Pandit Elssa, Tasleem Swaleha, Barik Saumya R, Mohanty Durga P, Nayak Deepak K, Mohanty Shakti P, Das Sujata, Pradhan Sharat K
Crop Improvement Division, Central Rice Research Institute (ICAR)Cuttack, India.
Front Plant Sci. 2017 Apr 25;8:552. doi: 10.3389/fpls.2017.00552. eCollection 2017.
Rice crop is sensitive to cold stress at seedling stage. A panel of population representing 304 shortlisted germplasm lines was studied for seedling stage chilling tolerance in rice. Six phenotypic classes were exposed to six low temperature stress regimes under control phenotyping facility to investigate response pattern. A panel of 66 genotypes representing all phenotypic classes was used for ensuring genetic diversity, population structure and association mapping for the trait using 58 simple sequence repeat (SSR) and 2 direct trait linked markers. A moderate level of genetic diversity was detected in the panel population for the trait. Deviation of Hardy-Weinberg's expectation was detected in the studied population using Wright's F statistic. The panel showed 30% variation among population and 70% among individuals. The entire population was categorized into three sub-populations through STRUCTURE analysis. This revealed tolerance for the trait had a common primary ancestor for each sub-population with few admix individuals. The panel population showed the presence of many QTLs for cold stress tolerance in the individuals representing like genome-wide expression of the trait. Nineteen SSR markers were significantly associated at chilling stress of 8°C to 4°C for 7-21 days duration. Thus, the primers linked to the seedling stage cold tolerance QTLs namely qCTS9, qCTS-2, qCTS6.1, qSCT2, qSCT11, qSCT1a, qCTS-3.1, qCTS11.1, qCTS12.1, qCTS-1b, and CTB2 need to be pyramided for development of strongly chilling tolerant variety.
水稻作物在幼苗期对冷胁迫敏感。研究了一组代表304个入围种质系的群体在水稻幼苗期的耐冷性。在可控表型设施下，将六个表型类别暴露于六种低温胁迫条件下，以研究其反应模式。使用66个代表所有表型类别的基因型群体，通过58个简单序列重复（SSR）标记和2个直接性状连锁标记来确保该性状的遗传多样性、群体结构和关联图谱分析。在该群体中检测到该性状的遗传多样性处于中等水平。使用赖特F统计量在研究群体中检测到哈迪-温伯格期望的偏差。该群体显示群体间变异为30%，个体间变异为70%。通过STRUCTURE分析将整个群体分为三个亚群体。这表明该性状的耐受性在每个亚群体中有一个共同的主要祖先，只有少数混合个体。该群体在代表该性状全基因组表达的个体中显示出许多耐冷胁迫的数量性状位点（QTL）。19个SSR标记在8℃至4℃的冷胁迫下持续7至21天与该性状显著相关。因此，与幼苗期耐冷QTL即qCTS9、qCTS - 2、qCTS6.1、qSCT2、qSCT11、qSCT1a、qCTS - 3.1、qCTS11.1、qCTS12.1、qCTS - 1b和CTB2连锁的引物需要聚合，以培育强耐冷品种。
