Rice Genomics and Genetics 2024, Vol.15, No.3, 106-120 http://cropscipublisher.com/index.php/rgg 115 7.2 Abiotic stress tolerance Abiotic stresses such as drought and salinity can severely impact rice production. Developing varieties with enhanced tolerance to these stresses is essential for ensuring food security in the face of climate change. Drought stress significantly affects rice yield, and drought tolerance is a crucial trait for rice cultivation in water-scarce regions. Strategies to improve drought tolerance include multiparent-derived introgression and genomic and transcriptomic approaches. The disease-resistant introgression lines developed for ‘Krishna Hamsa’ also contain QTLs for drought tolerance. These lines not only exhibit resistance to BB and blast disease but also show improved drought tolerance. The study utilized a multi-locus introgression strategy, integrating multiple disease resistance genes and drought tolerance QTLs into ‘Krishna Hamsa’, ultimately developing 196 introgression lines with different gene/QTL combinations (Figure 4). This research demonstrates the potential for rapidly developing multi-resistant rice varieties through selective multiparent crosses combined with marker-assisted selection (Badri et al., 2022). Advances in genomics and transcriptomics have identified numerous QTLs, genes, and transcription factors involved in the drought response of rice, providing a genetic foundation for developing drought-tolerant rice varieties (Ahmad, 2022). Figure 4 Introgression scheme involving elite recurrent parent, ‘Krishna Hamsa’, and six donor parents for biotic and abiotic traits (Adopted from Badri et al., 2022) Image caption: The figure describes the process of crossing and selfing with six donor parents, each carrying genes for resistance to bacterial blight (BB), blast disease (Blast), and brown planthopper (BPH) (such as xa5, xa13, Xa21, Pi9, Pi54, Bph20, and Bph21), as well as drought tolerance QTLs (qDTY1.1, qDTY2.1, qDTY3.1, qDTY12.1). Through three rounds of selective crossing and selfing, combined with foreground selection and phenotypic evaluation, 196 introgression lines (ILs) were developed. These ILs exhibit resistance to various biotic and abiotic stresses (Adapted from Badri et al., 2022)
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