Selection of Oily Sunflower (Helianthus annuus L.) Drought Tolerant Lines using Tolerance Indices

In order to evaluate the genetic diversity of oily sunflower lines, screening drought tolerance indices and identification of drought tolerant lines, 100 oily sunflower lines were evaluated in a simple lattice design under both well-watered and water-limited stressed conditions in 2016. Based on the potential (Yp) and stress (Ys) yield, quantitative drought tolerance criteria such as: mean productivity (MP), tolerance index (TOL), geometric mean productivity (GMP), harmonic mean (HM), stress susceptibility index (SSI) and stress tolerance index (STI) were calculated. Generally, the line with code number of 8 with average yield of 81.25 gr/plant and line 66 with average yield of 5.43 gr/plant showed maximum and minimum seed yield, respectively. Correlation analysis between drought tolerance indices with well-watered and water-limited stress yields revealed that indices such as MP, GMP, HM and STI are the most suitable criteria for screening sunflower lines. In well-watered and water-limited stressed conditions, the highest value of MP, GMP, STI and HM were observed in line 8. Regarding these four criteria and high values of Yp and Ys, line 8 was chosen as the best line for using as a parental line in hybrid varieties production and development of segregating populations.