Occurrence and distribution of pepper veinal mottle virus and cucumber mosaic virus in pepper in Ibadan, Nigeria

Viral diseases constitute obstacles to pepper production in the world. In Nigeria, pepper plants are primarily affected by pepper veinal mottle virus (PVMV), Cucumber mosaic virus (CMV), Pepper leaf curl Virus (TLCV), Tobacco mosaic virus (TMV), Pepper mottle virus (PMV) and a host of other viruses. The experiment was carried out with a diagnostic survey on the experimental field of the National Horticultural Research Institute, Ibadan, Nigeria and on pepper farms in six local government areas within Ibadan Oyo State, Nigeria, forty samples were collected from each of the farms. Diseased samples were obtained from the field and taken to the laboratory for indexing. In ELISA test some of the samples from the pepper farms showed positive reaction to single infection with PVMV (36.79%), CMV (22.14%) while some others showed positive reaction to mixed infection of the two viruses (10%) but some also negative reaction to PVMV and CMV antisera (31.07)

Genetic mapping and legume synteny of aphid resistance in African cowpea (Vigna unguiculata L. Walp.) grown in California

The cowpea aphid Aphis craccivora Koch (CPA) is a destructive insect pest of cowpea, a staple legume crop in Sub-Saharan Africa and other semiarid warm tropics and subtropics. In California, CPA causes damage on all local cultivars from early vegetative to pod development growth stages. Sources of CPA resistance are available in African cowpea germplasm. However, their utilization in breeding is limited by the lack of information on inheritance, genomic location and marker linkage associations of the resistance determinants. In the research reported here, a recombinant inbred line (RIL) population derived from a cross between a susceptible California blackeye cultivar (CB27) and a resistant African breeding line (IT97K-556-6) was genotyped with 1,536 SNP markers. The RILs and parents were phenotyped for CPA resistance using field-based screenings during two main crop seasons in a ‘hotspot’ location for this pest within the primary growing region of the Central Valley of California. One minor and one major quantitative trait locus (QTL) were consistently mapped on linkage groups 1 and 7, respectively, both with favorable alleles contributed from IT97K-556-6. The major QTL appeared dominant based on a validation test in a related F2 population. SNP markers flanking each QTL were positioned in physical contigs carrying genes involved in plant defense based on synteny with related legumes. These markers could be used to introgress resistance alleles from IT97K-556-6 into susceptible local blackeye varieties by backcrossing. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11032-015-0254-0) contains supplementary material, which is available to authorized users