DNA synthesis and nuclease activity during germination of a heterotic F1 hybrid of maize

Abstract

In maize, the DNA content and [3H]thymidine incorporation in embryonic cells and the nuclease activity in the fraction extracted from embryonic cells were determined in a heterotic F1 hybrid (Oh545 × W22) and its parental inbred lines. DNA content was higher in the F1 hybrid than in parental lines; however, [3H]thymidine incorporation was greater in W22 than in the F1 hybrid. Herring DNA splitting activity was higher in W22, and the yeast RNA hydrolyzing activity was almost the same in the F1 hybrid and W22. Oh545 had the lowest value in each of these parameters. It is suggested that qualitative and quantitative differences in DNA synthesis during the germination period between the F1 hybrid and the parental lines are related to the expression of heterotic vigor.