Department of Genetics and Plant Breeding, S.V. Agricultural College, Acharya NG Ranga Agricultural University (ANGRAU), Tirupati, 517502, Andhra Pradesh, India.
Department of Molecular Biology and Biotechnology, S.V. Agricultural College, Acharya NG Ranga Agricultural University (ANGRAU), Tirupati, 517502, Andhra Pradesh, India.
Mol Biol Rep. 2023 Feb;50(2):1499-1515. doi: 10.1007/s11033-022-08153-y. Epub 2022 Dec 12.
Rice crop is damaged extremely by abiotic stress world-wide. The best approach to enhance drought tolerance in rice varieties is to identify and introgress yield QTLs with major effects. The Association mapping approach helps in the identification of genomic regions governing physiological, yield and yield attributes under moisture and heat stress conditions in diverse collections of crop germplasm, based on historic recombination events and linkage disequilibrium across the genome.
The association mapping panel of 110 rice germplasm lines exhibited significant variation for all the traits in both irrigated and moisture stress conditions. The extent of yield reduction ranged to 83% during rabi, 2018-19, 53% in rabi, 2019-20 and 68% in pooled analysis. The genotypes Badami, Badshabhog, Pankaj, Varalu, Vasundhara, Vivekdhan, Krishna and Minghui63 exhibited drought tolerance with least yield penalty under moisture stress conditions. The genotypes Konark, MTU3626, NLR33671, PR118 and Triguna exhibited minimal reduction in heat stress tolerance traits. Association mapping of germplasm using 37808 SNP markers detected a total of 10 major MTA (Marker-trait association) clusters distributed on chromosomes 1, 3, 4 and 11 through mixed linear model (MLM) governing multiple traits from individual data analysis which are consistent across the years and situations. The pooled data generated a total of five MTA clusters located on chromosome 6. In addition, several novel unique MTAs were also identified. Heat stress analysis generated a total of 23 MTAs distributed on chromosomes 1, 5, 6 and 11. Candidate gene analysis detected a total of 53 and 38 genes under individual and pooled data analysis for various yield and yield attributes under control and moisture stress conditions, respectively and a total of 11 candidate genes in heat stress Conditions.
The major and novel MTAs identified in the present investigation for various drought and heat tolerant traits can be utilized for breeding climate-resilient rice varieties. The candidate genes predicted for key MTAs are of great value to deploy into the rice breeding after functional characterization.
水稻作物在全球范围内受到非生物胁迫的严重破坏。提高水稻品种耐旱性的最佳方法是鉴定和导入具有主要效应的产量 QTL。关联作图方法有助于根据历史重组事件和整个基因组的连锁不平衡，在不同作物种质资源的集合中鉴定在水分和热胁迫条件下控制生理、产量和产量性状的基因组区域。
110 个水稻种质品系的关联作图群体在灌溉和水分胁迫条件下所有性状均表现出显著差异。在 2018-19 年拉比季，产量降低幅度高达 83%，在 2019-20 年拉比季，产量降低幅度为 53%，在汇总分析中，产量降低幅度为 68%。在水分胁迫条件下，基因型 Badami、Badshabhog、Pankaj、Varalu、Vasundhara、Vivekdhan、Krishna 和 Minghui63 表现出耐旱性，产量损失最小。基因型 Konark、MTU3626、NLR33671、PR118 和 Triguna 表现出最小的耐热性性状降低。利用 37808 个 SNP 标记对种质进行关联作图，通过混合线性模型（MLM）检测到总共 10 个主要 MTA（标记-性状关联）簇，分布在染色体 1、3、4 和 11 上，该模型可对个体数据分析中的多个性状进行管理，这些性状在各年和情况下都是一致的。汇总数据共产生了 5 个位于染色体 6 上的 MTA 簇。此外，还鉴定了一些新的独特的 MTAs。热应激分析共产生了 23 个位于染色体 1、5、6 和 11 上的 MTAs。在个体和汇总数据分析中，候选基因分析分别检测到控制和水分胁迫条件下各种产量和产量性状的 53 个和 38 个基因，以及热应激条件下的 11 个候选基因。
本研究鉴定的各种耐旱和耐热性状的主要和新的 MTAs 可用于培育耐气候水稻品种。对关键 MTAs 预测的候选基因在功能表征后对水稻育种具有重要价值。
