Physiological changes associated with Okra mosaic virus infection in field grown okra plants

As a prerequisite for the breeding of virus-resistant okra cultivars, the effect of Okra mosaic virus infection on physiological performance of ten okra cultivars were assessed under field conditions within the coastal savannah agro-ecological zone of Ghana. All cultivars succumbed to the disease and expressed varying degrees of symptoms. The results showed that plant height at initial and 50% flowering were significantly reduced with cultivar Clemson spineless showing the highest reduction of 38% and 35% respectively. Plant height at 50% podding was also reduced in all cultivars with the highest reduction (40%) occurring in cultivar Clemson spineless. Virus-infected plants of cultivars Kwabenya 1, Labadi dwarf and Asutem took on the average 43 days to attain 50% flowering compared to 25 days in healthy or control plants. Diseased plants had significantly (P<0.05) delayed, taking on the average 47 days after planting to attain 50% podding compared to the control plants with an average of 35 days. Infected plants of cultivars Kwabenya 1 and Labadi dwarf took the highest number of 51 days to attain 50% podding. Pod length and width were also reduced in all cultivars but were highest in cultivars Lucky 19 F1 and Clemson spineless at 52.19% and 46.25% respectively. Based on this assessment, cultivars Adom and Asutem which were less affected in terms of disease severity and fruit yield reduction could be exploited in future breeding programmes.