VARIABILITY IN Fusarium oxysporum f.sp. udum CAUSING WILT OF PIGEON PEA AND ITS MANAGEMENT
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Date
2018
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Birsa Agricultural University, Ranchi, Jharkhand-6
Abstract
The present investigation was carried out in the research farm as well as
laboratory of Birsa Agricultural University, Kanke, Ranchi on variability in Fusarium
oxysporum f.sp. udum causing wilt of Pigeonpea and its management. The systematic
investigation revealed that wilt disease in Pigeonpea was found to be infected with
Fusarium oxysporum f.sp. udum at all ten locations surveyed in 2015-16 and 2016-17.
Maximum wilt percentage was found at Bukru (32.14 %) followed by Kanadu (29.40 %)
and Ranchi BAU (28.63 %). After conducting elaborate survey at 10 locations, forty
isolates were collected for studying variations among isolates characters. To identify
Fusarium pathogen as it’s actual casual agent for the disease pathogenicity test was
conducted by using different effective isolates (Isolate-1, 14, 35). It clearly revealed that
Fusarium oxysporum f.sp. udum is the cause for wilt disease in Pigeonpea.
Morphological studies of Fusarium oxysporum f.sp. udum revealed that the dimensions
of macro condia, micro conidia and chlamydospores shows larger variations among
different isolates. The cultural characters observed on PDA medium and the mycelium
colour was in white and pinkish at the center with dense to fluffy growth. The size of
mycelial width varied from 3 μm (Fou-Bor -4) to 6.32 μm (Fou – Ran - 4). Where as
microconidia were small, oval in shape and hyaline in colour, unicellular or with one or
two septa, and measures in the range of size between 6.00 × 2.10 μm (Fou-Ran- 4) to
10.80 × 3.00 μm (Fou- Kok-1). The macroconidia were long, curved, sickle shaped,
pointed at the tip, hyaline in colour and knotched at the base, septated (2-4 septa) and
measured between 19.05 × 3.25 μm (Fou- Hoc-4) to 28.70 × 2.50 μm (Fou- Kok-1).
Chlamydospores with spherical in shape and hyaline in colour and it’s dimensions also
varied in all 40 isolates of the pathogen. Chlamydospores dimension varied from 8.20 ×
7.92 μm (Fou- Buk – 2) to 11.35 × 8.20 μm (Fou-Nag-3). Spore density also varied
between conidia per ml of culture under 10 x microscopic field, it is varied for macro
conidia in the range of 6 to 13, micro conidia it is between 20 to 42 and chlamydospores
it is between 2 to 8 number per ml. Among all the four different semi solid media
maximum radial growth 72.90 mm for Fou-Ran-1was observed on PDA medium. All
forty isolates performed well on PDA medium compared with remaining ones. After
their growth different spores counting was taken under 10x microscopic field. It was also
observed that there is a great variation in sporulation among isolates on different media
and conidial characteristics.
Among four liquid media, maximum and fastest mycelial growth was obtained in
PDA medium followed by Richards medium, Czapeks medium, & Martins medium. In
PDA liquid media isolate Fou-Ran-1 given maximum mycelial dry weight that is 470
mg. After in detailed study of all forty isolates regarding their cultural, morphological
studies these isolates are grouped into different categories based on criteria like size of
macro and micro conidia, septation of macro condia, their growing speed on different
semi solid mediums and number of spores under 10x microscopic field. Out of 19
medium entries most of them showed moderately resistant to wilt disease, in 43 late
entries, 5 entries namely MA-6, PT0012(C), WRGE 102, CRG9701, WRGE 248 showed
resistance against wilt disease, remaining most of varieties moderately resistant to wilt
disease. In host differential reaction, ICP8868, BDN-2, BAHAR genotypes showed same
reaction to the three different effective isolates (Isolate – 1, 14, 35), and these are
grouped under variant 3 based on previous experiments results. In Fungicidal trail Saaf
performed well against wilt disease both in lab and field conditions. In case of organic
amendments (cakes) Neem+Mustard cake performed well in both lab and field
conditions against wilt disease of Pigeonpea. In bioassay trial of bioagents against wilt
disease of Pigeonpea Trichoderma viride performed well in both In-vitro and In-vivo
conditions.
Description
VARIABILITY IN Fusarium oxysporum f.sp. udum CAUSING WILT OF PIGEON PEA AND ITS MANAGEMENT
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