Comparison of Salinity Tolerance Between Grain and Sweet Sorghum Germplasms [Sorghum Bicolor (L.) Moench]

Abstract

In order to investigate salt-tolerant sorghum germplasms that can grow in saline soil from newly reclaimed land, we measured a well-established germination rate, and growth characteristics including leaf number, height, and root length in salt-treatment conditions (0.3, 0.6, 0.8, and 1.2%) and untreated control. The highly salt-tolerant sorghum line was confirmed using PCA (principal component analysis) analysis and fuzzy comprehensive evaluation method. Germination rate gradually decreased at doses higher than 0.3%, but the germination rates reached about 70% in IT124115, IS1041, Dansusu4ho, and Dansusu2ho germplasms. At 0.6% salt-treatment condition, the germination rates ranged from 35% to 100%. Only seven germplasms (IT103274, IT101381, IT104110, Dansusu4ho, IS20740, IS22720, and IS27887) had germination rates exceeding 50% at 0.8% salt-treatment. At 1.2% salt-treatment IT124115, IT028385, and IS1041 withered. The total number of leaves decreased similarly for both germplasms at salt levels below 0.6%, and sweet sorghum leaf count was more susceptible than grain sorghum at doses higher than 0.8%. In addition, the height of both germplasms was severely reduced even at low salt concentrations, whereas grain sorghum exhibited a greater sensitivity to salinity stress in terms of root length, while sweet sorghum had longer roots at low concentrations when compared with the untreated control. PCA analysis and fuzzy comprehensive evaluation showed that 29 sorghum accessions could be divided into 3 groups based on the germination rate and morphological traits. Especially, sweet sorghum accessions showed a different pattern of PCA plot when compared with the grain sorghum, and salt tolerance could be divided into 5 groups using MFV in terms of their traits. Taken together, the results from this work will contribute to the development of domestic agriculture utilizing marginal land such as reclaimed land by selecting elite sorghum germplasms that have a high salt tolerance and capacity.