The studies conducted on 30 days old embryos in respect of nucleic acid contents (RNA + DNA) showed that in G. barbadense L. it was almost double that in G. hirsutum L. In the case of inheritance of RNA and DNA, female parent contributed more hereditary material than the male parent. Depending upon the female parent, heterosis for nucleic acids (RNA + DNA) in Fo generation was found in crosses G. barbadense L. X G. hirsutum L The F1 genera t-ion showed no increase over the mid parent or better parent in general.