Morphology and molecular taxonomy of endoparasitic nematodes associated with Dioscorea spp. in Jiangxi and Shandong Provinces, China: With special reference to Pratylenchus coffeae

Yam (Dioscorea spp.) is an economically important tuber crop in China, yet the identity, relative abundance, and molecular characterization of the dominant endoparasitic nematode taxa constraining its production remain insufficiently documented. Rhizosphere soil (n = 110) and yam tubers (n = 48) were sampled from nine localities across Jiangxi and Shandong provinces between April 2020 and January 2021. Community structure was quantified using prominence value (PV), mean population density (MPD), and frequency of occurrence (FO). Morphological identification used standard taxonomic keys and light microscopy for the primary focal taxon, Pratylenchus coffeae. Species-level confirmation employed PCR amplification of the internal transcribed spacer (ITS) and D2–D3 expansion segment of 28S ribosomal DNA (rDNA), followed by Bayesian phylogenetic inference, with full morpho-molecular characterization applied to P. coffeae as the principal endoparasitic taxon and supporting molecular confirmation provided for co-occurring taxa. Three primary endoparasitic taxa were recovered: Pratylenchus coffeae was the most abundant and prominent endoparasitic nematode recovered from yam tubers, followed by M. incognita, with R. reniformis recovered at comparatively low abundance; P. coffeae likewise dominated the rhizosphere soil community. At the aggregate level, Pratylenchus coffeae was the most prominent endoparasitic nematode across surveyed Chinese yam systems, surpassing M. incognita in both prominence value and frequency of occurrence. However, dominance patterns varied between provinces: P. coffeae was overwhelmingly prevalent in Jiangxi, while M. incognita dominated in Shandong. Thus, no single species is the principal endoparasite across both provinces. This study delivers the first molecularly verified baseline for the prominent endoparasitic nematode complex of Chinese yams, providing a replicable diagnostic framework for surveillance, phytosanitary monitoring, and integrated pest management.