| 摘要: |
| 【目的】对苜蓿52份种质资源进行抗旱性鉴定和抗旱指标筛选，为抗旱苜蓿新品种的选育提供基础材料和理论依据。【方法】采用盆栽反复干旱胁迫法对52份苜蓿种质材料进行了干旱胁迫，测定其株高、叶长、叶宽、叶面积、叶片相对含水量、相对叶绿素含量、净光合效率、气孔导度、蒸腾速率、水分利用率、PSⅡ最大光化学量子产量等11个相关指标，计算各个指标的抗旱系数和52份材料的抗旱性综合度量值、综合抗旱系数、加权抗旱系数，以抗旱系数为基础，结合相关分析、主成分分析、灰色关联度分析、逐步回归和聚类分析等统计分析，综合评价不同苜蓿材料抗旱性，并筛选抗旱性指标。【结果】干旱胁迫对苜蓿的11个指标均有极显著影响，但敏感程度不同；主成分分析、灰色关联度分析和逐步回归分析表明，净光合速率、叶宽、PSⅡ最大光化学量子产量、叶长、叶面积与苜蓿抗旱性关系密切。根据系统聚类结果，依据每类材料抗旱性综合度量值的均值大小将材料的抗旱性划分为极强、强、中等、弱和极弱5个等级。【结论】净光合速率、叶宽、PSⅡ最大光化学量子产量、叶长和叶面积可作为苜蓿种质苗期抗旱性鉴定指标；筛选出苜蓿苗期抗旱能力极强的品种有标杆(ZHMX)、甘农3号、威廉斯、草原3号、3010、MT3015、SPYDER和0129苏联，抗旱能力极弱的品种有甘农1号、甘农2号、礼县、WL656和爱开夏。 |
| 关键词: 苜蓿种质 苗期 光合特性 抗旱性 综合评价 |
| DOI： |
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| 基金项目:宁夏自然科学基金项目（NZ17019）；宁夏牧草育种专项（2014NYYZ04）；宁夏大学草学一流学科建设项目（NXYL-XK2017A01）；宁夏青年科技人才托举工程项目（TJGC2018083） |
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| Screening of drought resistance indices and comprehensive evaluation of alfalfa germplasm resources based on leaf morphology and photosynthetic characteristics at seedling stage |
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CHANG Wei,LI Xue,ZHOU Yanfei,et al
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| Abstract: |
| 【Objective】Drought resistance identification and drought resistance index selection of 52 alfalfa germplasm resources were conducted to provide basis for the selection and breeding of new drought resistant varieties.【Method】Drought stress was applied to 52 alfalfa germplasm materials in pots using repeated drought method.Eleven indicators including plant height,leaf length,leaf width,leaf area,leaf relative water content,relative chlorophyll content,net photosynthetic rate,stomatal conductance,transpiration rate,water use efficiency and PSⅡmaximum quantum yield of photochemical reaction were measured.The drought resistance coefficient of each index and the comprehensive measure value,comprehensive drought resistance coefficient and weighted drought resistance coefficient of 52 materials were calculated.The statistical analysis based on drought resistance coefficients including correlation analysis,principal component analysis,grey correlation analysis, stepwise regression and cluster analysis were conducted,the drought resistance of each alfalfa material was evaluated comprehensively and the drought resistance indexes were selected.【Result】Drought stress had significant effects on 11 indicators of alfalfa with different sensitivities.Principal component analysis,grey correlation analysis and stepwise regression analysis showed that net photosynthetic rate,leaf width,maximal quantum yield of PSⅡ,leaf length and leaf area were closely related to drought resistance.According to system clustering based on average value of comprehensive measure value,the drought resistance was divided into five grades of very strong,strong,medium,weak and very weak.【Conclusion】Net photosynthetic rate,leaf width,maximal quantum yield of PSⅡ,leaf length and leaf area can be used as indicators for drought resistance evaluation of alfalfa germplasm at seedling stage.Varieties with very strong drought resistance at seedling stage included Biaogan (ZHMX),Gannong No.3,Williams,Caoyuan No.3,3010,MT3015,SPYDER and 0129 Soviet Union,while varieties with very weak drought resistance included Gannong No.1,Gannong No.2,Lixian,WL656 and Ackershlre. |
| Key words: alfalfa germplasm seedling stage photosynthetic characteristics drought resistance comprehensive evaluation |
