Variation in leaf morphology and architecture, phytochemical content, and antioxidant capacity among 36 <i>Camellia sinensis</i> clones of the Indian sub-Himalayan region

<i>Camellia sinensis,</i> renowned as the second most widely consumed nonalcoholic beverage worldwide, bears substantial economic importance, prompting cultivators to breed various clones for enhanced flavor and quality. This study analyzed the variation in leaf phenotype, phytochemicals (total tannins and proanthocyanidins content) and antioxidant potential of 36 widely cultivated tea clones from India’s sub-Himalayan region using multivariate analysis. Results indicated that TV23 had the largest leaf and SS27 and RR had the smallest. TS520 was the richest in tannin, proanthocyanidins, and antioxidants, while S3A1 and Heeleakah were the least. Principal components analysis (PCA) and cluster analysis unveiled four morphological clusters (representative clones - TV1, TV23, TV30, 124.48.8) and four phytochemical clusters (representative clones - TS520, TV9, TV27, P126). GC-MS analysis revealed that TV1 and TV30 had high caffeine content (82.0%), while TS520 exhibited abundant antioxidant compounds, including sycllo-inositol (23.84%) and epigallocatechin (4.23%). TS520’s exceptional antioxidant properties, confirmed by DPPH, ABTS, and total antioxidant capacity assays, may result from its cultivation through seed propagation. Correlation analysis showed antioxidant potential had moderate negative associations with leaf size, strong negative with inter-secondary vein number, and positive with petiole length. This study is pivotal for assessing tea clone diversity, with broader applications in tea improvement and breeding programs.

茶树（Camellia sinensis）作为全球第二大消费型非酒精饮品而闻名于世，具备极高的经济价值，为此种植者培育了诸多无性系以优化风味与品质。本研究采用多变量分析方法，对来自印度喜马拉雅山南麓地区的36个主流栽培茶树无性系的叶片表型、植物化学成分（总单宁与原花青素含量）以及抗氧化潜力进行了变异分析。结果显示，TV23的叶片最大，SS27与RR的叶片最小。TS520的单宁、原花青素与抗氧化物质含量最高，而S3A1与Heeleakah的相关含量最低。主成分分析（PCA）与聚类分析结果显示，可将供试材料划分为4个形态学聚类群（代表无性系分别为TV1、TV23、TV30、124.48.8）以及4个植物化学聚类群（代表无性系分别为TS520、TV9、TV27、P126）。气相色谱-质谱联用（GC-MS）分析显示，TV1与TV30的咖啡因含量较高（82.0%），而TS520含有丰富的抗氧化成分，包括环己六醇（sycllo-inositol，23.84%）与表没食子儿茶素（epigallocatechin，4.23%）。经DPPH、ABTS与总抗氧化能力测定验证，TS520具备优异的抗氧化特性，这可能与其实生繁殖的栽培方式有关。相关性分析结果表明，抗氧化潜力与叶片大小呈中等程度负相关，与次级叶脉数目呈强负相关，而与叶柄长度呈正相关。本研究对于评估茶树无性系多样性具有关键意义，同时可为茶树品种改良与育种项目提供更广泛的应用场景。