小麦源库优异种质的鉴定与源库类型的划分

Identification of Excellent Wheat Germplasms and Classification of Source-Sink Types

【目的】筛选源库评价指标,划分试验材料的源库类型,探究源库关系对小麦农艺、产量及品质性状的影响,为小麦源库代谢研究和遗传育种应用提供参考。【方法】以国内外190份小麦种质资源为试验材料,测定其源代谢、库代谢相关性状,利用主成分分析对小麦的源库代谢能力进行评价,根据综合得分对优异小麦材料进行筛选。以源活性综合得分、源大小(叶面积)、库活性综合得分、库数目(穗粒数)为指标进行层次聚类,根据聚类结果总结小麦材料的源库类型,分析不同区域小麦源库特征差异,比较不同源库类群间小麦的农艺性状、产量性状、品质性状的差异。【结果】通过主成分分析将6个与小麦源活性密切相关的指标转化为3个独立指标(光化学淬灭系数、最大光合潜力和叶绿素含量),将5个与库活性密切相关的指标转化为2个独立指标(最大灌浆速率和灌浆持续期),累计贡献率分别为82.80%和92.90%,筛选出源活性、源大小(叶面积)、库活性、库数目(穗粒数)排名前十的小麦品种。根据源库关系,将供试的190份小麦材料划分为三大类八小类:源足库乏型(源中库弱型、源强库中型)、源乏库足型(源中库强型、源弱库中型)和源库平衡型(受限于库活性的源弱库弱型、受限于源活性和穗粒数的源弱库弱型、源中库中型、源强库强型),其中,受限于源活性与穗粒数的源弱库弱型、源中库强型、源强库强型包含了大多数品种,占所有材料的76.84%。国内多数小麦品种源库关系相近,源活性、叶面积、穗粒数处在中等水平,库活性较高,长江中下游冬麦区品种库活性较低。不同类群间,株高、穗下节长、小穗数表现为源足库乏型>源库平衡型>源乏库足型,籽粒蛋白质干基、湿面筋干基、沉降值总体表现为源足库乏型>源库平衡型>源乏库足型,籽粒吸水率表现为库活性越强吸水率越高,单株产量在不同源库类群间表现不一,但在品种较多的三类中单株产量与源活性和穗粒数皆呈正相关。【结论】光化学淬灭系数、最大光合潜力、叶绿素含量可作为评价小麦源活性的主要指标,最大灌浆速率、灌浆持续期可作为评价小麦库活性的主要指标。在实际生产中可通过提高穗粒数和源活性的方式提高小麦产量,源的供应能力相对强于库的吸收能力将促进小麦株高、穗下节长、小穗数、蛋白质干基、湿面筋干基、沉降值的增加,较强的库活性有助于提高小麦籽粒的吸水率。

【Objective】The aim of this study is to screen the evaluation indexes of wheat source-sink and classify the source-sink types.In addition,the relationships between different source-sink types and the agronomic traits,yield and grain quality of wheat were also clarified,which provides a better understanding of wheat source-sink metabolism and wheat breeding.【Method】In this study,the related agronomic traits of source metabolism and sink metabolism of 190 wheat varieties which from different regions were measured.Then,the source-sink metabolic capacity of wheat was evaluated by principal component analysis,and the superior wheat materials were selected according to the composite score.Furthermore,the hierarchical clustering was conducted based on the source size(leaf area),source activity,sink number and sink activity.Then,based on the clustering results,the source-sink types of wheat were classified and the source-sink characteristics of different region of wheats were analyzed.Meanwhile,the agronomic,yield and quality traits of different wheat source-sink types were compared and analyzed.【Result】For better understanding the results,six indicators related to source activity were converted into three independent indicators(photochemical quenching coefficient,maximum photosynthetic potential,chlorophyll content),and five indicators related to sink activity were converted into two independent indicators(maximum filling rate,filling duration)based on the principal component analysis.The cumulative contributions of three source activity indicators and two sink activity indicators were 82.80%and 92.90%,respectively.Then the top 10 wheat varieties were screened based on the source activity,source size(leaf area),sink activity,and sink number(number of spike grains).According to the source-library relationship,all the wheat varieties were divided into three major categories and eight subcategories,including sufficient source-weak sink type(medium source-weak sink type,strong source-medium sink type),weak source-sufficient sink type(medium source-strong sink type,weak source-medium sink type)and source-sink balance type(weak source-weak sink type limited by sink activity,weak source-weak sink type limited by source activity and grain number per spike,medium source-medium sink type,and strong source-strong sink type).76.84%of wheat lines were contained in three subcategories(weak source-weak sink type,the medium source-strong sink type,and strong source-strong sink type),other wheat lines were distributed in other subcategories evenly.Most wheat varieties of China showed similar source-sink relationship,which presented the medium level of source activity,leaf area and grain number per spike,while the sink activity was high.But the sink activity of wheat varieties which were cultivated at the middle and lower reaches of the Yangtze River is low.The plant height,length of uppermost internode and spikelet number in different categories indicated that the sufficient source-weak sink type>source-sink balance type>weak source-sufficient sink type,and the dry protein content,dry wet gluten content and sedimentation value in different categories showed that source-weak sink type>source-sink balance type>weak source-sufficient sink type.Grain water absorption showed that the stronger the sink activity had the higher the water absorption rate.The yield of per plant was different among different source-bank groups,but it was positively correlated with the source activity and the number of grains per spike in the three subcategories which contained most wheat varieties.【Conclusion】In this study,photochemical quenching coefficient,maximum photosynthetic potential and chlorophyll content could be used as the main indexes to evaluate the activity of wheat source.The maximum filling rate and filling duration could be used as the main indexes to evaluate the activity of wheat sink.In practical production,the wheat yield could be improved by increasing the number of grains per spike and the activity of source.When the supply capacity of source is stronger than the absorption capacity of sink,the plant height,peduncle length,spikelet number,dry protein content,dry wet gluten content and sedimentation value would be increased.Strong sink activity would help us to improve the water absorption of wheat grains.