Hybridological analysis of expressivity of tph2 mutation in different genetic backgrounds in sunflower

The constant sublines of sunflower with maximum and minimum expressivity of tph2 mutation for VK175 tph2 and VK876 tphl tph2 lines were developed. Different level of expressivity of tph2 mutation was shown to be inherited intermediately in Fl. Continual F2 variation without discrete phenotypic classes was observed. The mean value of Fl, F2 and the parent's mean did not differ. That indicates at the additive action of the modifier genes controlling the differences in λ-tocopherol content between corresponding sublines of VK175 and VK876.