Saline-alkali soils are quietly swallowing the world’s farmland, and a team of plant geneticists in China has unveiled a new arsenal to fight back. Researchers led by Xianfei Hou, Yuanguo Gu, and Jinxiong Shen, working at Huazhong Agricultural University and the Xinjiang Academy of Agricultural Sciences, have developed a comprehensive set of molecular markers and a genotyping chip designed to accelerate the breeding of rapeseed varieties that can thrive on salt-damaged land. The study, published in Theoretical and Applied Genetics, reports the creation of 947 molecular markers tied to saline-alkali tolerance, together with a 5,000-marker liquid-phase genotyping chip, giving breeders practical tools to select tolerant plants at the seedling stage rather than waiting an entire growing season to see which crosses survive in the field.
The scale of the underlying problem is difficult to overstate. According to recent global assessments, including the Food and Agriculture Organization’s 2024 report on salt-affected soils and a 2021 modeling study in Nature Communications predicting widespread primary soil salinization under climate change, hundreds of millions of hectares of arable land are degraded by excess salts and alkaline salts. Unlike pure salinity stress, saline-alkali stress combines osmotic pressure, sodium toxicity, and high soil pH, which disrupts nutrient uptake and root development in tandem. Rapeseed (Brassica napus L.), one of the world’s most important oilseed crops and a major source of vegetable oil, is known to tolerate these conditions better than many staple crops, making it a prime candidate for the sustainable utilization and rehabilitation of saline-alkaline soils. Yet breeding improved cultivars has remained slow, relying overwhelmingly on conventional hybridization combined with phenotype-based selection, a process that can take many years to achieve meaningful gains.
To overcome this bottleneck, the research team assembled a catalog of previously reported saline-alkali tolerance genes not only from rapeseed itself but from rice, maize, wheat, sorghum, and the model plant Arabidopsis. This cross-species strategy reflects a growing recognition that the molecular machinery of salt tolerance, including sodium transporters, ion homeostasis regulators, and osmotic adjustment pathways, is broadly conserved across plants. Classic examples include the rice quantitative trait locus encoding a sodium transporter identified in Nature Genetics in 2005, and decades of physiological work by researchers such as Munns and Tester, who dissected the mechanisms by which plants exclude sodium, compartmentalize ions in vacuoles, and maintain potassium nutrition under salt stress. By gathering homologous candidate genes from across these species, the team built a target list that could be mined for natural variation within the rapeseed genome.
The core of the study was a candidate gene-based association analysis. Using resequencing data aligned to the rapeseed reference genome, the researchers identified genetic variants, including single nucleotide polymorphisms and insertion-deletion (InDel) polymorphisms, within and around the candidate genes, then tested whether specific variants were statistically associated with saline-alkali tolerance traits in a diverse rapeseed population. Association analyses of this kind rely on mixed-model statistical frameworks, such as those implemented in widely used tools like GEMMA and PLINK, to correct for population structure and relatedness that would otherwise produce spurious correlations. The team’s rigorous approach, incorporating false discovery rate control using methods descended from the Benjamini-Hochberg procedure, paid off: 483 genes were found to be significantly associated with tolerance, and among these, 355 genes contained favorable haplotypes, meaning particular combinations of alleles linked to better performance under saline-alkali conditions.
From these significantly associated genes, the researchers successfully developed molecular markers for 275 genes. The marker set comprises 746 KASP marker pairs and 201 InDel marker pairs. KASP, or Kompetitive Allele-Specific PCR, is a fluorescence-based genotyping chemistry that distinguishes allele variants using allele-specific primers carrying distinct fluorophore tags, allowing a simple end-point readout of an individual plant’s genotype at each locus. It has become a workhorse of modern crop breeding because it is relatively inexpensive, highly accurate, and amenable to high-throughput automation, particularly when coupled to scoring systems that separate samples into clean genotype clusters. InDel markers, by contrast, exploit small insertions and deletions in the genome and provide a complementary, often co-dominant means of tracking chromosome segments during crossing. Four marker pairs were randomly selected from the newly developed set and experimentally validated, confirming that the markers faithfully distinguish the intended alleles.
In parallel with the marker development, the team constructed a 5K cGPS liquid-phase genotyping chip, designated HZSW-cGPS-BRNAP-04. Unlike traditional silicon-based solid chips, liquid-phase chips rely on targeted sequencing of a predefined panel of loci, in this case roughly 5,000 informative sites distributed across the rapeseed genome and concentrated in regions relevant to saline-alkali tolerance. The performance testing showed a high call rate, meaning the proportion of loci successfully genotyped in each sample, and excellent reproducibility, indicating that repeated genotyping of the same material yields consistent results. These quality metrics are essential for a breeding tool: a chip that fails to call genotypes reliably at low cost cannot support the routine screening of thousands of seedlings. Liquid-phase designs also offer flexibility, since marker panels can be updated as new tolerance loci are discovered, and they sidestep some of the manufacturing rigidity and cost constraints of fixed microarray platforms.
