EFFECTIVE SELECTION CRITERIA FOR SCREENING DROUGHT TOLERANT RECOMBINANT INBRED LINES OF SUNFLOWER

In this study, seventy two sunflower recombinant inbred lines were tested for their yielding ability under both water-stressed and well-watered states. The inbred lines were evaluated in a rectangular 8x9 lattice design with two replications in both well-watered and water-stressed conditions, separately. Eight drought tolerance indices including stability tolerance index (STI), mean productivity (MP), geometric mean productivity (GMP), harmonic mean (HM), stress susceptibility index (SSI), tolerance index (TOL), yield index (YI) and yield stability index (YSI) were calculated based on grain yield for every genotype. Results showed the highest values of mean productivity (MP) index, geometric mean productivity (GMP), yield index (YI), harmonic mean (HM) and stress tolerance index (STI) indices for 'C134a' inbred line and least values of stress susceptibility index (SSI) and tolerance (TOL) for 'C61' inbred line. According to correlation of indices with yield performance under both drought stress and non-stress states and principle component analysis, indices including HM, MP, GMP and STI could properly distinguish drought tolerant sunflower inbred lines with high yield performance under both states. Cluster analysis of inbred lines using Y-s, Y-p and eight indices, categorized them into four groups including 19, 6, 26 and 19 inbred lines.