Screening of Abelmoschus esculentus and Abelmoschus callei cultivars for resistance against okra leaf curl and okra mosaic viral diseases, under field conditions in South Eastern Nigeria

Abstract

Of all the several factors that limit okra production in West Africa, okra mosaic virus disease (OMVD) and okra leaf curl disease (OLCD) are rank among the most severe. Twenty three (23) Abelmoschus esculentus and Abelmoschus callei cultivars retrieved from the local farmers were screened in the open field for the resistance against OMVD and OLCD over two cropping seasons in Nsukka, South Eastern Nigeria. The degree of susceptibility was determined by the calculation of yield decline (YD) due to changes in the fruit yield with exposure to the disease causing agents as well as virtual scoring of the exposed plants. The results show that all the A. esculentus cultivars were susceptible to the two diseases. The findings indicate that contrary to general belief, not all A. callei cultivars are resistant to these viral diseases. Any cultivar with a YD score of less than 10% was identified as a potential candidate for the disease resistant genes. Only Ebi Ogwu, Ojo ogwu, Tongolo, VLO, Oru ufie and Ogolo met this criterion. The potentials of transferring these resistant genes from A. callei cultivars to the vulnerable A. esculentus cultivars are discussed.

Keywords: Okra, screening, resistance, viral diseases.

African Journal of Biotechnology, Vol 13(48) 4419-4429