GENETIC VARIATION FOR RESISTANCE TO YELLOW VEIN MOSAIC VIRUS AND NUCLEIC ACID HYBRIDIZATION TEST IN KENAF (HIBISCUS CANNABINUS L.)
Keywords:Begomoviruses, diversity, fiber crop, incidence, Malvaceae
Kenaf is an important economic crop cultivated for the production of bast fibers which are used for industrial purposes. In spite of the uses of kenaf, its production is hindered by biotic stresses including viruses of which yellow vein mosaic virus (YVMV) is the most devastating. The effect of genotype and location on the incidence and severity of yellow vein mosaic disease (YVMD) in kenaf was determined and the presence of the virus in kenaf genotypes was detected with nucleic acid spot hybridization (NASH) test. Fifteen genotypes of kenaf were screened for tolerance to YVMV in three agro-ecological zones (Ibadan, Ikenne and Ilora) in Nigeria under rain-fed conditions in 2015 and 2016. Plot size of 2 m × 2 m with a spacing of 0.2 m x 0.5 m was used and the experiment was laid down in a randomized complete block design (RCBD) with three replicates. The NASH test revealed the presence of YVMV in kenaf plants. Significant (p < 0.01) variation among the genotype for low incidence and severity to YVMD was indicated. The environments affected the genotypes and influenced differential response of kenaf to YVMD across the locations. Ibadan (forest-savanna) was indicated as the most discriminating and representative environment to develop YVMD-resistant genotype for the ecology. Low incidence of YVMV was observed for HIB14, HIB23, Ex-shika 242, Tianung1, Tianung2, V1-100, V1-400 and IfekenD1-400 at Ibadan and Ikenne; AU-71 at Ilora2016 and HIB43, HIB31, HIB24 at Ilora2015. Genetic similarity was indicated for Ex-shika242, AU-71 and V1-400. Tianung1, Ex-Shika242 and V1-400 were recommended for release as resistant genotypes for the ecologies.