Studies on epidemiology, variability and management of bakanae disease (Fusarium moniliforme Sheldon) of aromatic rice (Oryzae sativa L.)
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Date
2023-08-04
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CCSHAU, Hisar
Abstract
Bakanae of aromatic rice is one of the most destructive disease which appear in Haryana and
adjoining states especially in early transplanted rice crop. The present studies were undertaken on
“epidemiology, variability and management of bakanae disease during kharif 2021 to kharif 2022”. A
total of 64 isolates were collected during roveing survey in kharif 2020 and 2021 from commonly
aromatic rice grown area of Haryana state. Isolates were characterized on the basis of cultural and
morphological characteristics on potato dextrose agar (PDA), showed white, milky white to creamy
white colour on surface and cottony to cottony fluffy texture. Three isolates showed macro-conidia
whereas, rest of isolates showed micro-conidia. The macro-conidia size ranged between (22.36-28.09)
× (3.01-4.71) μm in length and breadth, respectively. The size of micro-conidia ranges between (4.80-
9.92) × (1.42-2.71) μm. The growth rate of isolates varied between 12.95-25 mm/48 hrs. Molecular
variability among 26 selected isolates was assessed by using different molecular primers viz. β-tubulin,
Tef 1 α, Vertf and rp 32 & rp 33, SSR, ISSR, URP and RAPD. Out of forty one tested primers, 18
showed amplification and 100 % polymorphism. Among SSR, URP and RAPD, ISSR primers,
polymorphic information content (PIC) values ranged between 0.28-0.99, 0.35-0.39 and 0.30-0.39,
respectively. Cluster analysis divides the 26 isolates into nine groups with the genetic similarity
coefficient of 43.5. Among the biochemical constituents (mg/g of dry mycelium) total sugars, phenols,
free amino acid and protein content varied between 3.77 (FM 53) - 12.08 (FM 63), 3.21 (FM 59) -
11.98 (FM 20), 26.31 (FM 25) - 58.83 (FM 53), 70 (FM 36) - 112 (FM 40), respectively. Amongst
weather parameters during kharif 2021 maximum temperature (Tmax) and relative humidity morning
(RHM) among all seasons showed positive correlation and minimum temperature and wind velocity
showed negative correlation with bakanae per cent disease incidence. Coefficient of determination (R²)
values ranged between 0.85 to 0.99. Among fungicides, carbendazim 50 WP was found most effective
at 50 ppm under lab conditions. Among bioagents evaluated under nursery and field conditions,
Trichoderma viride (WP) showed better results. Out of 46 genotypes screened under artificial
inoculation field conditions, 22 were resistant, 17 were moderately resistant, 4 were susceptible and 3
were highly susceptible. Under nursery conditions, out of 61 genotypes, 35 were resistant, 23 were
moderately resistant, two were susceptible and one was highly susceptible based on two year data.