypic variance (PVE) with LOD scores of 2.9–7.9. Among these, QLr.DFI-2BL, QLr.DFI-3BS, and QLr.DFI-7BL correspond to previously reported APR loci, whereas QLr.DFI-3BL and QLr.DFI-7DL represent potentially novel loci. QLr.DFI-3BL was detected across all four environments, while QLr.DFI-3BS and QLr.DFI-7BL showed the highest R2 (7.7–8.5% and 8.4–9.8%). Multiple defense-related genes within the QTL intervals for LR were identified, including the putative NBS-LRR, the putative BTB/POZ-MATH, F-box, receptor-like kinase, polyphenol oxidase, calcium-dependent protein kinase, peroxidase, and ethylene-responsive transcription factors. Based on the flanking markers, five KASP markers were developed. K-LR-3BS (for QLr.DFI-3BS) and K-LR-7BL (for QLr.DFI-7BL) successfully genotyped a natural population with 120 accessions, with call rates of 100% and 94.2%, and showed significant association with reduced leaf rust severity. However, further validation in diverse genetic backgrounds and populations is required before they can be considered for routine marker-assisted selection. These results provide two KASP markers as promising markers that require further validation in diverse backgrounds and highlight QLr.DFI-3BS and QLr.DFI-7BL as promising targets for fine mapping and eventual cloning of APR genes in wheat.

Identification of stripe rust resistance loci in Gansu wheat landraces using genome-wide association analysis

QTL detection for fruit commercial quality traits in diploid and triploid banana populations

Desert bananas (Musa spp.) are a major fruit crop worldwide for which postharvest quality traits are major determinants for consumer acceptance and adoption of new cultivars. They are thus important targeted traits in breeding yet their genetic basis remains poorly characterized. We report the first QTL mapping study of two of these quality traits, finger drop resistance and bruising susceptibility, using two biparental populations sharing the same genetic background but differing in ploidy level: a diploid Pisang Madu × Galéo population and a triploid Pisang Madu T × Galéo population. For finger drop, heritability reached 0.47 in diploids and 0.38 in triploids. Two significant QTLs, q1_FD_M7-1 and q2_FD_M11, were detected in the diploid population and together explained 28.12% of the phenotypic variance. q1_FD_M7-1 was located in a non-recombining chromosomal region associated with a reciprocal translocation in Pisang Madu. Candidate genes co-localizing with finger drop QTLs included expansins, xyloglucan endotransglucosylases, and pectin methylesterases involved in cell wall remodeling. For bruising susceptibility, heritability was higher in triploids (0.57) than in diploids (0.48). One QTL and one putative QTL detected in the triploid population together explained 28.78% of the phenotypic variance. Cross-ploidy validation showed moderate predictive ability of QTL-based models between populations, with prediction accuracies of 0.52 for finger drop and 0.42 for bruising susceptibility. These QTLs are promising targets for marker-assisted selection to accelerate the development of new desert banana cultivars which are urgently needed to diversify the current production mainly based on monoculture of Cavendish.

Identification of candidate genes associated with major QTL controlling Vertcillium wilt resistance in cotton (Gossypium hirsutum L.)