EXOGENOUS APPLICATION OF SALICYLIC ACID AMELIORATES GROWTH AND YIELD OF SUNFLOWER (Helianthus annuus L.) IN SALINE SOIL

Abstract

Salicylic acid (SA) is an endogenic plant hormone, acting as an antioxidant with various impacts on plant tolerance to biotic and abiotic stresses. The main objective of this study was to investigate the influence of SA on growth and yield of sunflower under saline condition. Our study was undertaken at the Agronomic Research Area of Bahauddin Zakariya University Multan, in soil filled pots during Spring 2016. The soil applied was moderately saline in nature (14.5 d Sm-1 ). The experimental design was completely randomized design with a 2´4 factorial arrangement of treatments: two sunflower hybrids (S-278 and Hysun-33) and four SA concentrations (control 0 mM SA, 10, 55 and 100 mM SA, as foliar application). Growth of sunflower in control was adversely affected under saline soil. However, the effect of salt stress was alleviated by foliar spray of SA, which ameliorated the growth and yield variables of both sunflower hybrids. Foliar application of 10 mM SA enhanced plant height, stem diameter and chlorophyll contents under saline condition, whereas 10 mM SA positively influenced head diameter, achene yield and oil contents, as compared to the other treatments. Hybrids S-278 performed significantly better than Hysun-33 regarding plant height and oil contents. Foliar application of 10 mM SA was the best for sunflower under moderately saline soils.