Inheritance of expressivity of tph2 mutation in crosses with a normal sunflower genotype

Genotypic differences in expressivity of tph2 mutation in sunflower seeds were in decreasing of у-form from 90 to 68 % for VK639 sublines and from 69 to 47 % for VK876 sublines. All F1 seeds in the crosses with LG26 had normal phenotype. In F2 seeds in the crosses of VK639×LG26 and VK876×LG26 for both sublines mono- and digenic segregation were observed. Content of γ-tocopherol in F2 seeds for tph2 homozygotes in crosses with minimum expressivity was lower than for maximum. This fact is an evidence of modifier gene action on tph2 expressivity in inheritance in the case of the cross with a normal line