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Cowpea differential response to striga gesnerioides
This study evaluated 35 cowpea varieties for resistance to Striga gesnerioides using a pot technique method. Some breeding lines and local accessions showed complete resistance, with zero haustoria formed on roots. Striga emerged as early as 25 days after sowing. Variability existed among the varieties, with the number of Striga per pot ranging from 0 to 2.33. Varieties with some level of resistance were identified and should be tested against different Striga strains to establish their reactions and potential for use in improving resistant in susceptible varieties.
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Cowpea differential response to striga gesnerioides
- 1. Differential Response ofCowpea (Vigna unguiculata (L) Walp), Germplasm to Striga gesnerioides using the Pot Technique Method Buba U. M, Boukar O, Abdul S. D and Yakubu H
- 2. Cowpea isan important grain legume that is widely cultivated in most tropical and sub-tropical countries of the world ,especially Sub-Saharan Africa West and Central Africa account for more than sixty five (65%) percent of total world production. Cowpea has high protein quality due to its high levels of lysine and methionine Cowpea complements starchy staple food crops such as millet, sorghum, maize and cassava
- 3. It canfix nitrogen even in soils where organic matter content is less than 2% and sand proportion is up to 85% (Singh et.al 1997); It is an effective resource in cereal based cropping system (Carsky et.al,2003 ) However, average yield per hactare for Nigeria is as low as 270kg/ha compared to African average Low yield is associated to both biotic and abiotic factors.
- 6. Large variabilityof wild and cultivated types within the cowpea genome Some resistant genotypes among local landraces and wild accessions have been identified Gene(s) for resistance –easily identified (dominant) and incorporated into cultivated varieties
- 7. Only verticalresistance(single dominant gene) has so far being reported ,conferred by three independent genes belonging to two homologues The parasitic plant is self pollinating > any mutation leads to fixation of genes > New strains of parasite evolved> seven distinct races in West Africa have been reported
- 8. The currentexperiment was conducted to evaluate some selected germplasm in order to identify sources for multiple genes which may confer horizontal resistance Examine some characters related to striga e.g day to emergence & number of haustorium on roots indicating level of resistance
- 9. Thirty fivecowpea cvs (breeding lines, local accessions) were tested for their reaction to striga gesnerioides Striga seeds was collected at IITA and conditioned at 17-21 oc in an incubator for 10 days and transferred to experimental pots Cowpea were sown as described by Berner et al 1997 Data collected on host plant and parasite number of haustorium/pot
- 10. Number of emergedstriga seedlings per pot Plant height at different stages, Number of pods per plant, Cowpea seed weight, Day to first flower and Day to 50% flowering in cowpea
- 11. GENOTYPE haustoriumcount Breeding lines IT99K-573-2-1 0.00 IT03K-338 0.00 IT90K-372-1-2 0.00 IT93K-1399 0.00 IT99K-573-1 0.00 IT97K-494-6 0.00 IT97K-499-35 0.00 IT98K-205-8 0.00 IT99K-216-44 0.00 GENOTYPE haustorium coun Local accessions Tvu12848 0.00 Tvu 14676 0.00 Tvu 16514 0.00 Tvu 7778 0.00 Tvu 1272 0.00 Tvu 12470 0.00 Tvu 12431 0.00 Tvu 12431 0.00
- 12. Variety Mean haustoriacount IT93K-693-3 0.67 Dan’ila 0.67 IT00K-1217 0.33 IT00K-1263 0.33 IT84S2246-2 0.33 IT99K-7-21-2 0.67 IT98K-288 1.00 IT98K-506-1 0.66 Tvu 1682 0.64 Tvu 1331 1.00 Tvu 10404 0.67 Tvu11682 1.00
- 13. Day tostriga Mean striga Genotype emergence per pot Aloka 31 1.67 IT84S-2246-4 25 0.66 IT99K-7-21-2-2 50 1.00 Tv u 10404 36 0.67 Tvu 11682 29 1.00 IT98K-288 34 1.00 Tvu 13496 38 1.00 Tvu 13994 34 1.33 Tvu 474 32 2.33 Tvx 3236 32 1.3 Mean 34.1 1.19 Sed ±1.21 ±0.25
- 14. Substantial variabilityexist within the selected germplasm Some cultivars have shown complete resistance they include some that were recently evaluated in Northern Guinea Savanna (Omogui et al 2012) Striga emerged as early as 25 days after sowing cowpea Mean number of striga/pot on Tvu 474 was high –this may be an indicating its high susceptibility
- 15. Cowpea accessionsthat have shown some level of resistance to S gesnerioides need to tested against the different strains of S.gesnerioides so as to establish their reaction these strains and possible usage /incorporation into susceptible varieties
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