Selection and validation of marker set for selection of resistant varieties of cowpea to Cowpea Aphid-borne Mosaic Virus (CABMV) in Burkina Faso

Vegetable cowpea is eaten mainly fresh, in the form of young, immature pods, tender and sweet like the common bean. However, like cowpea with seeds, vegetable cowpea experience yield losses due to the cowpea aphid-borne mosaic virus (CABMV). This study aims to improve yields through the development of vegetable cowpea varieties resistant to CABMV. The study focused on ten varieties of vegetable cowpea, carried out in a greenhouse at the Kamboinsé research station using a randomized complete block design with three replications, all inoculated with CABMV. The data collection concerned resistance parameters. Mechanical inoculation made it possible to observe various symptoms of CABMV, thus highlighting the existence of variability within the varieties tested. Strong correlations were observed between several variables. Thus, the varieties of vegetable cowpea IT85F-2089-5, UG-CP-8, IT85F-2805-5 and Telma were identified as resistant, because belonging to the low severity classes and having a low value of area under the disease progress curve. On the other hand, the varieties RW-CP-5, UG-CP-6, IT83S-911, niébé baguette grimpant possessing a high severity class were judged to be susceptible. These resistant varieties will thus be able to contribute to the improvement of production and the protection of cowpea resources in Burkina.

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Cowpea aphid-borne mosaic virus (CABMV) in Passiflora by qPCR analysis reveals asymptomatic plants with viruses and new species with immunity

10.21203/rs.3.rs-234183/v1 ◽

2021 ◽

Author(s):

Zanon Santana Gonçalves ◽

Onildo Nunes de Jesus ◽

Lucas Kennedy Silva Lima ◽

Ronan Xavier Corrêa

Keyword(s):

New Species ◽

Virus Infection ◽

Mosaic Virus ◽

Disease Index ◽

Passion Fruit ◽

Rt Pcr ◽

Qpcr Analysis ◽

Resistant Varieties ◽

Cowpea Aphid ◽

Temporal Progress

Abstract The passion fruit woodiness disease (Cowpea aphid-borne mosaic virus – CABMV) causes socioeconomic problems for Brazilian passion fruit crop. Understanding the temporal progress of the disease and identifying resistance sources to CABMV are essential steps to develop resistant varieties. The objective of the study was to evaluate temporal progress of passion fruit woodiness disease, identify Passiflora genotypes with CABMV resistance and to detect virus infection in asymptomatic plants by qPCR. The experiment was conducted in a greenhouse using 128 genotypes belonging to 12 species and three hybrids (inter and intraspecific) of Passiflora evaluated in five periods after inoculation. The symptoms severity was quantified from the disease index (DI%). The CABMV infection in symptomatic plants was confirmed by RT-PCR and in asymptomatic plants by qPCR. Progress rates and disease severity were lower in the species P. cincinnata, P. gibertii, P. miersii e P. mucronata compared to P. edulis, P. alata, Passiflora sp. and hybrids. Of the evaluated genotypes, 20.31% were resistant, with emphasis on the accessions of P. suberosa, P. malacophylla, P. setacea, P. pohlii e P. bahiensis that did not show symptoms of virus. The absence of symptoms does not imply immunity of plants to the virus, as the qPCR analysis confirmed infection by the virus in asymptomatic plants of P. cincinnata, P. gibertii, P. miersii, P. mucronata, P. setacea, P. malacophylla e P. suberosa. Even after four inoculations, the virus was not detected by qPCR in the upper leaves in plants of P. pohlii and P. bahiensis indicating that these species are immune to CABMV.

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