对南京地区种植的76株薄壳山核桃〔Carya illinoinensis （Wangenh.） K. Koch〕实生单株的8项果实性状和种仁中5种脂肪酸含量的差异以及各指标的相关性进行分析，并筛选出单项性状优良的单株；在此基础上，结合主成分分析结果，对供试76株单株的果实品质进行综合评价。结果显示：8项果实性状（包括坚果质量、种仁鲜质量、坚果壳厚度、坚果纵径、坚果横径、果形指数、出仁率和含油率）以及种仁中5种脂肪酸（包括棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸）的含量均有较大变异，变异系数为6.63％～28.99％，其中，出仁率的变异系数最小，亚麻酸含量的变异系数最大，8项果实性状的变异系数总体上小于5种脂肪酸含量的变异系数。部分果实性状间极显著或显著正相关，少数果实性状间极显著或显著负相关，而5种脂肪酸含量间均极显著正相关，但脂肪酸含量与果实性状间总体上无显著相关性。主成分分析结果表明：在8项果实性状中，与坚果大小有关的性状较为重要；而5种脂肪酸含量均同等重要。对果实性状和脂肪酸含量的主成分分析结果显示：第1主成分的决定指标包括含油率以及棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸的含量，第2主成分的决定指标包括坚果质量、种仁鲜质量、坚果壳厚度和坚果横径，说明薄壳山核桃果实评价的首要指标为种仁中脂肪酸含量，其次为果实大小。在利用坚果质量、种仁鲜质量、坚果壳厚度、出仁率、含油率、果形指数、油酸含量和不饱和脂肪酸含量8个单项指标优选单株的基础上，结合主成分分析结果，71号单株的综合得分较高，其种仁鲜质量、含油率以及油酸和不饱和脂肪酸的含量均较高，可作为优良品种选育的首选候选单株。根据上述研究结果，建议在薄壳山核桃不同育种目标的优良品种选育工作中，将主成分分析法作为单项性状筛选法的有效补充方法。

Differences in eight nut traits and five fatty acid contents in kernel among 76 seedling individuals of Carya illinoinensis （Wangenh.） K. Koch planted in Nanjing and correlation among all indexes were analyzed， and individuals with superior single trait were screened. On this basis, combined with principal component analysis result， nut quality of 76 individuals tested was comprehensively evaluated. The results show that there are large variations in eight nut traits （including nut weight， fresh weight of kernel， nutshell thickness， nut length， nut width， nut shape index， kernel rate and oil content） and contents of five fatty acids （including palmitic acid， stearic acid， oleic acid， linoleic acid and linolenic acid） in kernel， with coefficient of variation （CV） of 6.63％-28.99％. In which， CV value of kernel rate is the smallest， and that of linolenic acid content is the largest. Generally， CV value of eight nut traits is smaller than that of five fatty acid contents. There are obviously significant or significant positive correlations among some nut traits， and obviously significant or significant negative correlations among a few nut traits. There are obviously significant positive correlations among five fatty acid contents， but correlations between fatty acid contents and nut traits are almost unsignificant. The results of principal component analysis show that traits related to nut size are more important than others among eight nut traits， while five fatty acid contents are equally important. The result of principal component analysis on nut traits and fatty acid contents shows that the decision indexes in the first principal component include oil content and contents of palmitic acid， stearic acid， oleic acid， linoleic acid and linolenic acid， and those in the second principal component include nut weight， fresh weight of kernel， nutshell thickness and nut width， indicating that fatty acid content in kernel is the first index to evaluate nut quality of C. illinoinensis， followed by nut size. Based on superior individuals with eight single indexes of nut weight， fresh weight of kernel， nutshell thickness， kernel rate， oil content， nut shape index， oleic acid content and unsaturated fatty acid content， and combined with principal component analysis result， comprehensive score of No. 71 individual is relatively high, its fresh weight of kernel， oil content and contents of oleic acid and unsaturated fatty acid are relatively high， and No. 71 individual could be used as the first candidate individual for cultivating excellent cultivar. Based on above results， it is suggested that principal component analysis method can be used as an effective supplement for single trait selection in cultivating superior cultivar of C. illinoinensis for different breeding objectives.