Success Eni Kalu^1,2, Godwin Michael Ubi^1*,  Aniefiok Ndubuisi Osuagwu¹, Imoh Akpanobong Ekpo¹,Linus Uduak Edem¹

¹Department of Genetics and Biotechnology, University of Calabar, Calabar, Nigeria

²Department of Biological Sciences, Clifford University, Owerrinta, Nigeria

Abstract

Air potato yam (Dioscorea bulbifera L.) is an indigenous, edible, and energy-giving crop and used as herbal remedy for common ailments like diabetes, dysentery and conjunctivitis. This study sought to determine the tolerance of D. bulbifera to salt stress conditions through molecular, biochemical and physiological approaches. Results revealed that most of the local lines were less tolerant to sodium chloride showing reduced concentrations of chlorophyll a and b of the plants, and also showed increased activities of peroxidase, linolytic, xylanase, cellulase and glucose-6- phosphate dehydrogenase enzymes at increasing salt concentration and stress. Molecular analysis using Simple Sequence Repeats (SSR) revealed that 11 lines did not contain any trait related to the marker. Twenty eight (28) lines fingerprinted at 100 bp with the marker gene. Nine lines were fingerprinted at 300 bp with the marker gene while Dbor 1 fingerprinted at 100, 200, 300 and 400 bp with the marker gene. Three of the local lines which are round in shape, Dbor 1, Dbok 3 and Dbak 2 produced several bulbils at 300Nm of salt concentration and showed molecular bands at 400 and 300 bps indicating the presence of a salt tolerant gene at the locus and base pairs. Therefore, molecular analysis has revealed the presence of salt tolerant gene at 300 400 bp in the three local lines which can be further harnessed for salt-tolerance improvement in the less tolerant lines. Physiologically, chlorophyll contents and enzyme concentrations in the less tolerant local lines were critically affected with increasing salt concentrations.

 Keywords: Enzymes assay, SSR markers, Chlorophyll a & b, Aerial yam, Salt tolerant lines