Environmentally induced changes of sex expression in atriplex canescens

Abstract

The western North American shrub Atriplex canescens is predominantly dioecious, but most populations contain some monoecious individuals. A tetraploid half-sib family consisting of 665 individuals was evaluated annually for floral phenotype (sex expression) from 1972-75. The autumn/winter of 1972-73 started out mild and wet and then turned unusually cold. The half- sib family expressed a very different sex ratio in the 1973 growing season than in the three other years. A sex-determining mechanism is proposed of XXXX for pistillate plants, XXYY for staminate plants, and XXXY for monoecious plants and those that vacillate among floral phenotypes from year to year. © 1977, The Genetical Society of Great Britain. All rights reserved.