水稻分蘖期耐盐性鉴定评价方法确立及种质筛选

分蘖期是水稻由秧田生长向本田生长过渡的营养生长关键时期。在盐渍化土壤上种植水稻,分蘖期耐盐性对水稻能否正常生长至关重要。合适的耐盐性鉴定方法是水稻耐盐种质筛选的前提。本研究目的在于通过水稻分蘖期盐浓度梯度筛选试验,明确水稻分蘖期耐盐性鉴定最适盐胁迫浓度和调查时间;利用确立的鉴定方法,筛选出水稻分蘖期耐盐种质。本研究选取具有不同程度耐盐性的26份水稻品种,于2015年和2016年分别在10个和7个盐浓度梯度下,以盐害等级为分蘖期耐盐评价指标,开展水稻分蘖期耐盐性鉴定评价试验。结果表明,在0.5%盐浓度下,处理4~6周后供试种质的盐害等级差异表现为最大,因此认为0.5%盐浓度是水稻分蘖期耐盐性鉴定的最适盐胁迫浓度,盐处理后4~6周是水稻分蘖期盐害等级调查的最佳调查时间。参照国际水稻所提出的水稻分蘖期耐盐性评价标准,本研究对其进行了改进,提出以单株为单位进行水稻分蘖期耐盐性评价方法,利用平均盐害等级评估分蘖期耐盐性。该方法能够方便、准确地评价水稻耐盐性强弱。依据上述确立的水稻分蘖期耐盐性鉴定评价方法,本研究于2017-2019年期间对2886份来自不同生态区域的水稻种质进行分蘖期耐盐性鉴定评价,鉴定筛选出137份耐盐种质,为水稻耐盐遗传机制和育种研究提供资源支撑。

Establishment of an Updated Assay for Testing Salt Tolerance at the Tillering Stage of Rice and Germplasm Screening

The tillering stage is the key period for the transition of rice from nursey to paddy. The salt tolerance at the tillering stage becomes of importance when planting rice in salinized soil. Establishment of an optimal strategy is thus of interest in order to identify the rice germplasms that show salt tolerant. This study attempted to determine the optimal salt concentration and the duration of treatment at the tillering stage. By using 26 rice varieties with the levels of salt tolerance,we conducted the experiments with the gradients of salt concentration(10 and 7 in 2015 and 2016,respectively). The salt injury score was deployed as an index for evaluating salt tolerance at the tillering stage. The results showed that,when applied with the salt concentration of 0.5%,salt injury score between varieties showed the largest difference after salt treatment about 4-6 weeks. This pipeline was considered to be optimal in order to examine for rice salt tolerance. On the contrast to the evaluation standard of salt tolerance of rice at the tillering stage that was proposed by international rice research institute(IRRI),this study proposed a updated method for evaluating the salt tolerance of rice at the tillering stage,especially by using a single plant as a unit and deploying the average salt injury score to evaluate the salt tolerance. By taking use of the aforementioned pipeline,this study carried out a three-year evaluation(2017 to 2019) in 2886 rice accessions that were collected from different ecological regions. As a result,137 rice accessions showing salt-tolerant were identified,which might provide elite resource to support the genetic improvement and breeding research for rice salt tolerance.