Journal of Basic and Applied Research International

Black pepper (Piper nigrum L.) is an economically important spice crop in tropical regions, yet cultivar-level palynological differentiation remains poorly explored. The present study investigates the qualitative and quantitative pollen morphometrics of six Panniyur cultivars (Panniyur 1 to Panniyur 6) cultivated in the southern Western Ghats of Kerala, India, using scanning electron microscopy (SEM) integrated with multivariate statistical analyses. Pollen samples collected during the flowering season (May - June) were processed through standard acetolysis and SEM preparation protocols. Qualitative observations revealed conserved spheroidal to subspheroidal, inaperturate pollen grains with microreticulate exine ornamentation across all cultivars. However, quantitative measurements of polar axis, equatorial diameter, exine thickness, lumina diameter, muri thickness, and ornamentation density demonstrated significant inter-varietal variation (p < 0.05), except for the P/E ratio. Descriptive statistics indicated greater variability in exine architectural traits compared to overall pollen size. Principal Component Analysis explained 97.2% of cumulative variance, with exine thickness and ornamentation density contributing most strongly to cultivar separation. Hierarchical cluster analysis (Ward’s method) grouped cultivars into two major clusters, while Discriminant Function Analysis achieved complete classification accuracy under the applied model. The congruence of univariate and multivariate results highlights the diagnostic potential of exine micro-architecture for cultivar-level discrimination. The study underscores the value of SEM-based quantitative palynology as a supplementary tool for varietal authentication and taxonomic refinement in Piper nigrum.