核桃群体核仁脂肪酸组成分析

Analysis of Kernel Fatty Acid Contents in Walnut(Juglans regia L.)Population

为探明核桃群体脂肪酸组分的表型变异及相关关系,本研究采用索氏提取和气相色谱法对53份核桃种质的核仁样本进行脂肪酸组分及含量测定,运用回归分析、聚类分析、主成分分析明确脂肪酸组分的表型变异、相关性以及群体结构。结果表明,从53份核桃种质中共检测到亚油酸、油酸、亚麻酸、棕榈酸、硬脂酸、棕榈油酸及花生烯酸7种脂肪酸组成因子,总含量可达核仁油脂总量的99%以上。主成分分析表明,亚油酸、油酸、亚麻酸和棕榈酸为核仁油脂主要构成因子,棕榈油酸和花生烯酸含量较少。基于主要构成因子进行聚类分析,53份核桃种质可以分为两个亚群——group_1和group_2,其中group_1包含28个材料,group_2包含25个材料;亚油酸、油酸和亚麻酸含量在两个亚群间存在显著差异(P<0.01),棕榈酸在两个亚群间无显著差异;群体水平上同一种植区核桃品种核仁亚油酸和棕榈酸含量变异相对较稳定;油酸及亚麻酸变异幅度较大,且相关分析表明油酸与亚油酸、亚麻酸显著负相关(P<0.01)。因此,可以根据不同需求侧重不同的目标性状选育核桃新品种。本研究结果可为选育脂肪含量高、脂肪酸组成及比例合理的核桃新品种提供一定的理论参考。

In order to explore the phenotypic variation and correlations of fatty acid components in walnut(Juglans regia L.)population,the fatty acid composition and contents of 53 walnut samples were determined by soxhlet extraction and gas chromatography in this study.The correlation,regression,cluster and principal component analyses were adopted to analyze the phenotypic variation,the relationships and population structure of the 53 walnut accessions.Seven components were detected including linoleic acid,oleic acid,linolenic acid,palmitic acid,stearic acid,palmitioleic acid and arachidonic acid,and their total content reached more than 99%of the total nucleolar fat.Principal component analysis showed that linoleic acid,oleic acid,linolenic acid and palmitic acid were the main components of kernel fat,while palmitic oleic acid and arachidonic acid were less.Cluster analysis based on the main components showed that the 53 walnut germplasms could be divided into two subgroups,group_1 and group_2;and group_1 contained 28 materials and group_2 contained 25 materials.There were significant differences in linoleic acid,oleic acid and linolenic acid contents between the two subgroups,but no significant difference in palmitic acid content.At the population level,the variation of linoleic acid and palmitic acid contents in kernel of walnut varieties in the same planting area was relatively stable.Oleic acid and linolenic acid varied greatly.And correlation analysis showed that oleic acid was negatively correlated with linoleic acid and linolenic acid.Therefore,new varieties of walnut could be selected and bred according to different needs and focusing on different target traits.This study could provide some theoretical references for breeding new varieties of walnut with high fat content and reasonable fatty acid composition and proportion.