ROOT-KNOT NEMATODE, MELOIDOGYNE JAVANICA, PATHOTYPE 2, ON FENNEL
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Date
1995
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Publisher
AAU, Anand
Abstract
Experiments on root-knot nematode,. Meloidogyne javanica , Pathotype 2 affecting fennel were conducted to study i, Pathogenicity of M. javanica , Pathotype 2 to determine threshold level in terms of plant growth characters and uptake of N, P, K, Ca, Mg and S nutrients by plants, ii, biochemical changes induced by nematode infection in the crop, ill, histopathological studies to know host-parasite relationship and iv, effect of nematode infection on seed germination, plant growth and crop yield during 1994-95. The salient findings are : i, An inoculum level of 100 J2/plant and above was detrimental to the growth and development of fennel cv. PF 35. Root, soil and total nematode population/plant significantly increased progressively with an increase in nematode population from 10 to 10,000 J2/plant. Nematode reproduction rate was maximum (76.70) in the level of 10 J2/plant and minimum (3.22) in 10,000 J2/plant. ii, Biochemical changes induced by nematode feeding on fennel roots indicated that roots inoculated with 10, 100, 1,000, 5,000 and 10,000 J2/plant had significantly less peroxidase, polyphenoloxidase and total phenol content over control-uninoculated plant roots. ill, Histopathological studies revealed that after invasion, second stage larvae penetrated the epidermal cells and migrated both inter and intracellularly and anchored to the vascular tissues. Giant cells consisted of uneven thickened, unbroken walls, dense cytoplasm and clusters of nuclei. Pathological reaction included abnormal xylem located in the vascular tissues. All nematode stages were found inside the root tissues feeding on vascular region. The healthy tissue showed no change in epidermal cells and cortex region of roots, iv, Study on effect of M. .iavanica. Pathotype 2 on seed germination and plant growth development and root-knot index on fennel cv. PF 35 indicated that nematode infested soil significantly reduced fennel seed germination, plant height, fresh shoot and root weights by 12.30, 29.60, 3.98 and 17.09 % respectively over control-steam sterilized soil. Infested soil had 116.30 % increased root-knot index over control. V, Inoculation of M. javanica, Pathotype 2 at 2000 J2/kg soil significantly decreased plant height and grain yield of fennel cv. PF 35 by 19.83 and 26.51% respectively, while root-knot index and reproduction rate were significantly increased by 59.01 and 58.88 % respectively over control-steam sterilized soil. vi, Application of Dazoraet (Basamid 98 G @ 1 g/pot) significantly increased plant height and grain yield of fennel cv. PF 35 by 18.61 and 36.09 % respectively and root-knot index has significantly, reduced by 59.01 % due to Dazomet application over control-no nematicidal treatment.
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Keywords
Plant Nematology, Agriculture, A Study