Research article · 2025 · Full text
International Journal of Agriculture and Food ScienceEvaluation of cowpea varieties/genotypes against root rot incited by Rhizoctonia bataticola
Volume 7(12) · Pages 218–220 · DOI: 10.33545/2664844x.2025.v7.i12c.1046 ↗
Research areasAgricultural pest management studiesPlant Disease Resistance and GeneticsHumic Substances and Bio-Organic Studies
Abstract
Author-writtenCowpea [Vigna unguiculata (L.) Walp] (diploid, 2n=22) is an annual legume crop. Cowpea is a member of family Fabaceae. Cowpea is attacked by viruses, bacteria and fungi which causes many diseases. Root rot caused by Rhizoctonia bataticola (Taub.) Butler [Macrophomina phaseolina (Tassi.) Goid] is considered as one of the most serious diseases of cowpea. The characteristic symptom of root rot is leaf yellowing, followed by defoliation within two to three days. The infected stems and leaves become dry, brittle and straw colored. The plants show wilting and necrosis symptoms resulting from the pathogen’s vascular bundles blockage and secretion of toxic substances. Fifteen varieties/genotypes of cowpea received from RARI, Durgapura were evaluated against root rot under field condition during kharif 2023. The screening and varieties/genotypes were maintained under field condition with Randomized Block Design (RBD) and observations were recorded in which None of these were found immune or resistant to root rot. CSP 23-10, CPP 22-18, CPP 22-9, CPP 22-8 were observed susceptible, CPP 22-10, CPP 23-4, CPP 22-21, CPP 22-20, CPP 22-3 were found moderately susceptible, CPP 22-5, CPP 22-11, CPP 22-15, CPP 22-12, CPP 22-2, CPP 22-13 were observed moderately resistant and local cultivar (Check) were found highly susceptible.
Summary
Source-checkedPlain-language reading of the full paper, prepared with AI and checked against the text. Each point links to the authors' own words.
Why it matters
- Cowpea is an annual legume crop valued for its early maturity and high nutritional content, earning it the nickname “poor man’s meat”. View evidence ↗
- Root rot, caused by the fungus Rhizoctonia bataticola, is one of the most severe diseases affecting cowpea crops. View evidence ↗
- The disease is characterized by leaf yellowing and defoliation within two to three days, leaving stems and leaves dry and straw-colored. View evidence ↗
The question
- The study aimed to identify cowpea varieties or genotypes that exhibit resistance to Rhizoctonia bataticola under field conditions. View evidence ↗
What they did
- Fifteen cowpea varieties/genotypes from RARI, Durgapura were evaluated in the field during the kharif 2023 season. View evidence ↗
- The field was inoculated before sowing using a pathogen inoculum multiplied on a sorghum medium. View evidence ↗
- The experiment utilized a Randomized Block Design (RBD) to maintain and screen the varieties. View evidence ↗
- Disease incidence was recorded 50 days after sowing to categorize the reaction of each variety. View evidence ↗
- The researchers used Wheeler's (1969) formula to calculate the Percent Disease Incidence (PDI). View evidence ↗
What they found
- None of the fifteen screened cowpea varieties or genotypes were found to be immune or resistant to root rot. View evidence ↗
- Six genotypes (CPP 22-5, CPP 22-11, CPP 22-15, CPP 22-12, CPP 22-2, and CPP 22-13) were categorized as moderately resistant, with disease incidence between 10.1% and 20%. View evidence ↗
- Five genotypes (CPP 22-10, CPP 23-4, CPP 22-21, CPP 22-20, and CPP 22-3) were moderately susceptible, showing disease incidence from 20.1% to 30%. View evidence ↗
- Four genotypes (CSP 23-10, CPP 22-18, CPP 22-9, and CPP 22-8) were found susceptible, with disease incidence exceeding 30%. View evidence ↗
- The control group exhibited the highest disease incidence at 51.60%. View evidence ↗
What it means
- The authors concluded that while no cultivars were fully immune or resistant, the screened genotypes ranged from moderately resistant to susceptible. View evidence ↗
Visual summary
1 visualsIllustrations explain the paper; they do not show study data.
