State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, China.
Zhenjiang Institute of Agricultural Sciences in Hilly Region of Jiangsu Province, Jurong, 212400, China.
Theor Appl Genet. 2020 Dec;133(12):3287-3297. doi: 10.1007/s00122-020-03669-y. Epub 2020 Aug 27.
Heterosis QTLs, including qSS7 and qHD8, with dominance effects were identified through GBS and large-scale phenotyping of CSSLs and hybrid F populations in a paddy field. Heterosis has contributed immensely to agricultural production, but its genetic basis is unclear. We evaluated dominance effects by creating two hybrid populations: a B-homo set with a homozygous background and heterozygous chromosomal segments and a B-heter set with a heterozygous background and homozygous segments. This was achieved by crossing a set of 156 backcrossed-derived chromosome segment substitution lines (CSSLs) with their recurrent parent (9311), the male parent of the first super-high-yield hybrid Liangyoupei9 (LYP9), and with the female parent (PA64s) of the hybrid. The CSSLs were subjected to a genotyping-by-sequencing analysis to develop a genetic map of segments introduced from the PA64s. We evaluated the heterotic effects on eight yield-related traits in the hybrid variety and F populations in large-scale field experiments over 2 years. Using a linkage map consisting of high-density SNPs, we identified heterosis-associated genes in LYP9. Five candidate genes contributed to the high yield of LYP9, with qSS7 and qHD8 repeatedly detected in both B-hybrid populations. The heterozygous segments harboring qSS7 and qHD8 showed dominance effects that contributed to the heterosis of yield components in the hybrid rice variety Liangyoupei9.
通过对 CSSL 和杂交 F1 群体进行 GBS 和大规模表型分析，在水田中鉴定到具有显性效应的杂种优势 QTL，包括 qSS7 和 qHD8。杂种优势对农业生产有巨大贡献，但它的遗传基础尚不清楚。我们通过创建两个杂交群体来评估显性效应：一个是 B-homo 群体，具有纯合背景和杂合染色体片段；另一个是 B-heter 群体，具有杂合背景和纯合片段。这是通过将一组 156 个回交衍生的染色体片段替换系（CSSL）与它们的轮回亲本（9311）、第一个超高产杂交水稻两优培九（LYP9）的父本以及杂交的母本（PA64s）进行杂交来实现的。对 CSSL 进行了基于测序的基因型分析，以开发来自 PA64s 的片段的遗传图谱。我们在两年的大规模田间试验中评估了杂种品种和 F1 群体中八个与产量相关的性状的杂种优势效应。使用由高密度 SNP 组成的连锁图谱，我们在 LYP9 中鉴定到与杂种优势相关的基因。五个候选基因对 LYP9 的高产有贡献，qSS7 和 qHD8 在两个 B-杂种群体中都被重复检测到。携带 qSS7 和 qHD8 的杂合片段表现出显性效应，这对杂交水稻品种两优培九的产量构成杂种优势有贡献。
