scholarly journals Impact of Agro-met Conditions and Crop Growth Stages on the Progression of Brown Spot Disease in Basmati Rice

2021 ◽  
pp. 59-67
Author(s):  
H. S. Viswanath ◽  
Ramji Singh ◽  
Gopal Singh ◽  
Prashant Mishra ◽  
U. P. Shahi ◽  
...  
Keyword(s):  
Disease Progression ◽  
Negative Correlation ◽  
Significant Negative Correlation ◽  
Brown Spot ◽  
Basmati Rice ◽  
Growth Stages ◽  
Crop Season ◽  
Spot Disease ◽  
Brown Spot Disease ◽  
Crop Growth Stages

The present study was carried out at Crop Research Centre of SVPUAT Meerut, U.P during three cropping seasons i.e. 2018, 2019 and 2020 using basmati rice as test cultivar. The study was primarily focused upon the combined effect of weather parameters and crop growth stages of rice crop on the progression of brown spot disease. It was noticed that disease was first observed at late vegetative stage in every cropping season viz. 2018, 2019 and 2020 and reached its maximum towards maturity phase of the crop by obtaining total AUDPC’S of 1049.3, 1170.74 and 852.6 respectively. A significant negative correlation between weekly percent disease index (PDI) and T-max & T-min was obtained recording correlation coefficients (r) of (- 0.71 & - 0.98), (- 0.88 & - 0.98) and (- 0.63 & - 0.98) during 2018, 2019 and 2020 respectively indicating decline in maximum and minimum temperatures at the terminal stages of the crop can greatly favor disease progression. A non-significant positive correlation was obtained between weekly m-RH and PDI to the end of every crop season. During the year 2020, a highly significant negative correlation was obtained between weekly a-RH and PDI (r = - 0.803) in contrast with the years 2018 (r = - 0.55) and 2019 (r = -0.477) exhibiting non-significant negative correlation which might be the reason for low PDI during the year 2020 due to greater decline in relative humidity to the end of the crop season. Although, a non-significant negative correlation between weekly PDI and RF (rainfall) and partial positive correlation with weekly bright sunshine hours (BSS) was obtained during all three crop seasons, high intermittent rainfall from late vegetative to reproductive stage during 2018 and 2019 might be responsible for large amount of spore dispersal (high inoculum pressure) leading to greater disease progression. The regression model developed using 2018, 2019 and 2020 meteorological data, which was validated with disease severity data of 2019 yielded significant R2 value of 0.98 using observed and predicted values.

scholarly journals Studies on host-selective toxins produced by a pathotype of Alternaria citri causing brown spot disease of mandarins.

1986 ◽  
Vol 50 (6) ◽  
pp. 1597-1606 ◽  
Author(s):  
Yoshiki KONO ◽  
J. M. GARDNER ◽  
Yoshikatsu SUZUKI ◽  
Setsuo TAKEUCHI
Keyword(s):  
Brown Spot ◽  
Spot Disease ◽  
Brown Spot Disease

Brown spot disease in ‘Rocha’ pear Portuguese orchards

2021 ◽  
pp. 335-342
Author(s):  
P. Reis ◽  
C. Rego ◽  
M. Mota ◽  
T. Comporta ◽  
C.M. Oliveira
Keyword(s):  
Brown Spot ◽  
Spot Disease ◽  
Brown Spot Disease

scholarly journals Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Yosep S. Mau ◽  
Antonius Ndiwa ◽  
Shirly Oematan
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Upland Rice ◽  
Brown Spot ◽  
Yield Reduction ◽  
Rice Cultivars ◽  
Rice Varieties ◽  
Resistance Level ◽  
Spot Disease ◽  
Brown Spot Disease

Abstract. Mau YS, Ndiwa ASS, Oematan SS. 2020. Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia. Biodiversitas 21: 1625-1634. Brown spot is one of the most devastating diseases of rice, which could lead to total yield loss. The disease has a worldwide distribution, more specifically in areas where water supply is scarce, most specifically in the dry upland areas. Almost all stages of rice are affected by the disease, where leaves and grains are mostly affected. Considerable differences exist in susceptibility to brown spot among rice varieties, which may cause a large variation in yield loss caused by the disease. Therefore, the resistance level of rice varieties and their yield reduction has to be regularly evaluated and updated. There are only a few reports on the relationship between brown spot severity with yield and yield loss of upland rice, and is even lacking in pigmented upland rice. The objectives of the present study were to assess the brown spot severity and resistance level in pigmented upland rice cultivars from East Nusa Tenggara Province, Indonesia, and to elucidate their relationships with yield and yield reduction. Twenty four pigmented upland rice genotypes were evaluated in the field during May to October 2019, and their disease responses and yields were recorded. Disease severity was observed weekly and used to calculate Area Under the Disease Progress Curve (AUDPC) for comparison among the genotypes. The relationships between disease severity and AUDPC with yield and yield loss were also examined. The results showed significant variation in brown spot severity and AUDPC, ranging from, respectively, 11.11% to 40.70% and 398.42%-days to 1081.30%-days. Yields and yield losses of test genotypes also varied substantially. Yields under diseased-free and diseased plots ranged from, respectively, 2.34 t ha-1 to 6.13 t ha-1 and 1.68 t ha-1 to 3.74 t ha-1 while yield loss was between 10.46% and 56.15%. Six genotypes were moderately resistant, four genotypes were moderately susceptible and 14 genotypes were susceptible to brown spot. Neither disease severity nor AUDPC had a linear relationship with yield but both exhibited positive and linear relationships with yield loss.

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