Soybean Seed Composition under Different Water Conditions

LOPEZ, E.; ANGELOZZI, V.; ANTONELLI, M.; ALVAREZ PRADO, S.; GERDE, J.A.

Rosario

Congreso; XXXIV Argentinian Meeting of Plant Physiology; 2023

Water deficit during seed filling usually reduce seed size because of a shortening of the duration of this stage (Rotundo & Westgate, 2010). The impact of water deficit over seed composition differs according to the timing and intensity of drought stress as well as the genotype used (Medic et al, 2014). The objective of this study was to characterize the dynamics of seed filling dissected in its composition (oil, protein and soluble carbohydrates) in soybean (Glycine max (L.) Merr.) under different water scenarios. The experiment was conducted at the Villarino Experimental Field, located in Zavalla, Santa Fe, Argentina (33°1 S, 60°53 W), on a Vertic Argiudol soil. Three commercial soybean genotypes with different seed composition (SYN 5X1; DM 40R16; DM 4619; López et al, 2021) were evaluated in environments with contrasting water availability: fully irrigated (IR), rainfed (RA) and water restricted (WR) (between flowering (R1) and physiological maturity (R7); Fehr & Caviness, 1977). The rate and duration of seed filling were affected by the explored environment (35 and 91% SS, respectively), as well as final seed weight (91% SS). Regarding seed composition, variability in final protein, oil and carbohydrates content was mainly driven by the environment through its impact over the filling duration, while the rate of accumulation showed a strong genotypic component for oil and protein. Finally, the rate of accumulation of soluble carbohydrates was independent of the genotype and the environment. For the conditions evaluated, seed weight was higher in cases of more available water and, as expected, where the duration of filling was longer. In terms of composition, genotype establishes the rate of accumulation of both oil and protein, while environment determines their final concentration. Finally, none of the effects studied modified the rate of soluble carbohydrate accumulation.