Document Type: Research Paper
Department of Crop Production and Plant Breeding, College of Agriculture, Shiraz University, Shiraz Iran
Department of Water Engineering, College of Agriculture, Shiraz University, Shiraz, Iran.
Despite general effect of salicylic-acid (SA) in improving plant growth and
productivity in saline conditions, there have not been unanimity about the best
concentration. In this 2-yr field study the effect of different SA concentrations
(0, 0.5, 1.0, 1.5 and 2.0 mM) was examined on growth, grain yield and yield
components of barley under two non-saline (2 dS m-1) and saline (12 dS m-1)
conditions. By using response curves and regression analyses the best concentration
was also determined. The results showed that salt stress decreased barley plant
height (22.7%), fertile tillers (19.0%), ear length (21.6%), grain number per ear
(22.5%), thousand grain weight (19.9%), biological yield (29.6%) and grain yield
(37.6%). Since salinity treatment when imposed the tillers were at their rapid
growth phase; therefore, fertile tiller number per unit area was found to be the most
sensitive trait to salt stress. Nonetheless, SA foliar application in different
concentrations could ameliorate some of these negative impacts on growth, yield
and yield components. Reduction percentage of grain yield due to salinity was
the lowest at 1.5 mM in first and 1.0 mM SA concentration in second year
corresponding to 27.3% and 33.8%, respectively; while those were highest at no-SA
treatments (42.2% and 43.8% in first and second year, respectively). Modulating role
of SA for adverse effect of salinity could be attributed to enhanced grain number.
Based on the result of regression analysis, it can be concluded that SA foliar
application at 2.0 mM under non-saline and at 1.41 mM under saline conditions
could be considered as the best concentrations for improving barley performance.