Soybean Tocopherol Concentrations Are Affected by Crop Management

Abstract

Soybeans are an important source of tocopherols, which have health-beneficial properties. Previous studies have demonstrated that environmental factors may affect soybean tocopherol concentrations; the impact of specific crop management strategies, however, remains poorly understood. Experiments were conducted for 2 years at three sites in Quebec to determine the impact on soybean tocopherol concentrations of seeding rate, row spacing, seeding date, cultivar, and P and K fertilization. Total and alpha-, gamma-, and delta-tocopherol concentrations were determined by high-performance liquid chromatography. Overall, alpha-tocopherol was the most responsive to the factors evaluated; the response of other tocopherols was often lower or inconsistent across environments. The seeding rate affected alpha-tocopherol concentrations in three out of five environments; seeding at a rate of 40 seeds m(-2) resulted in 4% higher concentrations than seeding at a higher rate. Wide row spacing (more than 36 cm) resulted in two out of five environments in 6% higher alpha-tocopherol concentrations as compared to narrower row spacing. The seeding date had a greater impact; mid- to late-May seeding across four environments resulted in 45% greater alpha-tocopherol concentrations than seeding at later dates. Phosphorus and K fertilization had a negligible impact on tocopherol concentrations. Across experiments, large differences were observed between environments; plants grown in northern environments consistently had lower concentrations of alpha- and gamma-tocopherols but higher concentrations of delta-tocopherol. Differences between cultivars were also consistent, ranging between 10 and 30%, depending on the tocopherol. Results demonstrate that soybean tocopherol concentrations are affected by crop management and thus suggest that specific recommended agronomic practices may need to be established for the production of soybeans for the functional food market.

Natural diversity of seed α-tocopherol ratio in wild soybean (<i>Glycine soja</i>) germplasm collection

“…It is important to breed cultivars that produce seeds with stably high α-tocopherol ratios across different growing conditions, since the temperature during seed maturation influences its content (Almonor et al 1998, Britz and Kremer 2002, Britz et al 2008, Seguin et al 2010). The selected accessions had different sensitivities to temperature during maturation.…”

“…Conversely, soybeans grown in cooler environments had a lower α-tocopherol content (Seguin et al 2010). Since it is important to breed cultivars that produce seeds with stably high α-tocopherol contents across different growing conditions, we evaluated the thermo-sensitivity of α-tocopherol ratios in seeds of wild accessions with high α-tocopherol ratios.…”

Quantitative trait loci underlying soybean seed tocopherol content with main additive, epistatic and QTL × environment effects

“…Traditionally, genetic improvement of soybean has relied on phenotypic selection of population pedigree from the cross between commercial cultivars or experimental lines (Falconer, Mackay, & Frankham, ; Stuber, Lincoln, Wolff, Helentjaris, & Lander, ). Individual and total Toc behaved as complex quantitative traits and were significantly affected by genotype (Kumar, Rani, Dixit, Bhatnagar, & Chauhan, ; Wang et al., ), environment (temperature and humidity, Almonor, Fenner, & Wilson, ; Britz, Kremer, & Kenworthy, ; Chennupati, Seguin, & Liu, ), genotype by environment interaction (Britz & Kremer, ; Shaw, Kakuda, & Rajcan, ) and some agronomic managements such as planting rate, seeding rate and row spacing (Dolde, Vlahakis, & Hazebroek, ; Dwiyanti et al., ; Scherder, Fehr, Welke, & Wang, ; Seguin, Tremblay, Pageau, & Liu, ). Additionally, among four Toc components, α‐Toc was the most responsive to the environment (Seguin et al., ).…”

Tocopherol Content as Affected by Different Sowing Dates and its Correlation with Other Quality Traits in Soybean [Glycine max (L.) Merrill]

“…Environmental factors such as drought (Britz et al, 2008) and agronomic practices including planting date, row spacing and planting density (Seguin et al, 2010) are known to influence tocopherol levels. Tocopherol content has been shown to differ over environments characterized by different temperature and photoperiod (Whent et al, 2009).…”