Environmental and Management Factors Associated with Increased Seed Protein Concentration in Soybean.

BOSAZ LINA B.; ROTUNDO JOSÉ LUIS; BORRÁS LUCAS; GERDE JOSE A.

Baltimore

Conferencia; 2018 ASA and CSSA Meeting; 2018

American Society of Agronomy

Soybean processing involves oil extraction and the subsequent production of protein meal. High protein meal, used for animal feeding, can be achieved only with seed protein concentration above certain level. Low seed protein concentration precludes the production of high protein meal required for profitable marketing. Seed protein concentration has a strong genetic component but it is also affected by environmental and management factors. The objective of this presentation is to: i) describe the physiological base of genotypic differences in seed protein concentration; ii) explore regional spatial variation in protein concentration in North and South America; and iii) assess environmental and management factors affecting seed protein concentration in soybean. Part of the genotypic differences in soybean seed protein concentration was associated with contrasting source-to-sink ratio, set during early reproductive developmental stages. Increased source-to-sink ratio was required to express high seed protein concentration. However, high source-to-sink ratio are usually attained by reducing the number of seeds set instead of by increasing leaf area. This result helps to explain the negative correlation usually between seed protein concentration and yield. At a regional scale, seed protein concentration increases at low latitude both in North and South America. This regional pattern is attributed to higher temperatures during seed filling and lower yields. The evaluation of different management practices to modify seed protein concentration showed a major role for cultivar selection in spite of the negative correlation with yield. Besides cultivar selection, planting date and fertilization during the seed filling period emerged as alternatives to manage seed protein concentration. Ultimately, increasing seed protein concentration while maintaining seed yield requires improving total nitrogen capture during the cropping season via breeding or agronomic management.