Epistatic QTL for yield heterosis in tomato

Controlled population development and genome-wide association studies have proven powerful in uncovering genes and alleles underlying complex traits. An underexplored dimension of such studies is the phenotypic contribution of non-additive interactions between quantitative trait loci (QTL). Capturing such epistasis in a genome-wide manner requires very large populations to represent replicated combinations of loci whose interactions determine phenotypic outcomes. Here, we dissect epistasis using a densely genotyped population of 1400 backcross-inbred lines (BILs) between a modern processing tomato inbred (Solanum lycopersicum) and the Lost Accession of a distant, green-fruited, drought-tolerant wild species, Solanum pennellii. The homozygous BILs, each representing an average of 11 introgressions, and their hybrids with the recurrent parents were phenotyped for tomato yield components. Population-wide mean yield of the BILs was less than 50% of that of their hybrids (BILH), and correspo...

受控种群构建与全基因组关联研究（genome-wide association studies）已被证实可有效解析复杂性状背后的基因与等位基因。此类研究中尚有一个未被充分探索的维度，即数量性状基因座（quantitative trait loci, QTL）间非加性互作的表型贡献。以全基因组尺度解析此类上位性，需要借助规模极大的种群以复现那些互作决定表型结果的基因座组合。本研究利用1400个经高密度基因分型的回交自交系（backcross-inbred lines, BILs）群体解析上位性，该群体由现代加工用番茄自交系（栽培番茄Solanum lycopersicum）与远缘绿果、耐旱的野生种潘那利番茄（Solanum pennellii）的稀有保藏种质（Lost Accession）构建而成。每个纯合回交自交系平均携带11个渐渗片段，本研究同时对这些回交自交系及其与轮回亲本的杂交种开展了番茄产量构成性状的表型鉴定。回交自交系的种群平均产量仅为其杂交种（BILH）的50%以下，且对应……