[en] In this study, 21 genotypes of sunflower (&nbsp;Helianthus annuus L.) derived from a half diallel cross between six inbred lines were evaluated in both water-stressed and well-watered environments. In each environment, the genotypes were evaluated using a randomized complete block design with three replications. From the grain yield data, drought tolerance indices comprising of 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 for every genotype. The resulting data were analyzed as obtained from a randomized complete block design. Significant differences among genotypes were observed for all drought tolerance indices except for SSI and YSI. High yield value in non-stress and stress environments was exhibited by genotypes &lsquo;LR4 &times; LR25&rsquo; (14.02 g) and &lsquo;LR25 &times; C100&rsquo; (3.84 g) respectively. The maximum value of STI (0.93), MP (8.72), GMP (6.91) and HM (5.48) indices was by genotype &lsquo;LR4 &times; LR25&rsquo;. Correlation coefficients revealed that TOL, MP, GMP, STI, HM, and YI indices could effectively be used for screening of drought tolerant genotypes. Using MP, GMP, HM, TOL, YI and STI indices, genotypes UPGMA classification was done and three clusters were established that paralleled the biplot analysis results. According to results in this study, &lsquo;LR4 &times; LR25&rsquo; is the most drought tolerant genotype which was clustered as group A. We suggest that tolerance indices including MP, GMP and HM are suitable for sunflower drought tolerant genotypes selection.

[es] En este estudio, 21 genotipos de girasol (&nbsp;Helianthus annuus L.) derivados de un cruce medio dial&eacute;lico entre seis l&iacute;neas puras se evaluaron con y sin estr&eacute;s h&iacute;drico. Para cada ambiente, los genotipos se evaluaron usando un dise&ntilde;o de bloques completos al azar con tres repeticiones. De los datos de rendimiento de grano se calcularon los &iacute;ndices de tolerancia a la sequ&iacute;a para cada genotipo: &iacute;ndice de estabilidad de la tolerancia sexual (ITS), productividad media (MP), productividad media geom&eacute;trica (GMP), media arm&oacute;nica (HM), &iacute;ndice de susceptibilidad al estr&eacute;s (SSI), &iacute;ndice de tolerancia (TOL), &iacute;ndice de rendimiento (YI) e &iacute;ndice de estabilidad del rendimiento (YSI). Los datos resultantes se analizaron como obtenidos a partir de un dise&ntilde;o de bloques completos al azar. Se observaron diferencias significativas entre los genotipos en todos los &iacute;ndices de tolerancia a la sequ&iacute;a a excepci&oacute;n de SSI y YSI. Los genotipos &lsquo;LR4 &times; LR25&rsquo; y &lsquo;LR25 &times; C100&rsquo; exhibieron un alto rendimiento en ambos ambientes (14,02 y 3,84 g, respectivamente); &lsquo;LR4 &times; LR25&rsquo; present&oacute; el valor m&aacute;ximo de los &iacute;ndices STI (0,93), MP (8,72), GMP (6,91) y HM (5,48). Los coeficientes de correlaci&oacute;n revelaron que los &iacute;ndices TOL, MP, GMP, STI, HM y YI podr&iacute;an ser utilizados para la selecci&oacute;n de genotipos tolerantes a la sequ&iacute;a. Utilizando los &iacute;ndices MP, GMP, HM, TOL, YI y STI, se hizo una&nbsp; clasificaci&oacute;n UPGMA de los genotipos y se establecieron tres grupos an&aacute;logos a los resultados del an&aacute;lisis biplot. De acuerdo a los resultados de este estudio, &lsquo;LR4 &times; LR25&rsquo;, del grupo A, es el genotipo m&aacute;s tolerante a la sequ&iacute;a. Se concluye que los &iacute;ndices de tolerancia MP, GMP y HM son adecuados para la selecci&oacute;n de genotipos tolerantes a la sequ&iacute;a en girasol.