Morphological and Molecular Characterization of Predominant Plant-Parasitic Nematodes Associated with Pattawia Pineapple-Cultivated Areas in Prachuap Khiri Khan, Thailand.

The predominant plant-parasitic nematodes associated with Pattawia pineapple-cultivated areas were investigated using combined molecular and morphological techniques. In total, 134 soil samples were collected for nematode extraction from the main pineapple crops in 3 districts (Sam Roi Yot, Mueang and Hua Hin) of Prachuap Khiri Khan, Thailand. Based on the morphology, 6 plant-parasitic nematode genera were identified: Rotylenchulus sp., Meloidogyne sp., Helicotylenchus sp., Hoplolaimus sp., Mesocriconema sp. and Pratylenchus sp. The main plant-parasitic nematodes that occurred in Sam Roi Yot and Mueang districts were Rotylenchulus sp. (70.27 and 97.01 %, respectively), while in Hua Hin district, Helicotylenchus sp. (37.73 %) was dominant. Based on molecular identification, nucleotide sequence comparisons and the phylogenetic tree analyses based on the 18S and 28S rRNA genes revealed the species of the nematodes were R. reniformis and H. dihystera, showing 99 % identity with the nematode populations from Japan and China, respectively. Notably, the morphometric and morphological characters also identified these 2 species correctly; however, this technique required more time and may be less accurate. While R. reniformis has been identified as a common species in pineapple fields in the USA, India, Kenya, the Philippines and Nigeria, the current study was the 1st to report H. dihystera isolated from soil in Pattawia pineapple crops in Thailand. [ABSTRACT FROM AUTHOR]