Categorization of Cowpea Genotypes by Disease Reaction
AI-generated conceptual illustration (cowpea plants). It explains the idea and does not show study data.
View source evidence ↗Figures & tables
From the original paper
Table 2
Table 3
Table 1
Table 4
Figure 1Introduction
Cowpea [Vigna unguiculata (L.) Walp] (diploid, 2n=22) is an annual legume crop. It is also known as lobia, southern pea, black eye pea, crowder pea, barbati, china pea, cowgram etc. Cowpea is a member of family Fabaceae. It is also known as "poor man's meat" due to it's high nutritional value and early maturity. Cowpea is a multipurpose crop which is used as pulse, vegetable, forage, fodder, green manure and generally grown as an intercrop with millets such as sorghum for either human or livestock consumption. Cowpea is a significant legume and hay crop in many tropical and subtropical region [4] and an important component of cropping system grown as catch crop, mulch crop, intercrop, mixed crop and green manure crop. Cowpea is a self-pollinated crop and has nitrogen fixation ability which improve soil fertility and consequently helps to increase the yield of cereals when grown in rotation. It is an annual herb with strong principal root and spreading lateral roots in surface soil. The roots have large number of nodules with Bradyrhizobiuim sp which is the symbiotic nodular bacteria that fixes the atmospheric nitrogen. Cowpea is attacked by viruses, bacteria and fungi which causes many diseases [3] . Root rot caused by Rhizoctonia bataticola (Taub.) Butler [Macrophomina phaseolina (Tassi.) Goid] is considered as one of the most serious diseases of cowpea. Rhizoctonia bataticola [Macrophomina phaseolina) (Tassi.) Goid] fungus is mainly a soil borne in nature with wide range of host and it can survive under the soil as saprophyte up to 15 years. The fungus causes high yield losses in the pulses, oilseeds and vegetable crops and produces different symptoms like root rot, charcoal rot, stem and root rot, seedling blight and ashy stem blight. The fungus is a facultative parasite capable of living saprophytically on dead organic tissue, mostly on many of its natural hosts producing microsclerotia, which produces pycnidia. When atmospheric temperature is above 30 °C and the pycnidiospores remain viable for over a year since the fungus attack wide range of plant species [1] . The severity of Rhizoctonia bataticola depends on the population of sclerotia present in the soil. Microsclerotia produce germ tube and penetrate through natural openings in vascular tissues colonization take place [2] .
International Journal of Agriculture and Food Science https://www.agriculturaljournals.com
The most characteristic symptom of root rot was yellowing of the leaves and within two of three days these leaves may drop off. The plant may show wilt within a week and necrotic symptoms due to blockage of vascular bundles with microsclerotia and secretion of toxic substances [6] . The dark lesions may be seen on the bark at ground level. If the plants are pulled out from the soil and examined the plant, the basal stem and main roots show the symptoms of root rot. In advanced stage sclerotial bodies which is scattered may be seen on the affected tissues [7] . Management of root rot caused by Rhizoctonia bataticola (Macrophomina phaseolina) is challenging due to the pathogen's polyphagous nature and ability to survive in the soil through its resting structures. Fungicides are expensive and harmful to the environment, making them a less desirable control option. Host plant resistance is a more economical and environmentally friendly approach to the management of root rot. Management strategies of this disease include, Varietal screening which is the systematic process of evaluating different crop varieties/ genotypes to identify those that possess a superior level of resistance or tolerance to a specific plant disease or pathogen. It is a foundational and highly sustainable component of modern plant disease management, particularly within an Integrated Pest Management (IPM) framework. Ecofriendly approaches to suppressing and destroying of disease.
