Chemical evaluation of soybean grains from different environments of the Argentinean crop region with focus on oil, protein, fatty acids and isoflavonoids

MARÍA J. MARTÍNEZ; CONSTANZA CARRERA; MÓNICA BALZARINI; JULIO DARDANELLI

Beijing

Conferencia; World Soybean Research Conference VIII; 2009

Institute of Crop Science, Chinese Academy of Agricultural Sciences

Since most of the soybean [Glycine max (L.) Merr.] grains is processed in the agroindustry, there is a growing concern about environmental effects on seed composition. This study describes the environmental variability in oil (O), protein (P), Oleic (OA), Linoleic (LA), and Linolenic (LNA) acids, and total isoflavones (TI) across the soybean crop region in Argentina (29º to 38º S) exploring the relationships of such products with climatic variables recorded during the periods R1 to R7 (R1-R7) and R5 to R7 (R5-R7) of the growing cycle. A data set (crop years 2001-2002 to 2003-2004) was constructed from 82 soybean multi-environment trials including commercial cultivars from several maturity groups (III to VIII). Multiple regressions together with variable selection were used to identify climatic factors with significant associations to seed composition changes. The content in grain varied between 17.7-26.3 % for O, 34.1-45.4% for P, 16,2-35,8% for OA, 41,5-57,4% for LA, 4,7-11,5% for LNA acids, and 0,76 - 8,02 mg/ g of dry defatted flour (mg/gMS) for TI. In environments without water stress [potential evapotranspiration less rainfall during the period (pp-ETPR1R7)> 70 mm], increases in mean daily air temperature during R5-R7 (TmR5R7) explained increased values of O and OA and decreases in LA, LNA and TI. Under water stress the most explicative models included TmR5R7, but pp-ETPR1-R7 was also important to model seed composition. The relationship P- TmR5R7 was quadratic indicating that P decreases with increasing temperature between 14ºC and 19ºC; then P increases but conditioned to the water stress level.