Interactions of viruses in Cowpea: effects on growth and yield parameters

Kt Kareem,Ma Taiwo

doi:10.1186/1743-422x-4-15

Kt Kareem, Ma Taiwo

Open Access

https://doi.org/10.1186/1743-422x-4-15

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Abstract

The study was carried out to investigate the effects of inoculating three cowpea cultivars: "OLO II", "OLOYIN" and IT86D-719 with three unrelated viruses: Cowpea aphid-borne mosaic virus (CABMV), genus Potyvirus, Cowpea mottle virus (CMeV), genus Carmovirus and Southern bean mosaic virus (SBMV), genus Sobemovirus singly and in mixture on growth and yield of cultivars at 10 and 30 days after planting (DAP). Generally, the growth and yield of the buffer inoculated control plants were significantly higher than those of the virus inoculated plants. Inoculation of plants at an early age of 10 DAP resulted in more severe effect than inoculations at a later stage of 30 DAP. The average values of plant height and number of leaves produced by plants inoculated 30 DAP were higher than those produced by plants inoculated 10 DAP. Most of the plants inoculated 10 DAP died and did not produce seeds. However, " OLOYIN" cultivar was most tolerant and produced reasonable yields when infected 30 DAP. The effect of single viruses on growth and yield of cultivars showed that CABMV caused more severe effects in IT86D-719, SBMV had the greatest effect on "OLO II" while CMeV induced the greatest effect on "OLOYIN". Yield was greatly reduced in double infections involving CABMV in combination with either CMeV or SBMV in "OLOYIN" and "OLO II", however, there was complete loss in yield of IT86D-719. Triple infection led to complete yield loss in all the three cultivars.

Highlights

Cowpea is an annual tropical grain legume, which plays an important role in the nutrition of people in developing countries of the tropics and subtropics, especially in subSaharan Africa, Asia Central and South America
Inoculation of the "OLO II" with a mixture of the three viruses resulted in the greatest reduction in plant height with the average values at 12.7 cm and 22.1 cm for plants inoculated at 10 and 30 days after planting (DAP) compared with the 69.3 cm for the buffer inoculated plants
The results of this study indicate that the three cowpea cultivars used in this investigation were susceptible to the three viruses and the viruses replicate in them in both single and mixed infections

Summary

Introduction

Cowpea is an annual tropical grain legume, which plays an important role in the nutrition of people in developing countries of the tropics and subtropics, especially in subSaharan Africa, Asia Central and South America. Due to its high protein content (20 – 25%), cowpea has been referred to as "poor man's meat". It is very palatable, highly nutritious and relatively free of metabolites or other toxins [1,2]. Host- plant resistance is currently the most effective method for the control of cowpea virus diseases in Africa. An adequate knowledge of the viruses and the strains occurring in the main cowpea-growing areas of Africa is a pre-requisite for effective control [6]

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