Research from the Faculty of Agricultural Sciences deepens improvements in soybean yield by incorporating pods with four seeds.

An innovative study carried out by researchers from the Faculty of Agrarian Sciences of the Universidad Nacional de Rosario seeks to take advantage of genetic and biotechnological characteristics to increase the productivity of soybean crops, facing and challenging old preconceptions related to crop performance. 

This research opened new possibilities for improving soybean yield by incorporating four-seeded pods. In collaboration with the Don Mario Group, the project is moving towards the commercial application of these improvements, promising a significant impact on Argentine agriculture.

The team is made up of Julieta Bianchi, who is the project director, Alvaro Quijano, Carlos Cairo, Carlos Gosparini, Nidia Montechiarini and Juan Pablo Ortiz. In turn, Bianchi, Gosparini, Ortiz, and Cairo also belong to the double dependency Institute for Research in Agrarian Sciences of Rosario (UNR – CONICET). Students from UNR's Agronomic Engineering degree also participate.

The research began when Bianchi began his doctorate in Agricultural Sciences and decided to study the benefits of incorporating soybean pods with four seeds for commercial use. “Soybean pods can contain from one to five seeds, although two of those consecutive categories generally predominate in a plant. Our study analyzed commercial varieties and we observed that, most of them have pods with three seeds, some with two, but very few with four. “We believe that the inclusion of four-seed pods could significantly improve yield due to its direct association with seed number.”

The researcher explained that the yield of any crop depends on the number of seeds and their unit weight. In turn, the number of seeds depends on the number of pods and the number of seeds in each one. “Depending on the number of seeds per pod, yield will be affected. We observed that plants with four-seed pods increase yield compared to three-seed pods. Although it seems simple, the physiology and genetics of the characteristic are complex, so we carried out studies to verify if increasing one seed per pod really impacts yield.”

Thus, the research team began field studies with soybean lines that had different amounts of seeds per pod and a positive impact on yield was observed under these experimental conditions. “We obtained these lines from our germplasm bank, a repository of materials preserved for trials. Although they do not have all the properties of current commercial varieties, they have many four-seed pods. “We also began to work on the molecular part to advance faster in improvement, using biotechnological tools such as molecular markers, which allow us to identify early if a plant has the desired characteristic.”

Through molecular markers, they identified the DNA regions that determine the characteristic of pods with four seeds, which would accelerate the improvement process. “This is what I did during my doctoral fellowship and then continued in my postdoctoral fellowship. "We gathered all the necessary information to bring this technology of high percentage of pods with four seeds to commercial germplasm."

Bianchi explained to this medium that the character that they want to incorporate is very stable, with low environmental influence, which would guarantee that once introduced in a breeding plan and in commercial varieties, it will be maintained regardless of the productive environment in which it is grown. Preliminary studies also indicated that increasing the percentage of pods with four seeds does not affect other characteristics such as grain weight or number of pods.

The scientific team achieved a plant that perfectly supports the weight of one more bean per pod. The tests were carried out in the experimental field located in Zavalla. “This development has an impact on potential yield, that is, it improves the productive capacity of soybean varieties.”

Since all the tests were carried out on experimental material, it was necessary to see what happened when this characteristic was incorporated into commercial varieties. Thus the possibility arose of making an agreement with the Don Mario Group (GDM) to work together. “GDM is the main company producing soybean varieties in Argentina. “It has supported us in the development of this research, and it is one of the few companies in the country with national capital.”

The idea is to take the research on a large scale, introducing the four-seed pods developed in experimental lines to commercial lines. To do this, two stages are proposed: the first is to obtain the commercial line with four-seed pods, and the second is to carry out trials throughout the country to study its performance in comparison with varieties that do not have the character incorporated.

Generally, the highest-yielding varieties are moved directly to the market, although it is not always known how that higher yield is generated. “Improving performance involves studying how each component affects it, which often does not coincide with market logic. It is generally thought that if we increase the number of seeds, the weight is likely to decrease because the plant must feed more seeds. These preconceptions need to be tested, and that's what we did. We conclude after the studies carried out that increasing the number of seeds does not reduce weight. We try to break with established dogmas, and we believe that the University and CONICET are there to fulfill that function.”

This project was initiated by Agricultural Engineer Eligio Morandi, who had a long career at UNR as a professor of Plant Physiology in the Faculty of Agrarian Sciences. Until his death in 2023, he served as principal researcher at the Rosario Agricultural Sciences Research Institute. “When we started, we did it from scratch: we had the plant material but we didn't know anything about how the trait behaved. A lot of progress has been made and there is a lot of work and resources invested in this. I can be here today thanks to the fact that I trained at the Public University and that CONICET opened the doors for me. I think we have to defend everything it does because it allows us to investigate without being tied to the immediate," explained Bianchi, and added: "We always seek to carry out applied research that has an impact on the local, regional and national productive system. It is crucial to continue investing as a State in science and technological development, since these advances are fundamental for progress. Likewise, the support of the private sector is necessary, since there are many initiatives and projects that would be unviable without the collaboration and commitment of all the actors involved. Only through a joint effort can we achieve innovative and sustainable results that promote the comprehensive development of our society.”

By Gonzalo J. García