Exploring Chromosomes segment substitution lines from inter-specific crosses to decipher the genetics of grain weight in rice.

Wild introgression lines (ILs) derived from interspecific crosses between the Oryza sativa mega variety Swarna and Oryza nivara accession, exhibiting significant phenotypic divergence for thousand grain weight (TGW), were subjected to quantitative trait locus sequencing (QTL-seq) to delineate the genomic regions and sequence variations underlying this trait. DNA from individuals with contrasting TGW phenotypes was pooled into high- and low-TGW bulks, followed by whole-genome resequencing to generate high-depth sequence data on Illumina platform. SNP-index and delta SNP-index analyses were performed to identify candidate genomic regions associated with TGW, leveraging statistical thresholds to pinpoint significant QTLs. High-confidence SNPs and InDels within these regions will be characterized to identify putative functional variants linked to grain weight variation, providing novel insights into the genetic determinants of TGW in interspecific rice derivatives.

野生渐渗系（introgression lines, ILs）由栽培稻（Oryza sativa）主推品种Swarna与尼瓦拉野生稻（Oryza nivara）种质材料的种间杂交获得，该群体的千粒重（thousand grain weight, TGW）表型存在显著分化。本研究对该群体开展数量性状位点测序（quantitative trait locus sequencing, QTL-seq），以解析调控千粒重性状的基因组区域与序列变异基础。研究人员提取千粒重表型极端差异的单株DNA，分别混合构建高千粒重与低千粒重混池，随后通过全基因组重测序在Illumina测序平台上获取高深度测序数据。通过开展SNP-index与ΔSNP-index分析，结合统计阈值精准定位与千粒重相关的候选基因组区域，进而鉴定出显著的数量性状位点（quantitative trait locus, QTL）。后续将对这些区域内的高可信度单核苷酸多态性（single nucleotide polymorphism, SNPs）与插入缺失（insertion-deletion, InDels）进行特征分析，以筛选与粒重变异相关的潜在功能变异位点，为种间水稻杂交衍生群体千粒重的遗传决定因子提供全新的研究见解。