Plant Breeding Division, International Rice Research Institute (IRRI), DAPO Box, 7777, Metro, Manila, Philippines.
Plant Biotechnology Center, Department of Agriculture, Shwe Nanthar, Mingaladon Tsp, Yangon, Myanmar.
Sci Rep. 2019 Dec 20;9(1):19605. doi: 10.1038/s41598-019-55357-7.
Identification of Quantitative Trait Loci (QTL) has been a challenge for complex traits due to the use of populations with narrow genetic base. Most of QTL mapping studies were carried out from crosses made within the subspecies, either indica × indica or japonica × japonica. In this study we report advantages of using Multi-parent Advanced Generation Inter-Crosses global population, derived from a combination of eight indica and eight japonica elite parents, in QTL discovery for yield and grain quality traits. Genome-wide association study and interval mapping identified 38 and 34 QTLs whereas Bayesian networking detected 60 QTLs with 22 marker-marker associations, 32 trait-trait associations and 65 marker-trait associations. Notably, nine known QTLs/genes qPH/OsGA20ox2, qDF/OsMADS50, PL, QDg1, qGW-5b, grb7-2, qGL/GS3, Amy6/Wx gene and OsNAS3 were consistently identified by all approaches for nine traits whereas qDF/OsMADS50 was co-located for both yield and days-to-flowering traits on chromosome 3. Moreover, we identified a number of candidate QTLs in either one or two analyses but further validations will be needed. The results indicate that this new population has enabled identifications of significant QTLs and interactions for 16 traits through multiple approaches. Pyramided recombinant inbred lines provide a valuable source for integration into future breeding programs.
由于使用遗传基础狭窄的群体，因此鉴定数量性状基因座（QTL）一直是复杂性状的挑战。大多数 QTL 作图研究都是在亚种内进行的杂交，即籼稻×籼稻或粳稻×粳稻。在这项研究中，我们报告了利用多亲本高级世代互交全球群体的优势，该群体源自 8 个籼稻和 8 个粳稻优良亲本的组合，用于产量和谷物品质性状的 QTL 发现。全基因组关联研究和区间作图鉴定了 38 个和 34 个 QTL，而贝叶斯网络检测到 60 个 QTL，其中有 22 个标记-标记关联、32 个性状-性状关联和 65 个标记-性状关联。值得注意的是，通过所有方法都一致鉴定出了 9 个已知的 QTL/基因 qPH/OsGA20ox2、qDF/OsMADS50、PL、QDg1、qGW-5b、grb7-2、qGL/GS3、Amy6/Wx 基因和 OsNAS3，这些基因与 9 个性状有关，而 qDF/OsMADS50 则位于第 3 号染色体上与产量和开花天数有关的两个性状上。此外，我们在一个或两个分析中鉴定出了一些候选 QTL，但还需要进一步验证。结果表明，通过多种方法，这种新群体已经能够鉴定出 16 个性状的重要 QTL 和互作。级联重组自交系为整合到未来的育种计划中提供了有价值的资源。
