Background

Reproductive-stage drought stress is a major impediment to rice production in rainfed areas. Conventional and marker-assisted breeding strategies for developing drought-tolerant rice varieties are being optimized by mining and exploiting adaptive traits, genetic diversity; identifying the alleles, and understanding their interactions with genetic backgrounds for their increased contribution to drought tolerance. Field experiments were conducted in this study to identify marker-trait associations (MTAs) involved in response to yield under reproductive-stage (RS) drought. A diverse set of 280 indica-aus accessions was phenotyped for ten agronomic traits including yield and yield-related traits under normal irrigated condition and under two managed reproductive-stage drought environments. The accessions were genotyped with 215,250 single nucleotide polymorphism markers.

Results

The study identified a total of 219 significant MTAs for 10 traits and candidate gene analysis within a 200 kb window centred from GWAS identified SNP peaks detected these MTAs within/ in close proximity to 38 genes, 4 earlier reported major grain yield QTLs and 6 novel QTLs for 7 traits out of the 10. The significant MTAs were mainly located on chromosomes 1, 2, 5, 6, 9, 11 and 12 and the percent phenotypic variance captured for these traits ranged from 5 to 88%. The significant positive correlation of grain yield with yield-related and other agronomic traits except for flowering time, observed under different environments point towards their contribution in improving rice yield under drought. Seven promising accessions were identified for use in future genomics-assisted breeding programs targeting grain yield improvement under drought.

Conclusion

These results provide a promising insight into the complex genetic architecture of grain yield under reproductive-stage drought in different environments. Validation of major genomic regions reported in the study will enable their effectiveness to develop drought-tolerant varieties following marker-assisted selection as well as to identify genes and understanding the associated physiological mechanisms.

中文翻译：

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不同in稻群体中生殖阶段干旱下产量和产量相关性状的全基因组关联研究。

背景

生育期干旱胁迫是雨育地区水稻生产的主要障碍。通过挖掘和利用适应性状，遗传多样性，正在优化开发耐旱水稻品种的常规和标记辅助育种策略；鉴定等位基因，并了解它们与遗传背景的相互作用，以提高对耐旱性的贡献。在这项研究中进行了田间试验，以鉴定在生育期（RS）干旱下参与产量响应的标记性状关联（MTA）。280套印度in在正常灌溉条件下和两个有管理的生殖期干旱环境下，对10个农艺性状（包括产量和与产量相关的性状）进行了表型鉴定。用215,250个单核苷酸多态性标记对这些种进行基因分型。

结果

该研究共鉴定了219个10个性状的重要MTA，并在以GWAS为中心的200 kb窗口内进行了候选基因分析，确定了在38个基因内/附近检测到这些MTA的SNP峰，4个较早报道的主要谷物产量QTL和6个新QTL在10个特征中有7个特征。显着的MTA主要位于1、2、5、6、9、11和12号染色体上，这些特征捕获的表型变异百分比为5％至88％。在不同环境下观察到，除开花时间外，谷物产量与产量相关及其他农艺性状的显着正相关，表明它们在干旱条件下对提高水稻产量的贡献。确定了七个有前途的种质，可用于未来的基因组学辅助育种计划，以提高干旱条件下的谷物产量。

结论

这些结果为生殖阶段干旱在不同环境下谷物产量的复杂遗传结构提供了有前途的见识。这项研究中报告的主要基因组区域的验证将使它们能够在标记辅助选择下开发耐旱品种，以及鉴定基因并了解相关的生理机制。