Otie Victoria^1,2, Udo Idorenyin³, Matsuura Asana⁴, Liu Jia², Liang Shuoshuo², Shao Yang⁵, Itam Michael Okoi⁶, An Ping^2*, Eneji Anthony Egrinya¹

1Department of Soil Science, Faculty of Agriculture, Forestry and Wildlife Resources Management, University of Calabar, P.M.B. 1115, Calabar, Nigeria

2Arid Land Research Centre, Tottori University, Hamasaka 680-0001, Tottori, Japan

3Department of Crop Science, Faculty of Agriculture, Forestry and Wildlife Resources Management, University of Calabar, P.M.B. 1115, Calabar, Nigeria

4Faculty of Agriculture, Shinshu University, 8304, Kamiina County, Nagano 399-4598, Japan

5College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China

6Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing 48824, MI, USA

Abstract

Salt stress is a key ecological challenge to wheat establishment at the early stage of germination, especially in drylands. A germination experiment was conducted to determine whether an exogenous seed treatment with 24-epibrassinolide could mitigate salinity stress effects on wheat germination. Seeds of the Sudanese wheat cv. Imam were treated with 24-epibrassinolide (BR1) or without (BR0) at eleven concentrations of sodium chloride (NaCl) (0.00, 1.56, 3.13, 4.69, 6.25, 7.81, 9.38, 10.94, 12.50, 14.06 and 15.63 dSm-1), in a 2 x 11 factorial experiment arranged into a completely randomized design. Seed germination was progressively delayed with increasing salinity and the daily germination was reduced significantly. The germination average time and relative injury rate increased considerably (p≤0.05) at salt levels of 7.81 dSm-1or more. The inhibitory effects of salinity on germination were significantly (p≤0.05) reversed by seed treatment with BR1. Wheat cv. Imam tolerated salt stress up to 6.25 dSm-1 at BR0 with respect to velocity of germination, germination rate, final germination rate, germination percentage and germination index, relative to no salt (0.00 dSm-1). An early uniform establishment of wheat in saline media could be enhanced by seed treatment with BR.

Keywords: Arid region, Plant growth hormone, Triticum aestivum (L), Abiotic stress