Please use this identifier to cite or link to this item: http://krishikosh.egranth.ac.in/handle/1/5810043717
Authors: Patel, Nautam B.
Advisor: Patel, D. J.
Title: LESION NEMATODE, Pratylenchus zeae GRAHAM, 1951 ON MAIZE
Publisher: AAU, Anand
Language: en
Type: Thesis
Agrotags: Nematology
A STUDY
Keywords: LESION NEMATODE, Pratylenchus zeae GRAHAM, 1951 ON MAIZE
Abstract: Studies on lesion nematode, Pratylenchus zeae, affecting maize cv. Farm Sameri were carried out with respect to i, pathogenicity of P. zeae on maize cv. Farm Sameri to determine threshold level in terms of plant growth characters, nematode reproduction and uptake of N, P, K, Ca, Mg and S nutrients by plant; ii, biochemical changes induced by nematode infection in crop; iii, histopathological studies to know host-parasite relationship in crop; iv, effect of nematode infection on seed germination, seedling emergence, plant growth development and nematode reproduction in-crop in pots; v, estimation of avoidable yield losses due to nematode infection in crop in pots and field conditions; vi, interaction between nematode and stalk rot fungus in crop and vii, evaluation of different maize hybrids/varieties against P. zeae during 1996-97 and 1997- 98. The salient findings are as under : i, An inoculum level of 1,000 and above nematodes/plant significantly decreased plant height, fresh shoot and root weights. Soil, root and total nematode population build up/plant progressively increased with an increase in nematode inoculum levels from 0 to 10,000 nematodes/plant. Nematode reproduction rate decreased with an increase in inoculum levels. It was maximum of 66.00 times in the level of 10 nematodes/plant and minimum of 5.50 times in the level of 10,000 nematodes/plant. Uptake of various nutrients viz., nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulphur (S) significantly reduced from the level of 500 to 10,000 nematodes/plant except P which significantly reduced from the levels of 1,000 to 10,000 nematodes/plant. Control (uninoculated) plants had significantly more uptake of all the nutrients over other treatments. ii. Biochemical changes induced by nem.atode infection in maize revealed that peroxidase and total phenol contents progressively increased, whereas polyphenol oxidase subsequently decreased with an increase in nematode inoculum levels from 10 to 10,000 nematodes/plant over control (uninoculated) plant roots. iii, Histopathological and cytological studies to know host-parasite relationship indicated that after invasion, nematode penetrated epidermal cells and finally reached the cortex region. Because of migratory in feeding habit, cavities were formed in the cortex region and female laid eggs within cavities. During nematode feeding, they also secreted some enzymes which might have produced brown lesions on the roots. iv, Study on effect of P. zeae on seed germination, over all plant growth development, leaf chlorophyll contents and nematode reproduction on maize cv. Farm Sameri indicated non-significant differences for seed germination/emergence ' among nematode infection and control (uninoculated/sterilized soil). Nematode infested soil significantly reduced maize plant height, fresh shoot & root weights and leaf chlorophyll a, b & total chlorophyll contents by 51.02, 47.01, 71.11, 22.32, 41.18 and 28.31 respectively over control-steam sterilized soils. Nematode population also increased from 14,080 to 1,36,5 U/8 kg soil giving reproduction rate of 9.7 times in 90 days. V, Experiment on estimation of avoidable yield losses in maize cv. Farm Sameri due to lesion nematode indicated that - a. inoculation of 3,000 nematodes/plant significantly decreased plant height, stem girth, fresh shoot and root weights by 46.43, 29.55, 67.28 and 56.01 % giving cent percent grain yield loss respectively over control-no nematode inoculation. Nematode population increased from 3,000 to 45,299/4 kg soil giving reproduction rate of 15.10 times. b. application of phenamiphos @ 2 kg/ha in two equal splits at the time of seeding and 30 DAS significantly increased plant height, fresh shoot & root weights, cob length, grain, stover and straw yields to the extent of 17.95, 39.19, 46.60, 25.45, 32.16, 33.90 and 24.69 % respectively with significant reduction in RLI, final soil and root nematode population by 30.96, 49.60 and 48.72 % respectively over control. vi. Study on interaction between P. zeae (N) and F. moniliforme (F) on maize cv. Farm Sameri revealed that plant height, fresh shoot and root weights were significantly less in N-F treatment followed by N+F, N alone treatments. N alone treatment produced maximum number of soil, root and total nematode population with reproduction rate of 10.27 times followed by N-F and N+F treatments having 7.57 and 6.29 times reproduction rates respectively. The N-F treatment recorded maximum plant mortality of 42.86 % due to stalk rot disease over other treatments and disease appeared one week earlier than N+F treatment. Similarly, N+F and F-N treatments also recorded 35.71 and 14.29 % plant mortality respectively. The treatment of F alone had no plant mortality possibly due to weak parasitism of fungus on the host. vii. Evaluation of different maize hybrids/varieties for locating source(s) of resistance against lesion nematode revealed that all 13 hybrids/varieties viz., IC 9001, 9002, 9004, 9005, 9010 & 9011; composite 74; Gujarat Maize 1 & 2; Cargill 633, 501 & 520 A and Farm Sameri recorded susceptible reaction to P. zeae.
Subject: Nematology
Theme: LESION NEMATODE, Pratylenchus zeae GRAHAM, 1951 ON MAIZE
Research Problem: LESION NEMATODE, Pratylenchus zeae GRAHAM, 1951 ON MAIZE
These Type: Ph.D
Issue Date: 1999
Appears in Collections:Theses

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