Phenotypic diversity of Sri Lankan rubber clones at their immature stage

Systematic identification of morphological markers useful in the characterization of rubber clones has played a vital role in the crop management system. Although they do not exhibit highly distinct variations, there are certain minor, but more or less stable differences, which can be used for identification. This study was undertaken to estimate morphological diversity present in the Sri Lankan rubber clones at their immature stage and to determine the importance of morphological markers in categorizing different clones into distinct groups. Thirty clones were characterized using 29 standardized morphological descriptors. Principal component analysis (PCA) and Cluster analysis based on first twelve principal components that accounted for 85% of the total phenotypic variation distinguish 30 clones into six major clusters. Out of 29 descriptors, 27 were informative and contributed significantly to the variation among the clones selected. This study identifies the morphological descriptors that are most important for characterization of rubber clones grown in Sri Lanka.