Assessment of Sunflower (Helianthus annuus L.) Genotypes for Salinity Tolerance during Germination: A Physiological Traits Analysis

Abstract

Sunflower (Helianthus annuus L.) is considered a moderately salt-tolerant crop; however, salinity stress remains a major limiting factor affecting germination, growth, and yield. The crop’s ability to perform under saline conditions varies with genotype, growth stage, and environmental influences. Among these, seed germination is one of the most sensitive and critical stages, as successful germination ensures uniform seedling establishment and overall crop performance. The present study aimed to assess of Sunflower genotypes for Salinity Tolerance during Germination. The study was conducted at the College of Agriculture, Raichur, Karnataka, to examine the physiological response of sunflower genotypes to salt stress during germination. A Factorial Completely Randomized Design (FCRD) was adopted, involving twenty-two sunflower genotypes and five NaCl concentrations (0, 100, 200, 300 and 400 mM). Seed physiological parameters such as germination rate (GR), germination index (GI), germination vigor index (GVI), water content (WC) and seedling vigor index-II (SVI-II) were evaluated to assess the impact of salinity. The results indicated considerable variation among genotypes in their response to salt stress, with certain genotypes maintaining better germination and physiological traits even under higher NaCl concentrations. Enhanced water uptake or retention may explain CMS-38B’s resilience. RCR-9 exhibited a sharp decline in water content from 77.41 % in the control to 55.96 % at 200 mM NaCl, indicating low salinity tolerance. This suggests difficulty in maintaining hydration under osmotic stress. Such susceptibility may restrict its growth and seed development in saline conditions. The findings enhance our understanding of genotypic variability in response to salinity during the early growth stage of sunflower.