BACKGROUND Triticum aestivum (wheat) is one of the world's oldest crops and has been used for >8000 years as a food crop in North Africa, West Asia and Europe. Today, wheat is one of the most important sources of grain for humans, and is cultivated on greater areas of land than any other crop. As the human population increases and soil salinity becomes more prevalent, there is increased pressure on wheat breeders to develop salt-tolerant varieties in order to meet growing demands for yield and grain quality. Here we developed a mutant wheat population using the moderately salt-tolerant Bangladeshi variety BARI Gom-25, with the primary goal of further increasing salt tolerance. RESULTS After titrating the optimal ethyl methanesulfonate (EMS) concentration, ca 30,000 seeds were treated with 1% EMS, and 1676 lines, all originating from single seeds, survived through the first four generations. Most mutagenized lines showed a similar phenotype to BARI Gom-25, although visual differences such as dwarfing, giant plants, early and late flowering and altered leaf morphology were seen in some lines. By developing an assay for salt tolerance, and by screening the mutagenized population, we identified 70 lines exhibiting increased salt tolerance. The selected lines typically showed a 70% germination rate on filter paper soaked in 200 mM NaCl, compared to 0-30% for BARI Gom-25. From two of the salt-tolerant OlsAro lines (OA42 and OA70), genomic DNA was sequenced to 15x times coverage. A comparative analysis against the BARI Gom-25 genomic sequence identified a total of 683,201 (OA42), and 768,954 (OA70) SNPs distributed throughout the three sub-genomes (A, B and D). The mutation frequency was determined to be approximately one per 20,000 bp. All the 70 selected salt-tolerant lines were tested for root growth in the laboratory, and under saline field conditions in Bangladesh. The results showed that all the lines selected for tolerance showed a better salt tolerance phenotype than both BARI Gom-25 and other local wheat varieties tested. CONCLUSION The mutant wheat population developed here will be a valuable resource in the development of novel salt-tolerant varieties for the benefit of saline farming.

中文翻译：

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EMS诱变小麦群体的开发和鉴定以及耐盐小麦品系的鉴定。

背景技术普通小麦（小麦）是世界上最古老的作物之一，并且在北非，西亚和欧洲已经用作粮食作物超过8000年。如今，小麦已成为人类最重要的谷物来源之一，并且在比任何其他作物更大的土地上耕种。随着人口的增加和土壤盐碱化的日益普遍，小麦育种者面临开发耐盐品种的压力越来越大，以满足对产量和谷物品质日益增长的需求。在这里，我们使用中等耐盐性孟加拉国品种BARI Gom-25开发了一个突变小麦种群，其主要目标是进一步提高耐盐性。结果滴定最佳甲磺酸乙酯（EMS）浓度后，用1％EMS和1676个品系处理了约30,000个种子。全部起源于单一种子，幸存了前四代。大多数诱变品系表现出与BARI Gom-25相似的表型，尽管在某些品系中发现了视觉差异，如矮化，巨型植物，早花和晚花以及叶片形态发生了变化。通过开发耐盐性测定方法，并筛选诱变的种群，我们鉴定出70个品系表现出更高的耐盐性。选定的品系通常在浸有200 mM NaCl的滤纸上显示出70％的发芽率，而BARI Gom-25则为0-30％。从两个耐盐的OlsAro品系（OA42和OA70），对基因组DNA进行测序，其覆盖率是其15倍。对BARI Gom-25基因组序列的比较分析确定了分布在三个亚基因组（A，B和D）中的总共683,201（OA42）和768,954（OA70）SNP。确定突变频率约为每20,000 bp 1个。在孟加拉国和盐田条件下，在实验室中测试了所有70个选定的耐盐品系的根系生长。结果表明，所有选择用于耐性的品系均表现出比BARI Gom-25和其他当地小麦品种更好的耐盐性表型。结论这里开发的突变小麦种群将是开发新的耐盐品种的宝贵资源，有利于盐碱农业。结果表明，所有选择用于耐性的品系均表现出比BARI Gom-25和其他当地小麦品种更好的耐盐性表型。结论这里开发的突变小麦种群将是开发新的耐盐品种的宝贵资源，有利于盐碱农业。结果表明，所有选择用于耐性的品系均表现出比BARI Gom-25和其他当地小麦品种更好的耐盐性表型。结论这里开发的突变小麦种群将是开发新的耐盐品种的宝贵资源，有利于盐碱农业。