STUDIES ON DIVERSITY AND HOST PLANT RESISTANCE OF Sclerotium rolfsii SACC. CAUSING COLLAR ROT IN LENTIL
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Date
2021-10-10
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Banda University of Agriculture & Technology, Banda-210001, Uttar Pradesh, India
Abstract
Lentil (Lens culinaris Medik.) is an important and oldest pulse crop. Collar rot caused
by Sclerotium rolfsii is an important disease of lentil. An intensive roving survey was conducted
for the assessing prevalence and incidence of collar rot in two lentil growing districts (Hamirpur
and Banda) of Bundelkhand region of Uttar Pradesh. A total of 44 locations were surveyed and
observed that the disease was prevalent at all the locations. The collar rot incidence ranged from
3.5 to 40%. The mean disease incidence was highest (18%) in Muskara block of Hamirpur district
and lowest (7.62%) in Jaspura block of Banda district. In order to diversity study of collar rot
pathogen a total of fifteen isolates of Sclerotium rolfsii were isolated from diseased plant samples
collected from surveyed locations. It was observed in diversity study of pathogen that all the
isolates of the Sclerotium rolfsii highly diverse in mycelial and sclerotial morphological traits on
PDA medium. Among the mycelial traits significant variations were recorded in colony diameter,
colony colour, type and appearance of colony growth on PDA medium after 72 hrs of incubation
at 27 °C. Most of the isolates were fast growing which recorded 86.33 to 90 mm colony diameter
after 72 hrs of incubation. Based on the colony appearance six isolates were showed sparse, four
isolates showed fluffy and remaining five isolates were showed the dense mycelial growth on
PDA medium. Variation among the isolates on the basis of colony colour was also recorded, that
the isolates were produced extra white, white and dull white colour colonies on PDA medium. The
variability in sclerotial traits of isolates was recorded significantly. The numbers of sclerotia were
highly varied among the isolates and ranged from 131.33 to 663 per plate (90 mm). The isolates
also showed variation in test weight (weight of 100 sclerotia) of sclerotia, ranged from 47.23 mg
to 82.10 mg per hundred sclerotia. The size of sclerotia also varied in different isolates and ranged
from 0.76 mm to 1.72 mm in diameter. The colour of sclerotia was mostly brown to light brown at
maturity. Shape of sclerotia was also varied among the isolates and most of the isolates were
produced spherical to irregular shape sclerotia. The sclerotia in most of the isolates were
distributed in peripheral to scattered manner over the PDA plates. In order to determination of
mycelial compatibility groups (MCG) among the isolates the isolates were paired to each other on
PDA plates and the isolates also paired themselves to ensure self-compatibility. There were 120
combinations of fifteen isolates, out of which only 43 combinations showed compatible reactions
(35.83% of all the combinations) while remaining 77 combinations showed incompatible reaction.
Based on compatible and incompatible reaction three MCGs were distinguished among fifteen
isolates. Fifty genotypes of lentil were evaluated in nethouse and field condition against collar rot.
Out of 50 genotypes five genotypes viz, IPL 5-09-38, ILL-9948, DPL-15, TAL-6 and DPL-62
were showed moderately resistant reaction in both the conditions.
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JITENDRA PAL SHAKYA 2021. STUDIES ON DIVERSITY AND HOST PLANT RESISTANCE OF Sclerotium rolfsii SACC. CAUSING COLLAR ROT IN LENTIL . M.Sc. Thesis. 68p.