The practical payoff lies in marker-assisted selection, or MAS. In a conventional rapeseed breeding program, a breeder crosses a tolerant parent with a high-yielding elite cultivar, then spends generations measuring performance in saline field nurseries, an expensive and weather-dependent process complicated by the fact that tolerance is a quantitative trait influenced by many genes and strongly affected by the environment. With the new marker set, breeders can instead screen seedlings in trays with a few drops of DNA extract, identifying which individuals carry the favorable alleles at 275 tolerance-associated genes within days of germination. This early-generation evaluation allows breeders to discard susceptible material before it ever reaches the field, stack multiple favorable haplotypes in a single line through repeated crossing, and dramatically compress the timeline for delivering tolerant cultivars to farmers. The approach also lays the groundwork for molecular design breeding, in which crosses are planned computationally by combining known favorable alleles across the genome, and the study’s data on haplotypes and associated genes provide a functional framework for such designs.
The choice of rapeseed is itself a strategic one. The crop has emerged as a leading candidate for “green rehabilitation” of degraded land, because a crop that tolerates saline-alkali conditions both produces oil on otherwise unproductive soil and can contribute to improving soil properties through cultivation. Prior work by some of the same groups, including genome-wide association studies of salt tolerance traits in rapeseed and transcriptomic and metabolomic dissection of the elite salt-tolerant cultivar Huayouza 62, had accumulated the genetic and mechanistic knowledge that made marker development feasible. The new study consolidates that dispersed knowledge, much of it scattered across candidate gene reports from six species, into a single, validated, breeding-ready toolkit. The pan-genome resources now available for B. napus, built from multiple high-quality assemblies, further ensured that the markers capture the allelic diversity present in the species rather than the variants of a single reference line.
Funding for the work came from China’s agricultural science and technology renovation programs, the STI 2030 major project, and the Natural Science Foundation of China, reflecting the national priority placed on reclaiming saline-alkaline land, a matter of acute significance given that China alone holds tens of millions of hectares of salt-affected soils, with substantial acreage in the Xinjiang region where co-authors from the Xinjiang Academy of Agricultural Sciences are based. The authors note that the markers and the HZSW-cGPS-BRNAP-04 chip are expected to improve the breeding efficiency of saline-alkaline-tolerant rapeseed cultivars, and the supplementary data accompanying the paper, released as a downloadable file, should allow breeding programs in other countries to adopt the tools directly.
More broadly, the study illustrates how the pieces of modern plant genetics can be assembled into a working pipeline: conserved candidate genes from comparative genomics, dense sequence variation from resequencing, statistical association mapping, and high-throughput genotyping chemistry, all converging on a single agronomic goal. As climate change accelerates soil salinization and pressure mounts to feed a growing population without expanding cropland, tools that let breeders select for resilience in a petri dish rather than a salt field may prove among the most consequential innovations in crop improvement. For rapeseed, the path from laboratory marker to a saline-alkali-tolerant cultivar standing in a rehabilitated field just became considerably shorter.
Subject of Research: Development of molecular markers and a 5K cGPS genotyping chip associated with saline-alkali tolerance in rapeseed (Brassica napus L.) for marker-assisted selection and molecular design breeding
Subject of Research: Agriculture
Article Title: Development of molecular markers associated with saline-alkali tolerance in rapeseed (Brassica napus L.)
Article References: Hou, X., Liu, F., Li, O., Ge, X., He, C., Hu, C., Jiang, R., Chen, J., Zou, M., Jia, D., Li, Q., Miao, H., Wen, J., Zhao, L., Wan, H., Fu, T., Gu, Y., & Shen, J. (2026). Development of molecular markers associated with saline-alkali tolerance in rapeseed (Brassica napus L.). Theoretical and Applied Genetics, 139(10), Article 264. https://doi.org/10.1007/s00122-026-05376-6
Image Credits: AI Generated
DOI: 10.1007/s00122-026-05376-6
Keywords: rapeseed, Brassica napus, saline-alkali tolerance, molecular markers, KASP markers, InDel markers, cGPS genotyping chip, marker-assisted selection, candidate gene association analysis, haplotypes, molecular design breeding, soil salinization
Cite Scienmag News
APA MLA Chicago
Alan Morgan. (September 10, 2026). New molecular markers developed for saline-alkali tolerance in rapeseed. Scienmag. https://scienmag.com/new-molecular-markers-developed-for-saline-alkali-tolerance-in-rapeseed/
Alan Morgan. “New molecular markers developed for saline-alkali tolerance in rapeseed.” Scienmag, 10 September 2026, https://scienmag.com/new-molecular-markers-developed-for-saline-alkali-tolerance-in-rapeseed/. Accessed 10 September 2026.
Alan Morgan. “New molecular markers developed for saline-alkali tolerance in rapeseed.” Scienmag. September 10, 2026. https://scienmag.com/new-molecular-markers-developed-for-saline-alkali-tolerance-in-rapeseed/
Copy citation Download RIS
Tags: advancements in plant genomics for salt stressbreedingbreeding for salt-tolerant cropsbreeding salt-tolerant rapeseed varietiesgenetic engineering for saline-alkali resiliencegenetic markers for salt-stress resiliencegenotyping chip for plant breedinggenotyping chips for plant breedingglobal soil salinization and crop adaptationimpact of climate change on soil salinitymolecular breeding tools for saline soilsmolecular markers for salt tolerancemolecular markers for salt-alkali soil adaptationmolecular tools for saline-alkali soil toleranceplant genetics for saline-alkali stressplant stress tolerance indicatorsrapeseed genetic improvementrapid seedling screening for salt toleranceSaline-alkali soil tolerance in cropsSaline-alkali tolerance in rapeseedsaline-alkali tolerance traits in cropssalt-affected land reclamationsalt-affected soils impact on agriculturesoil salinization and agriculture