Material Method Screening of varieties/genotypes against root rot of cowpea
Fifteen varieties/genotypes of cowpea received from RARI, Durgapura were evaluated against root rot under field condition during kharif 2023. Inoculum multiplied on sorghum medium was applied in the field. Inoculum were added before sowing. The screening and varieties/genotypes were maintained under field condition with Randomized Block Design (RBD) and observations were recorded. On the basis of disease incidence and varieties/genotypes were categorized according to their reaction against the disease as per criterion. Percent disease incidence (PDI) was recorded by using the formula given by Wheeler (1969) No. of infected plants Percent disease incidence (PDI) = - ---------------------------------X 100 Total no. of plants
Result
Result
Screening of varieties/genotypes against root rot of cowpea
An experiment was conducted under field conditions to find out the resistance varieties/genotypes against Rhizoctonia bataticola (Macrophomina phaseolina). Observation was recorded after 50 days after sowing on the basis of disease incidence and varieties/ genotypes were categorized according to their reaction against the root rot disease as per criterion
Conclusion
Fifteen varieties/genotypes were screened against Rhizoctonia bataticola under artificial conditions. None of cultivars found immune or resistant to root rot of cowpea while others were moderately susceptible, moderately resistant to susceptible.
Figures and tables from the paper
| Category | Per cent disease incidence |
|---|---|
| Immune | 0 % |
| Resistant | 0.1-10% |
| Moderately resistant | 10.1-20% |
| Moderately susceptible | 20.1-30% |
| Susceptible | More than 30% |
Table text extracted from the original PDF; superscript letters are shown inline. The original table image is below.
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| S. No. | Name of varieties/ genotypes | Percent Disease incidence* | Reaction of varieties/ genotypes |
|---|---|---|---|
| 1 | CSP 23-10 | 34.60 (36.00) | S |
| 2 | CPP 22-18 | 36.53 (37.16) | S |
| 3 | CPP 22-9 | 31.83 (34.32) | S |
| 4 | CPP 22-10 | 24.30 (29.49) | MS |
| 5 | CPP 23-4 | 23.43 (28.92) | MS |
| 6 | CPP 22-5 | 18.33 (25.32) | MR |
| 7 | CPP 22-11 | 16.86 (24.21) | MR |
| 8 | CPP 22-15 | 15.73 (23.35) | MR |
| 9 | CPP 22-21 | 26.90 (31.21) | MS |
| 10 | CPP 22-20 | 23.13 (28.72) | MS |
| 11 | CPP 22-12 | 13.36 (21.39) | MR |
| 12 | CPP 22-2 | 13.63 (21.65) | MR |
| 13 | CPP 22-13 | 14.70 (22.45) | MR |
| 14 | CPP 22-8 | 38.63 (38.41) | S |
| 15 | CPP 22-3 | 27.13 (31.32) | MS |
| 16 | Control | 51.60 (45.90) | |
| S.Em± | 0.97 | ||
| CD (p=0.05) | 2.83 |
Table text extracted from the original PDF; superscript letters are shown inline. The original table image is below.
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| Category | Per cent disease incidence |
|---|---|
| Immune | 0 % |
| Resistant | 0.1-10% |
| Moderately resistant | 10.1-20% |
| Moderately susceptible | 20.1-30% |
| Susceptible | More than 30% |
Table text extracted from the original PDF; superscript letters are shown inline. The original table image is below.
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| Reaction | Per cent disease incidence | No. of varieties/ genotypes | varieties/ genotypes |
|---|---|---|---|
| Resistant | 0.1-10 | 0 | - |
| Moderately Resistant | 10.1-20 | 6 | CPP 22-5, CPP 22-11, CPP 22-15, CPP 22-12, CPP 22-2, CPP 22-13 |
| Moderately susceptible | 20.1-30 | 5 | , CPP 22-10, CPP 23-4, CPP 22-21, CPP 22-20, CPP 22-3 |
| Susceptible | More than 30 | 4 | CSP 23-10, CPP 22-18, CPP 22-9, CPP 22-8 |
Table text extracted from the original PDF; superscript letters are shown inline. The original table image is below.
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References
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- Wheeler BEJ. An Introduction to Plant Disease. London: John Wiley & Sons; 1969. 374 p.