Salt tolerance evaluation for core collection of rice landraces in Guangxi

ObjectiveStrong salt tolerant cultivated rice germplasm resources were screened in order to provide varieties for reclamation of saline and alkaline land, and offer reference for salt tolerant variety breeding and salt tolerant genes exploration. MethodSalt tolerance at germination stage and seedling stage of rice were identified using 419 rice core germplasm resources in Guangxi. At germination stage, salt stress was conducted with 1.5% NaCl solution and relative salt injury rate was used as evaluation index. At seedling stage, seedlings were cultured in sand and treated with 0.5% NaCl solution, with dead leaf rate as evaluation index and plant dwarfing rate as reference index. ResultIn Guangxi, salt tolerance grade at rice germination stage was 3.77, and most rice germplasm resources were classified in grade 1 and 3, accounting for 62.53% of the total. Salt tolerance grade at rice seedling stage was 7.15, and most rice germplasm resources were classified in grade 7 and 9, which accounted for 75.89%. In comparison of salt tolerance for different rice landraces, at germination stage, average salt tolerance of indica(3.64) was higher than that of japonica(4.28), and the coefficient of variation of indica rice(69.12) was higher than japonica rice(60.28). At seedling stage, average salt tolerance of indica (6.91) was higher than that of japonica (8.03), and coefficient of variation of indica (30.21) was higher than that of japonica(18.43). At seedling stage, plant dwarfing rate(32.73) and coefficient of variation(50.92) of indica was less than those of japonica (plant dwarfing rate 37.22 and coefficient of variation 63.62).Correlation analysis showed that for both indica (r=0.0667) and japonica (r=0.0531), salt tolerance grades at germination stage and seeding stage were not significantly correlated(P>0.05). In terms of salt tolerance in different rice planting regions, the average salt tolerance at germination stage(3.48) and the seedling stage (6.97) in Guangxi southern region were the highest among four rice planting regions. ConclusionSalt tolerance at germination stage of Guangxi rice landraces is higher than that at seedling stage. Salt tolerance of indica is stronger than japonica. Twelve salt tolerant rice germplasm resources including Yangcun 1 are selected out of seedlings with grade 1 salt tolerance at germination stage and grade 1 and 3 at seedling stage. These germplasm resources can be applied in salt tolerant parents breeding and salt tolerant genes exploration.