South Western Ghats of India: A niche of clove (Syzygium aromaticum (L.) Merr. & Perry) diversity

The survey conducted across major clove (Syzygium aromaticum (L.) Merr. & Perry) growing regions of the South Western Ghats of India, especially in the states of Kerala and Tamil Nadu, identified thirty accessions with distinct characteristics and superior yield. Clove accessions were characterized based on twenty-one qualitative and twelve quantitative traits. Significant variations were observed among fifteen qualitative characters with predominant traits including elliptical canopy shape, semi-erect branching pattern, leaf lamina and its apex, mid-bud forming season, clustering pattern of flower, bud size, fruit, and seed shape. The dendrogram constructed using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) grouped thirty accessions into five major clusters at a genetic similarity of 73%, with Accession 19 identified as unique. Principal component analysis of twelve quantitative characters revealed three component groups, explaining 70.85% of the total variance. The score plot generated from the principal component loading grouped the accessions into eighteen clusters. A minimal dataset comprising four characters, namely plant height, canopy spread in East-West direction, number of inflorescences per square meter, and mature bud length, was generated. Observations on both qualitative traits and the minimum data set facilitated the identification of ideotypes. The geographical location was not found to influence genetic diversity significantly.