不同基因型苦荞苗期抗旱性综合评价及指标筛选

发布时间：2018-03-31 10:07

本文选题：苦荞　切入点：抗旱指标筛选　出处：《中国农业科学》2017年17期

【摘要】：【目的】苦荞不仅具有丰富的营养价值和药用价值且具有耐冷凉、耐瘠薄、适应性强等生理特性,不同苦荞品种间的抗旱性差异显著,探讨苦荞苗期耐旱特性,筛选耐旱基因型材料及耐旱性鉴定指标并建立耐旱性数学评价模型,不仅能够为品种耐旱性评价与品种筛选奠定基础,更为黄土高原冷凉地区的种质选育提供理论依据。【方法】采用苗期沙培方式,设置正常供水CK和干旱胁迫DS两个处理,对9份不同苦荞品种在不同处理下的株高、茎粗、叶面积等农艺性状及根系活力、根系酶活性等生理指标进行测定。利用隶属函数法、主成分分析与聚类分析对各苦荞品种耐旱能力进行综合评价,并用逐步回归分析建立最优回归方程进而实现对苦荞耐旱能力的预测与鉴定。【结果】干旱胁迫对苦荞各指标均有显著影响,差异性分析结果表明,苦荞苗期地上部指标、根系干重、根系活力、根系形态指标、可溶性蛋白含量、相对含水量、叶绿素含量、Fm和Fv/Fm等指标与对照相比均明显下降;而根系酶活性、MDA含量、可溶性糖、游离脯氨酸含量、Fo与对照相比,表现为升高,且耐旱型品种的根冠比也表现为升高,中间型和不耐旱品种则表现为下降。主成分分析将21个单项指标转化为3个相互独立的综合指标(累计贡献率达87.30%),且第1主成分主要反映的是生物量、根系形态、叶片荧光参数等信息;第2主成分反映的是植株根系活力、根系酶活性和根系渗透调节物质等信息;第3主成分反映的是植株地上部形态及部分叶片和根系生理特性的相关信息。聚类分析将9个苦荞基因型划分为3类,分别为耐旱型、中间型和不耐旱型。为了对各基因型的耐旱能力进行预测并建立数学评价模型,将D值作因变量,各指标耐旱系数作自变量进行逐步回归分析。结果分析表明,通过建立最优回归方程,筛选出株高、茎粗、根冠比、根系活力、最大根长、MDA、Fo及水势等8项对苦荞耐旱能力有影响的指标,并且9个苦荞基因型的苗期耐旱能力预测值与D值极显著相关(R2=0.988**),表明用此方程对苦荞抗旱特性进行预测具有一定的准确性及高效性,进而在苦荞抗旱特性的鉴定工作中如果有选择的测定上述指标,可使鉴定工作简单化。【结论】干旱胁迫对苦荞苗期各指标均有显著影响。通过聚类分析图得出参试品种分为3大类型,即迪庆苦荞、西农9909和奇台农家品种为耐旱型品种;广苦1号、黔苦6号、云荞1号为中间型品种;多元苦荞、黑丰1号和西荞1号为不耐旱品种。确定了苗期耐旱能力预测值与D值极显著相关(R2=0.988**),筛选出株高、茎粗、根冠比、根系活力、最大根长、MDA、Fo及水势等指标,可作为苦荞抗旱特性快速鉴定的指标。
[Abstract]:[objective] Tartary buckwheat not only has rich nutritional value and medicinal value, but also has physiological characteristics such as cold tolerance, barren tolerance and strong adaptability. The drought resistance of different Tartary buckwheat varieties is significant, and the drought tolerance characteristics of Tartary buckwheat at seedling stage are discussed. The selection of drought tolerance genotypes and the evaluation index of drought tolerance and the establishment of mathematical evaluation model of drought tolerance can not only lay a foundation for drought tolerance evaluation and selection of varieties. The germplasm breeding in the cold area of the Loess Plateau provides theoretical basis. [methods] the plant height and stem diameter of 9 different Tartary buckwheat varieties under different treatments were treated with normal water supply CK and drought stress DS by means of sand culture in seedling stage. The agronomic characters such as leaf area, root system activity and root enzyme activity were determined. The drought tolerance of buckwheat varieties was evaluated by membership function method, principal component analysis and cluster analysis. The optimum regression equation was established by stepwise regression analysis to predict and identify the drought tolerance of Tartary buckwheat. [results] drought stress had a significant effect on each index of Tartary buckwheat. Root dry weight, root activity, root morphology index, soluble protein content, relative water content, chlorophyll content, Fm and Fv/Fm were all significantly decreased compared with the control, while the root enzyme activity and soluble sugar were significantly decreased compared with the control. Compared with the control, the content of free proline and the ratio of root to shoot of drought-tolerant varieties were increased. Principal component analysis (PCA) transformed 21 single indexes into 3 independent comprehensive indexes (cumulative contribution rate was 87.30%) and the first principal component mainly reflected biomass and root morphology. The second principal component reflected the plant root activity, root enzyme activity and root osmotic regulator. The third principal component reflects the relative information of plant shoot morphology and physiological characteristics of some leaves and roots. The nine Tartary buckwheat genotypes were classified into 3 groups by cluster analysis. In order to predict the drought tolerance ability of each genotype and establish a mathematical evaluation model, D value was taken as dependent variable and drought tolerance coefficient of each index was used as independent variable for stepwise regression analysis. By establishing the optimal regression equation, 8 indexes, such as plant height, stem diameter, root / shoot ratio, root activity, maximum root length MDAA Fo and water potential, were selected to influence the drought tolerance of Tartary buckwheat. The drought tolerance of nine Tartary buckwheat genotypes was significantly correlated with D value, which indicated that this equation had certain accuracy and high efficiency in predicting drought resistance of Tartary buckwheat. And then in the appraisal of the drought resistance characteristics of Tartary buckwheat, if there is a selective determination of the above indexes, [conclusion] drought stress has a significant effect on each index of Tartary buckwheat seedling stage. By cluster analysis, the tested varieties can be divided into three types, I. e., Diqing Tartary buckwheat, Xinong 9909 and Qitai Nongjia varieties are drought-tolerant varieties. Guangku-1, Qianku6, Yunxiao 1 were intermediate varieties, and multivariate Tartary buckwheat, Heifeng 1 and West buckwheat 1 were non-drought-tolerant varieties. The prediction value of drought tolerance at seedling stage was significantly correlated with D value. The plant height, stem diameter and root / shoot ratio were screened out. The indexes of root activity, maximum root length, MDA-Fo and water potential can be used as indexes for rapid identification of drought resistance characteristics of Tartary buckwheat.
【作者单位】：山西师范大学生命科学学院;山西师范大学地理科学学院;
【基金】：国家自然科学基金(31571604)
【分类号】：S517

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