Inheritance of the Trait of Male Sterility in Cryptomeria japonica

Abstract

Matings of male-sterile C. japonica and fertile elite C. japonica, as well as backcross seedlings of male-sterile trees, were carried out to clarify the genetic trait of male sterility of the C. japonica. The seeds from male-sterile C. japonica were germinated in an incubator and grown them in the greenhouse between 1994 and 1997. The seedlings were treated with 100 ppm gibberellin at early July 1994 and early July 1995 to promote the formation of male flowers. In the middle of January 1995, the male flowers of all seedlings were examined under the microscope to confirm the production of pollen. In January 1996, pollen did not developed in to the male flowers from the seedlings between the fertiled elite and backcross C. japonica. In January 1997, all seedlings of elite C. japonica produced pollen in their male flowers; however, pollen did not developed in 55 out of 120 backcrossed seedlings. This evidence suggests that the heredity pattern of male sterility in C. japonica is nuclear male sterility controlled by a pair of recessive genes.