毛梾天然群体种实表型多样性研究

Study on phenotypic diversity of seeds and fruits' characteristics in Cornus walteri

【目的】通过对全国毛梾主要自然分布区种实性状的大量调查及测算,研究毛梾种实性状的自然变异特点和地理变化规律,为毛梾全国选优策略和栽培区划的制定提供科学依据。【方法】以毛梾主要分布区的9个具有代表性的群体为研究对象,对种子直径、种壳厚度、百果质量等9个种实性状进行了系统比较分析,采用巢式设计方差分析、多重比较、相关分析、聚类分析等数学方法,探讨毛梾种实在群体间及群体内的表型多样性。【结果】毛梾种实性状在群体间及群体内存在丰富的变异,群体间平均表型分化系数为23%。果皮厚度、种壳厚度、实壳比的变异系数分别为27.42%,25.03%和25.19%,而种子直径的变异系数仅为9.61%。9个表型性状之间多数呈极显著或显著相关。果皮厚度与纬度呈显著正相关(R=0.808),种壳厚度与纬度、降水量均有显著相关性(R=-0.892,0.787),实壳比则与经、纬度呈显著相关(R=0.815,0.850)。利用群体间欧氏距离进行UPGMA聚类分析表明,毛梾群体可以划分为3类。【结论】群体间种实性状变异小于群体内变异,果皮与种壳的变异较大,而种子直径的稳定性较强。杨凌和青州的变异程度较其他群体高且杨凌种子的综合品质最好,边缘群体与中心群体差异较为明显。在空间分布上,实壳比与经、纬度呈双向变异模式,果皮厚度、种壳厚度与纬度显著相关,种壳厚度与年降水量呈显著正相关。

【Objective】 In order to provide scientific basis for the national strategy and development of cultrural division of Cornus walteri,morphological characteristics of seeds and fruits were investigated and determined in major natural distribution,which also can reveal natural variation and geographic evolution.【Method】 The subjects of the study were 9 representative populations of C.walteri from main natural distributions in china.Phenotypic diversities among/within population were discussed by comparing and analyzing 9 morphological characteristics of seeds and fruits such as seed diameter,shell thickness,the weight per 100 fruits and so on.The methods of nest design,multi-comparison,related analysis and hierarchical cluster analysis were used for analysis of experimental results.【Result】 There were significant differences in phenotypic variation among populations and among individuals within populations.The mean phenotypic differentiation coefficient VST between populations was 23%.In different individuals within populations,the CV of three phenotypic traits（pericarp thickness,shell thickness,solid-shell ratio） was 27.42%,25.03% and 25.19%,respectively,while the CV of seed diameter was only 9.61%.Most phenotypic traits were highly significantly or significantly correlated.Pericarp thickness and the latitude had a significantly positive correlation（R=0.808）,shell thickness,latitude and rainfall were significantly correlated（R=-0.892,0.787）,fruit-shell ratio was significantly correlated with the latitude and longitude simultaneously（R=0.850,0.815）.The 10 populations of C.walteri investigated could be divided into three groups according to the UPGMA cluster analysis.【Conclusion】 Phenotypic variation of seeds and fruits between populations was greatly smaller than that within populations.The traits stability of seed diameter was higher than that of other traits,compared to other characters,there was a big variation in pericarp and shell.The degree of variation of Yangling and Qingzhou was higher than that of other populations,moreover,the integrated quality of seeds from Yangling was the best.The solid-shell ratio of natural populations within C.walteri species was affected mainly by latitude and longitude in spatial distribution.Pericarp thickness and shell thickness were significantly related to latitude,while shell thickness was positively related to precipitation.