Effects of Male Cytoplasm on Inheritance in Hybrid Maize1

It is generally thought the female and not the male gamete contributes the cytoplasm to the offspring. Suppose it is possible for the male parent to contribute some cytoplasm to the progeny. It would be advantageous to know if there is any measurable effect of the male cytoplasm on the progeny of a hybrid resulting from the union of female and male gametes in fertilization. Seed of a double‐cross maize hybrid (Zea mays L.) was prepared to obtain all possible combinations of the male and female cytoplasms. The eight entries were tested in randomized, complete block field experiments in paired plots 2 years with 10 replications/year. All four inbreds in the double‐cross were uniform long‐time inbreds. Data were obtained on 11 and 13 agronomic characters in the two experiments. This investigation indicates that the male cytoplasm can influence the hereditary expression of characters in the progeny. But, the expression of the male cytoplasm may be influenced by the female cytoplasm. One of the problems in the evaluation of cytoplasmic effects in breeding programs may be a cytoplasmic‐environmental interaction from year to year.