| Saline-alkali stress seriously affects the normal growth and development of crops,and it is one of the main abiotic factors leading to crop yield reduction.Sweet sorghum belongs to an important food and feed dual-use materials in China.It is big practical significance to study the salt and alkali tolerance of sweet sorghum for agricultural development.In this research,we studied the different characteristics of different sweet sorghum varieties(lines)under saline-alkali environment,and screened and evaluated salt-tolerant materials,it provides germplasm resources and theoretical basis for the stress-resistant and efficient cultivation of sweet sorghum on saline-alkali soil.The experiment was carried out in Gaozhuang Township,Pingluo,Ningxia from 2018 to 2019.The field identification method was used to screen and identify the saline-alkali tolerance of 25 sweet sorghum materials;at the same time,we had screened highly saline-alkaline tolerant germplasm F6043,moderate saline-alkaline tolerant germplasm F6319 and F6158,saline-alkaline tolerant germplasm Dalishi and F6056,saline-alkaline sensitive germplasm F6271,these materials were seleced for further research.And we analysised the growth indicators,antioxidant systems,photosynthetic characteristics,fluorescence parameters and osmotic adjustment substances at different growth stages under different salt-alkali stresses.The main results are as follows:1.The performance of different sweet sorghum varieties(strains)in saline-alkali tolerance.Principal component analysis and membership function were used to order the salt-alkali tolerance,and cluster analysis was used to classify 25 different varieties(lines)of sweet sorghum into 4 categories.The category Ⅰ including 4 accessions of moderately saline-alkali tolerant germplasm;The Category Ⅱ including 10 accessions of saline-alkali tolerant germplasm;The category Ⅲincluding 8 accessions of sensitive germplasm,and the category Ⅳ including 3 accessions of highly sensitive germplasm.2.The morphological performance of different sweet sorghum varieties(strains)in saline-alkali tolerance.With the increase of the degree of saline-alkali stress,the plant height and stem thickness showed a decreasing trend.F6271 had the highest plant height and was significantly higher than other varieties(lines)(P<0.05).The stem thickness of F6043 and Dalishi were larger than other varieties(lines).Salt-alkali stress has different effects on plant height and stem thickness of different sweet sorghum varieties(lines)at different growth stages.Salt-alkali stress has the greatest impact on jointing stage during the whole growth periods.3.The physiological characteristics of different sweet sorghum varieties(strains)in saline-alkali tolerance.With the increase of salt-alkali stress,the activities of superoxide dismutase(SOD)and peroxidase(POD)of various sweet sorghum varieties(lines)showed increased and then decreased,the content of chlorophyll a and b decreased,and SOD activity,POD activity,chlorophyll a and b content of F6271 and F6043 are greater than other varieties(lines);Proline content(Pro)and soluble sugar content first increased and then decreased,Pro and soluble sugar content of F6319 and F6158 was better than other varieties(lines);Membrane permeability and MDA content increase,membrane permeability performance of F6043 is better than other varieties(lines),F6319 performance was better than other varieties(lines);Pro and soluble sugar content first increased and then decreased,F6043 and F6319 had better Pro and soluble sugar content than other varieties(lines);net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),Fv/Fm and Fv/F0 gradually decreased,Pn,Fv/Fm performance of F6043 is better than other varieties(lines),Gs and Fv/F0 performance of F6158 is better than other varieties(lines);Tr performance of F6319 is better than other varieties(lines),the root and stem K+/Na+performance of F6319 is better than other varieties(lines).The leaf K+/Na+ ratio of F6271 is better than other varieties(lines).4.The yield trait of different sweet sorghum varieties(strains)in saline-alkali tolerance.As the degree of salt-alkali stress increases,the yield,ear length,ear weight,ear grain weight,and thousand-grain weight between different sweet sorghum varieties(lines)all decreased.The greater the degree of salt-alkali stress,the greater the decrease and the more obvious the decrease in yield.The yield inhibition of Dalishi and F6158 was more significantly;the yield,ear length and ear weight of F6043 were all higher than those of other varieties(lines)under moderate saline-alkali stress.5.The performance of different sweet sorghum varieties(strains)at different growth stages in saline-alkali tolerance.The agronomic and physiological indicators of different sweet sorghum varieties(lines)were studied under moderate saline-alkaline stress conditions.Through comprehensive evaluation,correlation and principal component analysis,the order of saline-alkali tolerance at jointing stage is F6158>F6043>Dalishi>F6319>F6271>F6056;the order of saline-alkail tolerance at booting stage is Dalishi>F6319>F6056>F6158>F6043>F6271;the order of saline-alkail tolerance at the filling stage is F6158>F6043>F6271>Dalishi>F6319>F6056;the order of saline-alkail tolerance during maturity is F6056>F6271>F6158>F6319>F6043>Dalishi;the order of saline-alkail tolerance during harvest is F6043>F6319>F6158>Dalishi>F6056>F6271.6.T Screening of index system for identification of saline-alkali tolerance of sweet sorghum.Interaction analysis showed that different sweet sorghum varieties(lines)genotype(G)×treatment(T),growth periods(S)× G and S × T × G interaction on plant height,stem thickness,Pn,Gs,Fv/Fm,chlorophyll a,SOD,POD and Pro have extremely significant effects(P<0.01),and these can be used as the indices to identify the mechanism of salt-alkali tolerance of sweet sorghum.The interaction of S × G,G × T and S × T × G had no significant effect on F0,Fm,stem K+/Na+ratio and MDA,and they could be used as screening indices for saline-alkali tolerant varieties(lines)of sweet sorghum under different saline-alkali stress.7.Different sweet sorghum varieties(lines)are suitable for planting on different saline-alkali lands.The F6043 and F6158 show good saline-alkali tolerance,and they are suitable for cultivated in saline-alkali land with a total salt content of 5.45 g/kg and the pH 9.23;Dalishi and F6319 are suitable for cultivated in saline-alkali land with a total salt content of 2.89 g/kg and the pH 9.05;and F6271 is suitable for cultivated in saline-alkali land with a total salt content of 1.41 g/kg and pH 8.91. |
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