镉低积累水稻亲本及其杂交组合镉积累特征分析

为培育镉(Cd)安全水稻品种,以Cd低积累水稻亲本雅恢2816及其4个杂交组合泸98A/雅恢2816、5406A/雅恢2816、C268A/雅恢2816、蓉18A/雅恢2816为研究对象,采用盆栽试验,分析Cd低积累水稻亲本及其杂交后代成熟期Cd积累分配特征,探讨亲本及杂交组合对Cd的吸收转运差异。结果表明:在Cd处理浓度为1、2、4 mg·kg~(-1)条件下,杂交组合生物量均显著高于亲本,超亲优势达21.86%~89.63%。不同浓度Cd处理下,亲本及杂交组合各器官Cd含量分配顺序均为根茎、叶穗,其中杂交组合5406A/雅恢2816和C268A/雅恢2816的穗部Cd含量显著低于亲本,糙米Cd含量也仅为亲本的57.14%~86.36%,低于食品安全国家标准0.2 mg·kg~(-1)。随Cd处理浓度的增加,亲本及杂交组合Cd由根系向地上部的转移系数均降低,杂交后Cd在根系的分配比例上升,杂交组合根系Cd积累量为亲本的1.49~3.24倍,而茎、叶的分配比例仅为亲本的72.06%~81.20%和74.18%~91.08%。杂交组合5406A/雅恢2816和C268A/雅恢2816表现出优于亲本的籽粒Cd低积累特征,具有在中、轻度污染土壤上安全生产的潜力。

Characteristics of cadmium accumulation in low cadmium-accumulating rice parent and its hybrids

A pot culture experiment was conducted to investigate the characteristics of cadmium(Cd) accumulation, distribution and transport in a low Cd-accumulating rice parent(YaHui2816) and its hybrids(Lu98A/YaHui2816, 5406A/YaHui2816, C268A/YaHui2816, and Rong18A/YaHui2816) in order to select Cd pollution-safe breeding materials. The biomass of the hybrids was significantly higher than that of the parent, which was 21.86%~89.63% greater under 1 to 4 mg·kg^-1 Cd treatments. The Cd content in roots, stems and leaves increased as soil Cd concentrations increased. The Cd content in different tissues of the rice parent and its hybrids were in sequence of root > stem, leaf >> ear. The Cd content in ears of 5406A/YaHui2816 and C268A/YaHui2816 was significantly lower than that of the other hybrid combinations, and Cd in their brown rice was only 57.14%~86.36% of that of the rice parent, which was lower than the National Food Safety Standard(0.2 mg·kg^-1). The root-shoot translocation factors of Cd in the rice parent and its hybrids were significant decreased when soil Cd increased. The distribution of Cd in different parts of the rice parent was in order of stem > root > leaf > ear, whereas that order was root > stem > leaf > ear in the hybrids. The Cd accumulation in roots of the hybrids was 1.49~3.24 times higher than that of the parent. In conclusion, brown rice Cd content was lower in 5406A/YaHui2816 and C268A/YaHui2816 than in the low Cd-accumulative rice parent, and could be used as potential Cd pollution-safe materials to grow in medium to low Cd-polluted farmland.