scholarly journals Field management of Phytophthora blight disease of cocoyam Colocasia esculenta L.) With spray regimes of selected fungicides in Nsukka, south eastern Nigeria

Agro-Science ◽  
2016 ◽  
Vol 14 (2) ◽  
pp. 36
Author(s):  
TE Omeje ◽  
KI Ugwuoke ◽  
SC Aba ◽  
SC Eze ◽  
SI Ogwulumba ◽  
...  
Keyword(s):  
Colocasia Esculenta ◽  
South Eastern ◽  
Field Management ◽  
Blight Disease ◽  
Spray Regimes

scholarly journals Role of Ascorbate–Glutathione (AsA–GSH) Pathways in Phytophthora Leaf Blight Disease Resistance in Taro (Colocasia esculenta L. Schott)

2020 ◽  
pp. 66-75
Author(s):  
Yumnam Indrani Devi ◽  
Madhumita Dasgupta ◽  
Joydip Mandal ◽  
Manas Ranjan Sahoo
Keyword(s):  
Defense Mechanisms ◽  
Colocasia Esculenta ◽  
Leaf Blight ◽  
Monodehydroascorbate Reductase ◽  
Vegetable Crops ◽  
Resistant Lines ◽  
Infection Spot ◽  
Reliable Parameter ◽  
Plant Pathogen Interaction ◽  
Blight Disease

Taro (Colocasia esculenta L. Schott) is one of the important staple vegetable crops grown worldwide for its nutritious corms, leaves, and pseudostems. Taro invaded by leaf blight disease caused by Phytophthora colocasiae Racib. (Pc) resulted in 50% yield loss. On the other hand, inherent defense mechanisms of taro encounter the invaders to protect the plant from Pc invasion. The ascorbate–glutathione (AsA–GSH) pathways play an essential role in scavenging reactive oxygen species (ROS), a common phenomenon in plant–pathogen interaction. The present study focused on AsA–GSH regulations of thirty genotypes of taro under induced Pc infection. RCMC–5, among the tested taro genotypes, registered consistently higher induction of AsA, GSH, Ascorbate peroxidase (APX), monodehydroascorbate reductase (MDAR), and dehydroascorbate reductase (DHAR) to encounter the Pc infection and overproduction of ROS. However, glutathione reductase (GR) was more prominent in DP–25, Jhankri, and TSL. AsA–GSH encounters the ROS overproduction, which was confirmed with lower H2O2 (0.20 µM g–1 FW) and malondialdehyde (MDA) content (20.10 nM g–1 FW) in resistant genotypes (RCMC–5) subsequently resulted in lower Pc infection (spot diameter, <2.0 cm and sporangia, <2). RCMC–5 could be one of the lines of interest in taro breeding programs for developing Pc resistant lines. AsA–GSH cycle could be a reliable parameter while selecting resistant lines for augmenting breeding strategies in taro against Phytophthora.

scholarly journals Severity of Phytophthora leaf blight disease and susceptibility of two local varieties of Colocasia to Phytophthora colocasiae Raciborski in Nsukka zone of South Eastern Nigeria

Bio-Research ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 1286-1296
Author(s):  
Faustina Njideka Ugwuja ◽  
Chiemeka Nwakaego Onaebi ◽  
Nneka Virginia Chiejina ◽  
Kelvin Ikechukwu Ugwuoke
Keyword(s):  
Disease Severity ◽  
Leaf Surface ◽  
Average Diameter ◽  
Colocasia Esculenta ◽  
Leaf Blight ◽  
Test Results ◽  
Local Varieties ◽  
Potted Plants ◽  
Phytophthora Colocasiae ◽  
Blight Disease

Leaf-blight disease of Colocasia caused by Phytophthora colocasiae Raciborski has been a serious impediment to cocoyam production in Nigeria. Disease severity and susceptibility of the two most cultivated local varieties “Ugwuta” (Colocasia esculenta var. antiquorum) and “Nkashi Colocasia esculenta var. esculenta) were investigated. Disease severity was visually estimated as the percentage leaf surface affected by blight, lesion or lesion-related chlorosis for each leaf of a plant using a seven-point scale of 0, 5, 10, 25, 50, 75 and 100% in three locations: Ede-Oballa, Nsukka Urban and Obukpa. Susceptibility was assessed on 2 months old potted plants of each variety inoculated with a 7-day old culture of P. colocasiae. Diameters of lesions on inoculated leaves were recorded from the 3rd - 8th day after inoculation.  Data on severity were subjected to ANOVA and susceptibility of the varieties was compared with t-test. Results revealed significant LSD=4.96 (0.05) and varying degrees of leaf blight severity among varieties and locations. Variety antiquorum had significantly higher severities of 42.08, 46.40 and 47.42% at Ede-Oballa, Nsukka Urban and Obukpa respectively, compared to 34.85, 36.55 and 28.19% recorded by var. esculenta at these locations, respectively. Similarly, var. antiquorum had greater lesion diameter ranging from 0.65±0.07 cm - 3.70±0.14 cm and average diameter of 2.4±0.16cm compared to var. esculenta which had 0.41±0.14cm - 3.12±0.19 cm and average diameter of 1.80±0.16. This research has shown that varieties and locations affect the severity and susceptibility of Phytophthora leaf blight disease. This could be a guide to farmers having known that var. esculenta is less severe to Phytophthora leaf blight disease.

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