Abstract:
Wheat blast disease caused by Magnaporthe oryzae triticum (MoT) has become a serious
constrain in increasing the wheat area of infection and decreasing the cultivable area of
the crops. A survey was conducted in 30 villages of blast infected South-Western wheat
growing region of Bangladesh during January to April, 2019. During the survey at
Meherpur Sadar, Mujibnagar and Chuadanga Sadar Upazilla, the highest incidence and
severity was recorded in cultivar BARI Gom-24 (Pradip) at Kutubpur, Monkhali and
Parkrisnapur village and the lowest incidence and severity was found in BARI Gom-26
and BARI Gom-28 at Pirojpur, Charulia and Bollolpur village. Thirty-five MoT isolates
were isolated, identified and tested their pathogenicity. Growth response and cultural
characteristics of the MoT isolates were done on PDA. In the present study, the highest
radial mycelial growth observed on the isolate CHMoT 09 (25.67 mm) on the 7
days,
CHMoT 06 (56.33 mm), CHMoT 07 (55.83 mm), CHMoT 08 (56.33 mm) and CHMoT
09 (57.00 mm) on the 14
th
days incubation and CHMoT 08 (75.50 mm) on the 30
days
incubation. Based on mycelial growth per day, isolates of M. oryzae triticum were
classified into three cluster groups, cluster I, cluster II, cluster III that indicates the
presence of a morphologically diversified group of pathogens. Aloe vera (Allovera leaf)
extracts and Nigella sativa (Black cumin seeds) extracts @ (1:1 w/v) concentration were
found the most effective botanicals to reduce mycelial growth of M. oryzae triticum
under in-vitro condition. However, this experiment with more plant extracts needs to be
coined out to assess the field efficacy of these botanical extracts with different
concentrations and frequencies in controlling blast disease of wheat.
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