Germination Characteristics of Flue-cured Tobacco Varieties under Mixed Salt-alkali Stresses and Evaluations of Their Saline-alkali Tolerance

The aim of the study was to evaluate the saline-alkali tolerance of different flue-cured tobacco varieties and screen for flue-cured tobacco varieties suitable for growing in saline-alkali soils.Five flue-cured tobacco varieties (Yunyan87,K326,Honghuadajinyuan,Yunyan97 and Zhongyan100) were treated with 0,0.2%,0.4%,0.6%,0.8% and 1% saline alkali with n(NaCl):n(Na2SO4):n(NaHCO₃)=1:1:1.Germination rate,germination potential,germination index,vigor index,salt injury index,fresh and dry weight per plant were recorded.The results showed that the low concentration (0.2%,0.4%) saline-alkali treatments promoted the germination rate and viability of K326,Honghuadajinyuan and Yunyan97 in different degrees,and the germination indexes of Honghuadajinyuan and K326 were higher than CK.High concentrations (≥ 0.6%) of saline-alkali inhibited the germination rate,viability and index of all varieties.Dry weight decreased with the increase of saline-alkali concentration,and salt injury rate increased with salt concentration.The low concentration saline-alkali solutions could promote some varieties of flue-cured tobacco (Honghuadajinyuan,Yunyan97),while high concentration saline-alkali solutions had strong inhibition effects on germination of testing varieties.Under low salinity (0.2%,0.4%),Honghuadajinyuan,Yunyan87 and K326 had similar tolerance to salinity-alkalinity stresses with a good performance,while Yunyan97,Zhongyan100 had poor performance.Under high concentrations (≥ 0.6%) of saline-alkali,K326 and Yunyan97,Yunyan87 performed better,followed by Honghuadajinyuan,and Zhongyan100 had a bad performance.