STUDIES ON VIRAL DISEASES INFECTING GROUNDNUT (Arachis hypogaea L.)
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Date
2022-08-11
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guntur
Abstract
The present investigation on “Studies on viral diseases infecting groundnut (Arachis hypogaea L.) was carried out at Agricultural College, Bapatla, Guntur district, Andhra Pradesh during kharif and rabi 2020-21.
Roving survey was conducted in two major groundnut growing districts of Andhra Pradesh viz., Guntur and Prakasam which falls under Krishna-Godavari zone on the basis of agroclimatic zones during kharif and rabi 2020-21 revealed the incidence of peanut stem necrosis disease (PSND) caused by Tobacco streak virus in the range of 2.0-11.5% and 0.0-7.7% respectively and incidence of groundnut bud necrosis disease (GBND) caused by Groundnut bud necrosis virus in the range of 0.0-4.6% and 0.0-3.25% respectively during kharif 2020-21.
In rabi 2020-21, incidence of PSND was in the range of 0.0-1.75% in Guntur district and no incidence was recorded from Prakasam district, per cent incidence of GBND was in the range of 0.0-12.45% and 0.0-9.9% in Guntur and Prakasam districts respectively.
Under field conditions, symptoms of peanut stem necrosis disease (PSND) appeared as localized necrotic spots which later got spread to petiole, bud and stem as continuous necrotic streaks and eventually led to the death of the plant. Groundnut bud necrosis disease symptoms appeared as mild chlorotic mottle or spots which later developed into chlorotic rings and necrotic rings on young quadrifoliate leaves of groundnut. Further, the necrosis extended to petiole and to the growing terminal buds, finally to the stem and resulted in proliferation of axillary shoots and stunting.
Mechanical sap inoculations of representative TSV isolate from groundnut, TSV-Karlapelm on to cowpea (Vigna ungiculata cv. PUSA KOMAL) exhibited chlorotic and necrotic spots within 3-5 days of post-inoculation while representative GBNV isolate from groundnut, GBNV-Bapatla (GBNV-GN-INDBPT) exhibited chlorotic spots and distinct chlorotic rings within 4-7 days of post inoculation.
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The partial coat protein (CP) gene of representative TSV-BPT-KP groundnut isolate shared a wide range of nucleotide identities (79.9-98.7%) with the isolates reported globally. It shared 98.1-98.7% nucleotide similarities with groundnut TSV isolates and 97.9-98.7% nucleotide similarities with other crop TSV isolates from India.
The partial movement protein (MP) gene of representative TSV-GN-INDKP groundnut isolate shared a wide range of nucleotide identities (87.4-99.2%) with the isolates reported globally. It shared 98.9-99.2% nucleotide similarities with groundnut TSV isolates and 95.1-99.2% nucleotide similarities with other crop TSV isolates from India.
The partial nucleocapsid (N) protein gene of the present study isolate (GBNV-GN-INDBPT) shared a wide range of nucleotide identity (86.2-98.6%) with other GBNV isolates reported from different crops and locations. GBNV-GN-INDBPT isolate shared 97.0-97.2% nucleotide similarities with other groundnut isolates and 86.2-98.6% nucleotide similarities with other crop GBNV isolates from India.
Seed treatment with thiamethoxam @ 2 g kg-1 seed along with two foliar sprays of thiamethoxam 25 WG @ 0.2 g l-1 at 20 DAS and 45 DAS recorded significantly low incidence of PSND, GBND, population of thrips per terminal bud and also improved shoot length, root length, dry pod yield, number of pods per plant, 100 seed weight, shelling percentage and it was found economical.
Description
STUDIES ON VIRAL DISEASES
INFECTING GROUNDNUT
(Arachis hypogaea L.)