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PATHOGENICITY OF HETERODERA SACCHARI (LUC AND MERNY) AND ITS INTERACTION WITH BOTRYODIPLODIA THEOBROMAE (PAT) ON SOME NERICA RICE CULTIVARS
Published 2013Call Number: Loading…
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INTERACTION OF Meloidogyne incognita WITH Botryodiplodia theobromae ON Manihot esculenta (CASSAVA) AND ITS BIOCONTROL
Published 2014-07Call Number: Loading…
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Page will reload when a filter is selected or excluded.- Botryodiplodia theobromae 2 results 2
- Glomu mosseae 1 results 1
- Heterodera sacchari 1 results 1
- Histopathology 1 results 1
- Meloidogyne incognita 1 results 1
- NERICA rice 1 results 1
- Paecilomyces lilacinus 1 results 1
- Pathogenicity 1 results 1
- Pathogenicity in cassava 1 results 1
- The Cyst Nematode (CN), Heterodera sacchari, is an important pest that causes yield losses of upland rice. NERICA Rice (NR) is a widely-grown upland rice cultivar. Botryodiplodia theobromae (a rot fungus) exists in many agricultural lands and causes yield losses on crops. However, information on the pathogenicity and damage by CN on NR cultivars in Nigeria is scanty. Therefore, pathogenicity of CN on NR cultivars and its interaction with Botryodiplodia theobromae were investigated. Twenty-four upland cultivars were screened for resistance to H. sacchari by inoculating three-week old seedlings with zero and 5000 eggs of H. sacchari. Cyst rating following standard procedure was used to determine resistance/susceptibility. Pathogenicity of H. sacchari was conducted to determine nematode damage on NR1, NR2, NR3, NR8 and NR14 cultivars in pot and field experiments in two cropping seasons. Three-week old seedlings of each cultivar were inoculated in pot experiment at zero, 5000 and 10000 eggs of H. sacchari per pot in four replicates in a 5X3 factorial using Randomized Complete Block Design (RCBD). The field trial was a split-plot experimental design with nematode-treatment as main plot and the five NERICA rice cultivars as sub-plots. Interaction between H. sacchari and B. theobromae on NR was investigated in pot and microplot experiments using standard procedures. Three-week old seedlings of NR1 were inoculated at zero or 5000 eggs of H. sacchari alone, 5x105 spores ml-1 of B. theobromae alone and simultaneous inoculation of H. sacchari + B. theobromae per pot in four replicates in a RCBD. The same treatments were carried out for the seedlings in the microplots (50x50x75) cm. Plants were assessed for growth, yield and nematode-fungal damage. Root sections (14?m) of NR from the interaction experiment were prepared for histopathology studies using standard procedures. Photomicrographs of cell structural integrity and damage were taken. Data were analyzed using descriptive statistics and ANOVA at p=0.05. Twenty-one rice cultivars (seven improved Oryza sativa and 14 NR cultivars were rated susceptible), NR6 and NR8 were rated moderately resistant and CG14 was most resistant. Heterodera sacchari significantly reduced NR growth by 41.8%, root weight by 55.4% and yield by 67.7%. Interaction between H. sacchari and B. theobromae significantly reduced NR growth by 58.8% - 67.3%, root weight by 63.4% - 70.4% and yield by 62.2% - 75.4%, compared to single inoculation with H. sacchari or B. theobromae. Heterodera sacchari infection caused cellular disorganization, compression and disintegration. Syncytia with seven nuclei, were formed close to nematode head seven days after inoculation (DAI). Both CN and B. theobromae developed and reproduced when present on same root tissue. Fruiting bodies of B. theobromae enlarged and ruptured cortical cells and epidermal layer of root during ascospore discharge 7 DAI. Infection of both pathogens revealed dark necrotic regions, cellular compression, disorganization and disintegration. Syncytium was established by the nematode in presence of the fungus 9 DAI. Heterodera sacchari caused significant damage and yield reduction on NERICA Rice cultivars and its interaction with Botryodiplodia theobromae, synergistically reduced growth and yield of rice. However, CG14 was most resistant. 1 results 1
- The Root-Knot Nematode (RKN), Meloidogyne incognita and fungus Botryodiplodia theobromae, are important pests that cause yield losses in cassava and other crops. Chemicals have been used to manage these pests but with undesirable side effects. Information on pathogenicity of M. incognita, its interaction with B. theobromae and its biocontrol in Nigeria is very little. Therefore, pathogenicity of M. incognita on cassava, its interaction with B. theobromae and management with biocontrol agents were investigated. A split–plot experiment was conducted in two cropping seasons with nematode-infested and denematised treatments (main-plot) on five cassava cultivars (sub-plots) to study pathogenicity in both field and pots. Two-week old potted sproutings were inoculated with 0, 1000, 10000 eggs of M. incognita per pot in four replicates in a 5 x 3 factorial experiment. Vegetative Growth (VG), galling index and yield-related traits were assessed using standard procedure. Interaction between M. incognita and B. theobromae on cassava was also investigated in pot and microplot field experiments. Two-week old sproutings of TMS 30572, TME 1 and Ofege cassava cultivars were each inoculated with 0, 1000 and 10000 M. incognita eggs, 5x105 spores mL-1 of B. theobromae and combined inoculation of M. incognita+B. theobromae per pot (r=4). Similar treatments were applied to sproutings in the microplots. Plants were assessed for VG, yield, percentage tuber rot and nematode reproduction. The assessment of Glomus mosseae and Paecilomyces lilacinus solely and in combination in the management of M. incognita was evaluated in pot and field studies following standard procedures. Plants were assessed for VG, yield, galling index and nematode reproduction. Data were analysed using descriptive statistics and ANOVA at p=0.05. Meloidogyne incognita reduced by 35.0%, 30%, 18.8%, 54.3% and 53.0% for plant height, shoot weight, stem diameter, fresh tuber weight and number of tubers, respectively. Galling index increased with increase in inoculum density. In the interaction studies, sole inoculation with M. incognita reduced plant height (15.0%), fresh shoot weight (34.9%), number of tubers (35.6%) and tuber weight (32.0%). Inoculation with B. theobromae alone significantly reduced plant height (9.0%), fresh shoot weight (15.7%), number of tubers (22.7%) and tuber weight (25.0%). Combined effects of M. incognita and B. theobromae reduced plant height (25.6%), fresh shoot weight (44.6%), number of tubers (43.2%), tuber weight (72.2%) and increased tuber rot by 48.1% across cultivars. Paecilomyces lilacinus and G. mosseae reduced M. incognita population by 85.0% and 86.7% respectively; and, when added together, by 60.0%. Galling index was reduced by 66.6% and 66.5% respectively when P. lilacinus and G. mosseae were solely applied and when applied together by 35.7%. The use of P. lilacinus and G. mosseae increased VG by 30.4% and 26.7% and tuber weight by 55.9% and 58.3% respectively. Meloidogyne incognita and Botryodiplodia theobromae reduced the growth, yield and quality of cassava. Applications of Paecilomyces lilacinus and Glomus mosseae have great potential in the management of Meloidogyne incognita in cassava production. 1 results 1
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