Genotypic and environmental variability of the total content of tocopherols in the seeds of inbred sunflower lines

Breeding for high total content of tocopherols (vitamin E) in sunflower seed oil involves studying the genetics of this trait. Twenty-nine inbred lines of sunflower with different total tocopherol content (TTC) were selected from 60 samples of the original material and studied at VNIIMK, Krasnodar, in 2016-2019. TTC was determined in an average sample from a head of shelled seeds by direct hexane extraction and further measurement of the optical density of the colored solution on a spectrophotometer. Both the genotype and the growing conditions influence the TTC in the seeds. The average range of variation over four years was from 302 to 605 mg kg ^-1. The largest differences, 2.6 times, between genotypes were found in 2018 with a range of variability from 258 to 667 mg kg^-1. Significant differences were found between the average values of 360 mg kg^-1 in 2017 and 432 mg kg-1 in 2019. The genotype and the year of growing have the greatest influence on the TTC, measured as 65% and 8%, respectively, and the genotype-year interaction accounts for 14% of the effect. The TTC correlation coefficient in the parent-offspring series was 0.65–0.85, and the heritability coefficient in the studied lines was 42–72%. The data on the valuable genetic control of TTC in seeds can help predict the effectiveness of breeding to improve this trait.