Drought Tolerance Ranking of Soybean Genotypes Obtained with an Automatic Phenotyping Platform Corresponds with Those Obtained in Greenhouse and Field Experiments.

Drought is one of the most important abiotic factors limiting soybean [Glycine max (L.) Merr.] crop productivity worldwide. In order to evaluate the drought tolerance of several genotypes, greenhouse experiment and field trials were carried out in multiple locations in North-West Argentina. Genotypes that yielded more under drought conditions in all environments were identified. The aims of this study were: i) to evaluate a group of soybean genotypes under well watered (WW) and water stress (WS) conditions using GlyPh, a low-cost automatic phenotyping platform, and ii) to compare these results with the previously mentioned experiments. A pot experiment was conducted in an environment-controlled greenhouse using an automatic platform, which allowed the evaluation of genotypes under precisely controlled water stress conditions. Seven commercial genotypes were selected based on previous studies, three of which were included in all experiments. We investigated the effects of moderate drought stress on biomass production and other growth parameters during the vegetative period. Drought susceptibility index (DSI) was calculated and compared with those from previous experiments. Using GlyPh, we were able to detect differences in shoot dry biomass and total leaf area among genotypes under WW and WS conditions (p<0.05). Moreover, the genotypic ranking of drought tolerance based on biomass accumulation during vegetative period agreed with the ranking based on yield in previous experiments. These results indicate that this low-cost automatic phenotyping platform can be useful to detect drought tolerant genotypes, as well as to obtain phenotypic data to map genes associated with drought tolerance.