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Screening Cotton Genotypes for Reniform Nematode Resistance
Published on: May 2, 2019
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Broad-based root-knot nematode resistance identified in cowpea gene-pool two
Arsenio D Ndeve1, William C Matthews1, Jansen R P Santos2
1Department of Nematology, University of California , Riverside, CA 92521 , USA.
Journal of Nematology
|May 17, 2019
Summary
New cowpea genotypes resistant to root-knot nematodes (RKN) have been identified, offering improved crop protection against aggressive nematode isolates. These findings provide valuable traits for breeders to enhance cowpea production in RKN-infested fields.
Area of Science:
- Plant Pathology
- Agronomy
- Genetics
Background:
- Cowpea (Vigna unguiculata L. Walp) is a vital protein source for food security in developing regions.
- Root-knot nematodes (RKN) significantly reduce cowpea yields, threatening crop production.
- Existing monogenic resistance (gene Rk) is threatened by increasingly aggressive RKN isolates.
Purpose of the Study:
- To screen cowpea germplasm for resistance to RKN.
- To determine the spectrum of resistance and relative virulence of RKN isolates.
- To investigate the relationship between root-galling and egg-mass production.
Main Methods:
- Screening of 48 cowpea genotypes from Eastern and Southern Africa under field, greenhouse, and controlled conditions.
- Evaluation of resistance to Meloidogyne javanica (Mj) and Meloidogyne incognita (Mi) isolates (avirulent Avr-Mi and virulent Mi).
- Analysis of variance for root-galling (RG) and egg-mass production (EM) data.
Main Results:
- Seven genotypes exhibited broad-based resistance to Mj, Avr-Mi, and Mi isolates.
- Two genotypes showed specific resistance to both Mi isolates.
- Mj and Mi isolates were significantly more virulent than Avr-Mi; new resistant genotypes outperformed the Rk-based resistance.
Conclusions:
- New sources of broad-based and specific RKN resistance were identified in cowpea gene pool two.
- Resistance to RG and EM is controlled by the same genetic factors.
- These findings offer valuable genetic resources for breeding improved, RKN-resistant cowpea varieties.
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