In the face of increasing climate variability, a team of INTA scientists is exploring strategies to optimize soybean production — one of Argentina’s most vital crops. The initiative, led by the Plant Ecophysiology Group at INTA’s Institute of Plant Physiology and Genetic Resources, focuses on whether improving nitrogen nutrition can mitigate the negative effects of water stress (drought) on both yield and grain protein content.
Conducted through field trials in partnership with INTA’s Manfredi Agricultural Experimental Station, the research aims to better understand the physiological mechanisms behind enhanced protein accumulation in high-performing soybean genotypes, according to a press release.
Environmental factors — especially water and nutrient availability during the grain-filling stage — significantly influence yield and grain composition. Previous studies have shown that drought conditions reduce the crop’s ability to fix atmospheric nitrogen, often resulting in earlier harvests, lower yields, and diminished grain quality. However, the underlying biological processes driving these outcomes remain under investigation.
One of the most outstanding findings of the study was that, “the drought during grain filling reduced the yield by 71%, with respect to the irrigation condition, regardless of the availability of nitrogen. However, it was interesting to observe that a greater availability of nitrogen under conditions of water deficit resulted in increases of 12% in the final weight of the grains, 5% in the concentration of protein in the grain and up to 30% in the harvest index, a key indicator of the amount of biomass that ends up in the grains,” explained Verónica Ergo -specialist in Ecophysiology at the Center for Agricultural Research of INTA-.
The study explored the ecophysiological foundations of nitrogen uptake, remobilization, and partitioning, along with the key regulatory processes that enable simultaneous improvements in soybean yield and grain protein content—both under optimal conditions (with irrigation and nitrogen supply) and during water stress.
The findings offer valuable insights for breeders aiming to develop soybean genotypes that not only deliver high yields and superior protein quality but are also resilient to drought conditions. These advances could enhance on-farm value addition and support the long-term sustainability of agricultural systems.
The research formed part of Verónica Ergo’s postdoctoral work, supervised by INTA and Conicet researchers Constanza Carrera and Fernando Salvagiotti. The results were presented at the International Symposium on Genomics for Food Security and Plant-Environment Interaction in a Changing Climate, held in Hong Kong in August 2023. The project received international recognition, winning the award for best scientific poster — underscoring its potential impact on developing high-performance, drought-tolerant soybean varieties.
