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Soy: study how solar radiation impacts grain quality

Argentina Spanish

With a 49% share in the global oil and soybean flour market, for 20 years, Argentina has been leading exports of these specialties. In line with the new demands of consumers who prefer products with healthier characteristics, a team of researchers from INTA-Conicet and Embrapa - Brazil - study how the environment influences the nutritional composition of soybeans, the most sown crop nationwide. Constanza Carrera, a specialist in plant ecophysiology at the Institute of Plant Physiology and Genetic Resources of INTA and researcher at Conicet, explained that both oil and soy flour contain compounds with great nutritional value. "Unsaturated essential fatty acids (linoleic and linolenic) and isoflavonoids are compounds highly valued for their health benefits and are used by the functional and nutraceutical food industry," she said.

During crop growth, the environment has a significant influence on the expression of traits that contribute to the weight of soybeans and determine their industrial and/or nutritional value. At this point, according to Carrera, intercepted solar radiation is one of the most influential factors and, however, has been little studied, especially in relation to the attributes that define the chemical quality of soybeans. "Our research is focused on quantifying what effects the intercepted solar radiation has on the weight of grains, protein, oil, unsaturated fatty acids and isoflavonoids," said Carrera and added: "With this information we can contribute to the design of practices of management to improve crop yield and obtain products with a specific and differential quality ”.

In a trial conducted in the field of the INTA Manfredi experimental station in Córdoba, the work team led by Carrera determined that a slight defoliation intensity of 33% (which represented only a 4% reduction in intercepted solar radiation ), regardless of the moment of occurrence within the filling of grains, did not affect the weight of grains, the content and concentration of protein and oil, neither the levels of isoflavonoids. However, the quality of the oil was affected in terms of the main fatty acids that compose it, decreasing the concentration of oleic and increasing that of linoleic.

"These results together with the identification of the intercepted photosynthetically active radiation could be integrated to optimize crop management in environments where the photosynthetic capacity of the leaves (source of assimilates) can be compromised and with it the productivity and final grain quality" , concluded the researcher of INTA and Conicet.