Morphology and morphometrical variations of Meloidogyne incognita in Assam

Populations of Meloidogyne incognita were collected from 15 districts of Assam to study the morphological and morphometrical variations. In case of second stage juvenile (J₂) morphological variations exhibited only in tail shape. Larger tail with short hyaline region was observed in Kamrup and Dibrugarh populations. The lip height of J₂ was recorded with 3 μm in most of the population viz., Sonitpur, Kokrajhar, Karbi Anlong, Marigaon, Borpeta and Goalpara. Morphometric characters of J₂ were found moderate to highly variable except the stylet length and lip height (C.V. 2.7420.21%). Perineal pattern of Dhemaji population showed high squarish dorsal arch and weakly formed lateral line was found in Karbi Anglong Population. The AVS and LVS of perineal pattern (C.V. 3.51–11.42%) were found as stable characters, while the length and width of perineal pattern were moderately variable (C.V. 1.0–15.49%). Male populations were found in five district of Assam. Body length (C.V. 5.06–26.68%) and ‘a’ ratio (C.V. 4.44–28.79%) of male were found as highly variable characters, while the stylet length and MB were stable characters (C.V. 4.16–9.52%).