Growth and yield components of some groundnut (Arachis hypogaea L.) cultivars infected with blackeye cowpea mosaic virus
Blackeye cowpea mosaic virus (BlCMV) is a major virus, infecting legumes with attendant huge losses. Cultivation of resistant varieties is the most effective and sustainable control strategy. Therefore, some groundnut (Arachis hypogaea) cultivars were evaluated against BlCMV in Minna, Southern Guinea savanna zone of Nigeria. The experiment was conducted at the Teaching and Research Farm, Federal University of Technology, Minna. It was arranged as infected and uninfected using Randomised Complete Block Design (RCBD) with three replications. Groundnut seeds were sowed in the second week of August, 2015. Seedlings were inoculated by sap transmission at 10 days after sowing. Disease incidence, severity, growth and yield attributes were recorded. Data were subjected to analysis of variance (ANOVA) and means separated at p≤0.05 probability level. Disease incidence varied significantly p<0.05 from 28.3 to 60.3 % at one week after inoculation (WAI) and 44.7 to 100 % at 2 WAI. ICGV 91317 which expressed mild infection (symptom score = 2) at 9 WAI also exhibited the lowest leaf diameter reduction (3.6 %) at that growth stage. FDRF7-82 which had the lowest reduction in number of leaves per plant at 3 and 6WAI (10.7 and 9.6 %, respectively) also exhibited the lowest reduction in fresh haulm weight per plant (42.2 %). None of the cultivars exhibited consistent reactions, FDRF7-82 and ICGV 91317 had an appreciable combination of growth and yield attributes under BlCMV infection. However, these cultivars could be improved upon either through conventional or molecular breeding by coding with desirable genes. The cultivars which were adversely affected by BlCMV disease could so be improved genetically through appropriate gene introgression from the resistant cultivars.
Keywords: Blackeye cowpea mosaic virus; disease incidence and severity; growth and yield; groundnut