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Morphological and Morphometric variations of Genus, Paratylenchus and Macroposthonia in Assam
(AAU, Jorhat, 2017-07) Hazarika, Namita; Das, Debanand
The present investigations were carried out to study the morphological and morphometric variation of genus Paratylenchus and Macroposthonia from Upper Brahmaputra Valley Zone of Assam. Altogether 354 soil samples were collected from four districts of Upper Brahmaputra Valley Zone and Macroposthonia viz., Jorhat, Golaghat, Sivasagar and Dibrugarh from the rhizosphere of rice, maize, brinjal, banana, citrus and tea. The population of both the genera collected from four districts were identified as Paratylenchus curvitatus and Macroposthonia onostris. The present study revealed that ‘V’ ratio and stylet length were the stable characters (C.V. 1.16-4.89%) for Paratylenchus curvitatus while, body length, a, b, lip height and lip width, MB , basal bulb width, lip width are the least variable characters (C.V. 4.17-12%); c, c´, basal bulb are moderately variable character (C.V. 10.53-20.50%). The study on morphometric and allometric variations of Macroposthonia onostris from Upper Brahmaputra Valley Zone of Assam concludes that V ratio and MB ratio were the stable characters (C.V. 0.55-7.32%) for M. onostris while a, b c, c´, lip annules, Roes, Rex, Rv, Ran, are the moderately variable characters (C.V. 2.29-18.82%). Body length, R, Rst, Rvan are highly variable characters (C.V. 6.37-36.93%) for M. onostris.