New Sources of Resistance in Cowpea to the Cowpea Aphid (Aphis Craccivora Koch) (Homoptera: Aphididae)

Abstract

Twenty-two advanced breeding genotypes of cowpea were evaluated for their responses to infestation by the cowpea aphid, Aphis craccivora Koch. The aim of the study was to identify genotype(s) of cowpea resistant to A. craccivora to be used as breeding line(s). Seedling screening technique and aphid growth and reproduction on each genotype were used to classify the genotypes into resistant and susceptible groups. The cowpea genotypes SARC 1-57-2 and SARC 1-91-1 were found to be the most resistant genotypes, whereas five of the genotypes namely, Apagbaala, IT 97K-499-35, IT 98K-506-1, IT 95K-193-2 and Marfo-Tuya were highly susceptible. The high susceptibility of the IITA lines must be a cause for concern, particularly the IT 97K-499-35 line which is known to be resistant to A. craccivora in Nigeria. This suggests the existence of cowpea aphid biotype in northern Ghana which is more virulent than the biotypes in Nigeria. The results support earlier findings of the development of aphid biotypes that are more aggressive and are not controlled by the aphid resistance varieties of cowpea developed by IITA for Nigeria. pests and diseases (Montimore et al., 1997; Blade et al., 1997). Cowpea is one crop which suffers serious insect pests infestation from the time of planting through harvesting and during storage (Obeng-Ofori, 2007). Cowpea aphid, Aphis craccivora Koch (Homoptera: Aphididae) is a major insect pest of cowpea in Africa, Asia and the Americas (Obeng-Ofori, 2007). Singh and Allen (1980) estimated yield losses of 20% to 40% in cowpea due to A. craccivora infestation in Asia and up to 35% in Africa. The existence of alternative host plants during the crop-free season, intermittent dry periods during the rainy season and favourable tem

Screening of cowpea (Vigna unguiculata (L.) Walp.) lines for resistance to three Aphids (Aphis craccivora Koch) strains in Burkina Faso

“…These results are consistent with those of Kusi et al (2010) who identified SARC-1-57-2 and SARC1-91-1 as resistant to aphids. IT97K-556-6 is the most resistant line to all the three strains of aphids with an average survival rate equal to 93.33% and a degree of infestation equal to 1.4.…”

“…Moreover, in this study the confinement of aphids increased the parasitic pressure on plants. This pressure would have been able to induce an excessive compensatory response (Kusi, 2010) in KN1 physiological response, which was manifested by a much greater production of leaves. This compensatory response, combined with the antibiosis activity developed by the line, gave it an unexpected resistance to aphids.…”

“…Host plant resistance is an efficient and environmentally friendly way of controlling insects, including aphids. Some cowpea lines have been screened in Africa and different levels of resistance to aphids have been found (Kusi et al, 2010;Souleymane et al, 2013;Aliyu andIshiyaku, 2013, Omoigui et al, 2017). Unfortunately resistance-breaking biotypes have occurred in several plant-aphid systems (Dogimont et al, 2010).…”

A novel aphid resistance locus in cowpea identified by combining SSR and SNP markers

“…SARC 1‐57‐2 was observed to be resistant to A. craccivora under both screen‐house and field conditions among a large number of test lines (Kusi et al., ). One hundred and sixty‐nine (169) F 2 lines of the cross between ‘Apagbaala’ and SARC 1‐57‐2 were tested for their reaction to aphid infestation in a screen‐house facility using standard protocols (Bata et al., ; Kusi et al., ). As soon as individual lines could be unambiguously classified into resistant or susceptible classes, they were sprayed with lambda cyhalothrin (Lambda Super ® ) to control the aphids.…”

“…Ongoing research at the CSIR‐Savanna Agricultural Research Institute (CSIR‐SARI) to identify additional sources of aphid resistance in cowpea revealed a number of advanced breeding lines, including SARC 1‐57‐2, with high levels of resistance (Kusi et al., ). In these tests, lines with the IT84S‐2246 source of resistance were not more resistant than the susceptible check, ‘Apagbaala’.…”