PDF(Pubmed)
Abstract：
Rice remains a major staple food source for the rapidly growing world population. However, regular occurrences of carcinogenic arsenic (As) minerals in waterlogged paddy topsoil pose a great threat to rice production and consumers across the globe. Although As contamination in rice has been well recognized over the past two decades, no suitable rice germplasm had been identified to exploit in adaptive breeding programs. Therefore, this current study identified suitable rice germplasm for As tolerance and exclusion based on a variety of traits and investigated the interlinkages of favorable traits during different growth stages. Fifty-three different genotypes were systematically evaluated for As tolerance and accumulation. A germination screening assay was carried out to identify the ability of individual germplasm to germinate under varying As stress. Seedling-stage screening was conducted in hydroponics under varying As stress to identify tolerant and excluder genotypes, and a field experiment was carried out to identify genotypes accumulating less As in grain. Irrespective of the rice genotypes, plant health declined significantly with increasing As in the treatment. However, genotype-dependent variation in germination, tolerance, and As accumulation was observed among the genotypes. Some genotypes (WTR1-BRRI dhan69, NPT-IR68552-55-3-2, OM997, and GSR IR1-5-Y4-S1-Y1) showed high tolerance by excluding As in the shoot system. Arsenic content in grain ranged from 0.12 mg kg-1 in Huang-Hua-Zhan (indica) from China to 0.48 mg kg-1 in IRAT 109 (japonica) from Brazil. This current study provides novel insights into the performance of rice genotypes under varying As stress during different growth stages for further use in ongoing breeding programs for the development of As-excluding rice varieties for As-polluted environments.
摘要：
大米仍然是快速增长的世界人口的主要主食来源。然而,淹水水稻表层土壤中经常发生的致癌砷（As）矿物质对全球水稻生产和消费者构成了巨大威胁。尽管在过去的二十年里，水稻中的污染已经得到了很好的认识，尚未确定合适的水稻种质可用于适应性育种计划。因此,本研究根据各种性状鉴定了水稻种质的As耐受性和排除性，并研究了不同生长阶段有利性状的相互联系。系统地评估了53种不同基因型的As耐受性和积累。进行发芽筛选测定以鉴定个体种质在变化的As胁迫下发芽的能力。在不同的As胁迫下在水培中进行苗期筛选，以鉴定耐受性和排除性基因型，并进行了田间试验，以鉴定在谷物中积累较少As的基因型。不考虑水稻基因型，随着处理中As的增加，植物健康状况显着下降。然而,发芽中的基因型依赖性变异，容忍度,在基因型之间观察到As积累。某些基因型（WTR1-BRRIdhan69，NPT-IR68552-55-3-2，OM997和GSRIR1-5-Y4-S1-Y1）通过在芽系统中排除As而表现出高耐受性。谷物中的砷含量范围从中国的黄华詹中的0.12mgkg-1到巴西的IRAT109中的0.48mgkg-1。本研究为水稻基因型在不同生长阶段的不同As胁迫下的表现提供了新的见解，可进一步用于正在进行的育种计划，以开发As污染环境中的As排除水稻品种。
