Growth and Yield Assessment of Selected Cowpea (Vigna unguiculata L.) Genotypes to Elevated Iron Levels in a Ferruginous Ultisol
- Post by: sulegumes
- April 10, 2019
- Comments off
Background and Objective: The screening of iron-tolerant cultivar is imperative to sustain and improve overall cowpea production. This study investigated the growth and yield responses of selected cowpea ( Vigna unguiculata ) accession to iron toxicity in a ferruginous ultisol. Materials and Methods: Top soil (a ferruginous ultisol) was obtained from an undisturbed garden and sun-dried to constant weight. The soils were divided into 2 groups. One group was the selected ferruginous garden ultisol, whereas the iron level in the other group was elevated by twice the ecological screening benchmark of iron in agricultural soils (400 mg kgG1). One week later, 15 accessions of cowpea, Vigna unguiculata (TVu-3742, TVu-3769, TVu-5348, TVu-5760, TVu-5768, TVu-5782, TVu-5883, TVu-6102, TVu-6193, TVu-6219, TVu-6290, TVu-10600, TVu-10881, TVu-11114 and TVu-11214) were sown in both iron-amended and control soils. Results: Twenty weeks later, results showed differential responses in carotenoids, lycopenes, NAR and DWP across accessions exposed to elevated iron levels. There was general growth suppression accessions planted in Fe-elevated soils (p<0.05) with TVu-3742, 3769 and 6290 were the worst hit while elevated Fe-enhanced rooting parameters in TVu-3769 and 6219 were observed. Per plant yield in TVu-5760, 5768, 6102, 10600, 11114 and 11214 were significantly reduced by over 35%. However, no significant yield changes were reported for TVu-3742, 5768, 5782, 5883, 6193, 6219, 6290 and 10881 under elevated soil iron condition. Conclusion: Given the fact that the control soil was ferruginous, with iron levels higher than 1 g kgG1, the reported capacities for selected accessions to maintain yield levels under further elevated iron conditions suggest possible iron tolerance for those tolerant accessions.
Key words: Antioxidant, ferruginous, growth responses, iron, ultisol, Vigna unguiculata