不同地理来源粳稻种质资源的耐碱性表型差异OA

To investigate the effects of alkaline stress on leaf injury and seedling survival of japonica rice,and to clarify differences in alkaline tolerance among varieties from different geographic origins,a total of 437 japonica rice germplasm resources were evaluated for alkaline tolerance in an alkaline screening pool with a pH value of approximately 8.9 during 2016-2017,with repeated assessments conducted over two consecutive years.The dead leaf rate and dead seedling rate at the seedling stage were used as the primary indicators of alkaline tolerance.The results showed that both the dead leaf rate and dead seedling rate gradually increased with prolonged alkaline stress,and significant differences in alkaline tolerance were observed among different japonica varieties.The period of 15-25 days after alkaline stress treatment was identified as the critical stage for evaluating alkaline tolerance at the seedling stage,with higher phenotypic values,standard deviation,and coefficient of variation for dead leaf rate observed at 15 days,while those of dead seedling rate were higher at 25 days.Population-level analysis revealed a regional clustering pattern of alkaline tolerance.The dead leaf rates of materials from Heilongjiang and Jilin provinces in the Northeastern rice-growing region of China were 55.45％and 55.04％,respectively,and their dead seedling rates were 28.79％and 26.19％,respectively,indicating stronger alkaline tolerance at the seedling stage.Additionally,20 alkaline-tolerant japonica rice germplasm accessions,including Kongyu 131 and Jijing 105,were identified using a two-year mean dead seedling rate≤13.33％and dead leaf rate≤45.66％as the screening criteria,providing valuable genetic resources for the improvement of japonica rice varieties adapted to saline-alkaline soils.