苦玄参40个株系表型性状遗传多样性分析

Analysis of phenotypic character genetic diversity of 40 lines of Picria felterrae

关键词:  苦玄参, 表型性状, 变异, 遗传多样性, 聚类分析

Key words:  Picria felterrae, phenotypic character, variation, genetic diversity, cluster analysis

摘要:

植物遗传多样性一直以来是种质资源研究的热点。为揭示苦玄参栽培种质的遗传多样性,该研究从苦玄参常年栽培种中根据形态学性状差异选择40个株系,以产量、药效物质含量及茎、叶、花等形态学性状为指标,进行物种变异和遗传多样性分析,并对其进行聚类分析,获取各株系遗传亲缘关系。结果表明:苦玄参苷I_A和I_B含量的遗传变异系数较高,分别为24.225%和17.853%; 遗传多样性指数高,分别为1.920和2.075。产量遗传变异系数较低,仅为3.637%,但遗传多样性指数较高,达到1.884。其余表型性状指标遗传变异系数均较高,其中花色高达127.794%。数值型性状具有较高的遗传多样性,均大于1,但描述型指标遗传多样性指标较低,均小于1。聚类分析可将供试材料分为4个大的类群:第Ⅰ类群共有7个株系,此类群产量性状及相关指标平均数较高; 第Ⅱ类群有8个株系,茎节长度最长,其余指标中等偏下; 第Ⅲ类群数量最多,有20个株系,各指标均较低; 第Ⅳ类群有5个株系,苦玄参苷含量和产量均较高,综合指标比较优。相关分析结果表明,苦玄参苷I_A的含量与叶缘性状具有显著相关,产量性状与茎节长度、一级分枝和末级分枝数具有极显著相关,选择优良种质应注重该4个性状的选择。该研究结果表明目前苦玄参栽培种具有广泛的变异和较高的遗传多样性,为苦玄参资源的利用提供了参考依据。

Abstract:

Plant genetic diversity has been one of the hot spots in the research into germplasm resources. To disclose the genetic diversity of cultivated germplasm of Picria felterrae, we selected 40 lines from perennially cultivated individuals based on morphological differences and analyzed species variation and genetic diversity with yield, active ingredient content as well as morphological characters including the stem, leaf and flower as the indicator; and wemade cluster analysis to obtain the genetic relationships between lines. The results showed that there was much genetic variance in the content of picfeltarraenins I_A and I_B, the coefficients being 24.225% and 17.853%, respectively; and the genetic diversity indexes were high, 1.920 and 2.075, respectively. For the yield, the coefficient of genetic variance was comparatively low, only 3.637%, and the genetic diversity index was 1.884. There was also much genetic variance in other phenotypic characters, among which the coefficient of genetic variance of flower color was 127.794%. All genetic diversity indexes for numerical characters were higher than one while those for descriptive characters were lower than one. The test materials were divided into four groups in the cluster analysis: Group Ⅰ consisted of seven lines which had a high yield and related indexes on average; Group Ⅱ included eight lines which had the longest stem nodes and whose other indexes were at or below the moderate level; Group Ⅲ comprised 20 lines with low indexes in all respects; and Group IV included five lines, all of which were high in yield and content of picfeltarraenins and had a better integrated index. The correlation analysis showed that the content of picfeltarraenin I_A was significantly related to leaf margin characters, and the yield was significantly correlated to stem node length and primary and final branching numbers, so the above four characters should be given priority when selecting the best germplasm. The results indicate that extensive variation and high genetic diversity are present in current cultivated individuals of Picria felterrae, which can be used as a reference for the utilization of resources of that species.