Mitigating Impact of Soil Salinization on Growth, Yield and Fruit Nutritional Quality of Abelmoschus esculentus L. (Okra) Using Arbuscular Mycorrhiza Fungus (Glomus clarum)

Soil salinity is a severe environmental stress that limits crop growth and productivity. Mycorrhizal fungi association has the potential to minimize environmental stress like soil salinization in some plant species. Hence, an experiment was conducted to examine the potential of an Arbuscular mycorrhiza (AM), Glomus clarum, to reduce salt stress in Abelmoschus esculentus L. (okra). Seedlings of A. esculentus were raised in perforated plastic pots filled with 3 kg top soil; treated with 0 (control), 35, 70, 140, 280 or 560 mM NaCl solution; and grouped into two. Each pot in the first group was inoculated with 20 g of AM spawn while pots in the second group were not inoculated with the mycorrhizal fungus. The experiment was laid out in a completely randomized design with each treatment replicated 5 times. Growth parameters in plants without AM including plant height, stem girth, leaf area and number of leaves decreased significantly with increasing salt concentration compared to the control. Salinity also reduced the growth parameters in plants with AM but did not differ significantly from the control. Fresh and dry weight of plant parts, total biomass, number of fruits, fruit fresh and dry weights as well as leaf total chlorophyll were reduced by salinity, but significant differences were recorded only in plants without inoculation with AM. Salinity with or without AM did not significantly affect fruit nutritional and proximate composition of A. esculentusn except Na^+ that increased with increasing soil salinity. Inoculation of saline sites with arbuscular mycorrhizal fungus, Glomus clarum, could serve as a sustainable and environmentally safe treatment to enhance salinity tolerance in okra for improved productivity.