| Sweet sorghum（Sorghum bicolor L.） is characterized by drought and floodresistance, salt tolerance and high efficiency of biomass accumulation. It is consideredto be one of the most promising bio-energy crops. Choosing drought-resistant andsalt-enduring varieties is the most economic, safe and effective method in improvingthe products and qualities of sweet sorghum. The experimental material comprising oftwenty-nine sweet sorghum genotypes（cultivars and experimental lines） and two grainsorghum. Screening of sweet sorghum germplasm tolerant to drought and saline-alkalistress under different three inhabits in west Jilin of China. This study elucidated thechanges of physiological and biochemical indices under drought and saline-alkalistress in sweet sorghum systematically and revealed that the drought-resistant andsalt-enduring mechanisms of the sorghum, so it could provide the theoretical basis inselecting the drought-resistant and salt-enduring varieties and planting on drought andsaline-alkali soil. Thirty-one diverse genotypes of sweet sorghum were evaluated anddetermined their callus induction and plant regeneration capabilities using immatureinflorescences as explants. This study has identified the sweet sorghum genotypeswith the best potential for callus production and whole-plant regeneration in culture.This information is essential for successful genetic transformation of sweet sorghum.The results are as follows:1. Screening of sweet sorghum germplasm tolerant to drought and saline-alkali stress.The sweet sorghum emergence averaged75.1%under saline-alkali stress. Thesignificant difference in emergence of different sweet sorghum genotypes existed.JiuTian4sweet sorghum showed the greatest emergence, while MN-3020andMN-2745had the lowest.Variance analysis and multiple comparisons showed significant difference in fresh biomass yields, dry biomass yields, Brix degree of juice, theoretical ethanol yields ofthe31sweet sorghum genotypes grown in three inhabits.The variability of fresh biomass yields was from23.3t·hm-2to101.9t·hm-2in E1inhabit, from10.4t·hm-2to54.8t·hm-2in E2inhabit and from20.8t·hm-2to101.2t·hm-2in E3inhabit. The coefficient of variation was17.43%,49.90%,13.93%,respectively. The variability of dry biomass yields was from5.7t·hm-2to23.8t·hm-2in E1inhabit, from3.0t·hm-2to13.4t·hm-2in E2inhabit and from3.5t·hm-2to23.8t·hm-2in E3inhabit. The coefficient of variation was9.12%,11.71%,11.16%,respectively. The variability of Brix degree of juice was from12.9%to22.8%in E1inhabit, from6.4%to19.1%in E2inhabit and from8.2%to18.4%in E3inhabit. Thecoefficient of variation was11.84%,17.50%,9.18%, respectively. The variability oftheoretical ethanol yields was from1771L·hm-2to9608L·hm-2in E1inhabit, from577L·hm-2to5454L·hm-2in E2inhabit, from911L·hm-2to9154L·hm-2in E3inhabit. The coefficient of variation was11.09%,13.36%,9.02%, respectively. Theresults showed fresh biomass yields, dry biomass yields, Brix degree of juice,theoretical ethanol yields of each sweet sorghum genotypes were different in the sameinhabit.Fresh biomass yields showed the highest yields under E3(averaged55.8t·hm-2)and showed the lowest yields under E2(averaged28.1t·hm-2). Dry biomass yieldsshowed the highest yields under E3(averaged13.6t·hm-2) and was similar underE1(averaged13.2t·hm-2).The lowest yields (averaged7.2t·hm-2) showed under E2.Brix degree of juice showed the highest under E1（averaged18.2%）. E3was similar toE1（averaged15.7%,15.2%, respectively）. Theoretical ethanol yields showed thehighest yields under E3(averaged4864L·hm-2) and was similar to E1(averaged4854L·hm-2). E2showed the lowest yields (averaged2426L·hm-2). Fresh biomass yields,dry biomass yields, Brix degree of juice, theoretical ethanol yields of the31sweetsorghum genotypes were different in three inhabits.The energy traits of31sweet sorghum genotypes were analyzed with AMMImodel and biplot using data from three inhabits, and then the stability and adaptabilityof different genotypes were evaluated. According to the high-yield, high-sugar, high stability screening criteria, genotypes of JiuTianⅢand SanSuiTian were suitable forplanting in saline-alkali soil. Theoretical ethanol yields were5454L·hm-2and4605L·hm-2, respectively under saline-alkali stress. The theoretical ethanol yields ofJiuTian3was7761L·hm-2under drought stress.2. Physiological and Biochemical characteristic responses of drought andsaline-alkali stress resistance in different sweet sorghum genotypes.Four different genotypes, JiuTianⅢ, SanSuiTian, MN-3018and MN-3382, ofsweet sorghum were used as materials to assayed the comparison of physiologicalcharacteristic in various growth stages. The rate of relative electrolyte, content ofMDA, proline and activity of SOD, POD, CAT showed the lowest under E3andshowed the highest under E2. And physiological characteristic showed significantdifferences among the four sweet sorghum genotypes, the change of JiuTianⅢandSanSuiTian were higher than MN-3018and MN-3382. The change of physiologicalcharacteristic showed that plasma membrane serious damaged under drought,saline-alkali stress. The rate of relative electrolyte, content of MDA, proline andactivity of SOD, POD, CAT in leaves were all increased in order to adapt to stress.The change of physiological characteristic may be the indexes of screening sweetsorghum genotypes for drought, saline-alkali tolerance.Saline-alkali stress affects the total soluble sugar, sucrose, fructose and glucose instalks of sweet sorghum. There were significant differences in different genotypes.3. Evaluation of regeneration potential of sweet sorghum genotypes.Twenty-nine of31genotypes of sweet sorghum were able to form calli and16genotypes were able to regenerate whole plants. Variance analysis showed significantdifferences in callus induction and plant regeneration frequency among differentgenotypes. Variance analysis showed significant difference in callus inductionfrequency among different media, indicating that2,4-D and KT concentrationsaffected callus induction frequency. The highest callus induction rate was obtained onY3medium [MS medium+3mg l-12,4-D+0.5mg l-1KT] with an average inductionrate of40.1%. The amount of phenolic compounds produced varied widely among thedifferent genotypes. The sweet sorghum genotypes MN-3020,1788,JiuTianⅠ,JiTian Ⅲ, and685-525showed the best callus induction and regeneration capabilities inthese conditions. |
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