Seed tocopherol assessment and geographical distribution of 1151 Chinese soybean accessions from diverse ecoregions

Natural Variation of Seed Tocopherol Composition in Diverse World Soybean Accessions from Maturity Group 0 to VI Grown in China

“…This finding is consistent with earlier research [13,16]. Accession ZDD00041 from China belongs to MG 0 (Table S3) and had the highest level of α-tocopherol, originating in the high latitude Northern Region (NR), which represents hotspots for the origin of accessions with increased α-tocopherol accumulation [21]. Moreover, α-tocopherol showed the highest coefficient of variation (CV) (42.04%) (Table 1), implying that α-tocopherol exhibits a more natural variation across environments than other tocopherol isomers, which is also supported by previous studies [13,22].…”

“…This demonstrates the possibility of decreasing δ-tocopherol levels with increasing α-tocopherol levels. Such an inverse connection between αand δ-tocopherols was also evident in numerous previous studies [11,17,21,22].…”

“…In the current study, the USA accessions had the lowest mean content of α-tocopherol and may be attributed as part of the reasons for a lower intake of α-tocopherol by US adults [29]. In contrast, the Russian accessions had the highest mean content of α-tocopherol due to the accumulation of increased α-tocopherol by the accessions that originated in the higher latitude regions [21].…”

“…Similarly, δ-tocopherol levels ranged from 21.87 μg g −1 to 136.67 μg g −1 with an average of 75.11 μg g −1 (Table 1). The lowest content of δ-tocopherol was obtained in the accession WDD02708 (21.87 μg g −1 ) from Russia, perhaps due to the presence of low δ-tocopherol in the accessions of high-latitude regions [21], and the highest content was found in ZDD06638 (136.67 μg g −1 ) from China (Table S2). In the current study, the proportional percentages of α-, γ-, and δ-tocopherols were 4.73%, 62.47%, and 32.78%, respectively, across environments and genotypes (Table 1), which were within the same range as the values reported previously [10,13,25].…”

“…These findings reflect contrasting trends of tocopherols with different MGs and further emphasize the significance of MGs as a determining factor in soybean seed tocopherol composition. Early maturing soybean accessions had higher levels of α-, γ-, and total tocopherols due to the exposure of early MG genotypes to long day length and higher solar radiation conditions at high latitude region during seed filling period (R5-R8 stage), which leads to higher tocopherol levels [35][36][37] and due to origin and distribution of early MG accessions in the high-latitude regions [21]. High-latitude regions (NR of China, Far-East region of Russia, and Northern USA) were not considered suitable for the production of late MG genotypes because they exhibit short frost-free periods that are not long enough for the maturation of late-maturing accessions.…”