Functional activity of the genetic apparatus of cell during heterosis of various agricultural crops

The paper presents the results of a comprehensive study of functional activity of the genetic apparatus, taking into account the localization of its components in the nuclei, mitochondria and chloroplasts to determine their possible role in yield formation during heterosis in tomato, cucumber, eggplant and wheat. A clear pattern was revealed in terms of DNA content per cell in all hybrids, regardless of the species and the degree of heterosis exceeded their parents. Tomato hybrids exhibited activation of genetic material synthesis in mitochondria, while wheat hybrids showed activation in both mitochondria and chloroplasts. Establishing the pattern of DNA synthesis activity in heterotic hybrids in comparison with parental varieties allows us to recommend determining the DNA content in a somatic cell for predicting heterosis. The results of the present study indicated that in the case where the nuclear, mitochondrial and chloroplast genetic systems of a plant cell function with an increased load in a hybrid, which thereby receives more energy to enhance the processes of biosynthesis of plastic substances, one can, as a consequence, expect the manifestation of a high heterotic effect. These data are consistent with James’s hypothesis that one of the causes of heterosis is the redundancy of the genetic code, and Kihara H.’s hypothesis on nuclear-cytoplasmic heterosis.