Selection of wheat genotypes for water deficit tolerance using different drought tolerance indices

The identification of genotypes with high yield and yield stability under drought is the first step towards the generation of novel lines with better adaptation to climate change variation. The aim of this work was to explore the efficiency of ten different drought tolerance indices to identify superior genotypes. Ten wheat genotypes were evaluated for two years under two irrigation regimes: control and water deficit. As expected, the water deficit reduced the phenotypic values, of the evaluated traits in tested wheat cultivars. Significant positive correlations were found considering the grain-yield under both regimes (Yp, Ys), and three drought tolerance indices (DTIs): the Mean Productivity Index (MP), the Stress Tolerance Index (STI) and the Geometric Mean Productivity (GMP). These correlations were confirmed in Bi-plot analysis and the graphical separation of tested genotypes associated with different performances in drought indices. MP, STI and GMP indices consistently selected BioInta 2002, Baguette 9 and BioInta 2004 as the drought tolerant materials, and conversely, Baguette P. 11, BioInta 1005 and Pampeano as drought susceptible materials. These analyses positionate MP, STI and GMP as appropriate tools to find genotypes with contrasting drought response to drought to later be incorporated as genetic resources into breeding programs.