Influence of Salinity on the Growth and Yield of two Varieties of Okra (Abelmoschus esculentus (L.) Moench) in Abeokuta, Ogun State, Nigeria

Abstract

Soil salinity is one of the most severe abiotic factors limiting vegetable crop production. The present study aimed to evaluate the effect of salinity on growth, biomass and yield of two okra (Abelmoschus esculentus (L.)) varieties: Clemson Spineless and LD88 (Moench) varieties grown under screen-house in Abeokuta, Ogun State, Nigeria. The seeds were obtained from National Horticultural Research Institute (NIHORT), Ibadan, Nigeria and cultivated in 4.5 litre plastic pots in sandy-loam soil (pH 6.7) under completely randomised design (CRD) with three replications in the Department of Botany screen house, Federal University of Agriculture, Abeokuta. The salinity regim of Sodium Chloride (NaCl) imposed were 0% NaCl (control), 0.05%, 0.10% and 0.15% NaCl solution, at 3-day intervals. Growth measurements such as plant height, number of leaves, leaf area, shoot and root dry weight, pod number, pod length, pod dry weight, relative growth rate (RGR), net assimilation rate (NAR) and leaf area ratio (LAR) were taken every week.  All growth and yield parameters were significantly (P<0.05) inhibited with salinity in both varieties when compare with the control. The RGR of Clemson Spineless decreased from 0.46 to 0.14 g g⁻¹ month⁻¹ at 0.15% NaCl. RGR of LD88 decreased from 0.46 to 0.14 g g⁻¹ month⁻¹ at the highest salinity level. The optimal concentration of NaCl that has the inhibitoriest effect on all parameters is 0.15%. Throughout the studies Clemson Spineless was consistently outperformed by LD88. A. esculentus is very salt sensitive, while the salt tolerant LD88 is recommended for growing in saline areas