Molecular approaches to the study of sex determination in dioecious Silene latifolia

We initially chose Silene latifolia (white campion) as a model for the study of plant sex determination mechanisms for several reasons. Though recent studies on maize ( Chapter 2 ), cucumber ( Chapter 13 ) and kiwi fruit ( Chapter 11 ) have clearly demonstrated the accessibility of sex determination mechanisms in monoecious plants, we anticipated that a strictly dioecious species would allow a greater number of approaches to the study of sex determination. The choice of suitable dioecious species is limited, as only 4% of angiosperms are dioecious ( Yamplosky and Yamplosky, 1922 ), and the majority of these are tree species ( Bawa, 1980 ) and therefore impractical for molecular genetic analysis. Although a number of important crop plants are dioecious, including hops, hemp, asparagus, spinach, date palm and papaya ( Ainsworth et al ., 1998 ; Dellaporta and Calderonurrea, 1993 ; Grant et al ., 1994a ), we chose the wild herbacious species S. latifolia for our studies for the practical reasons of its suitable growth habit, relatively rapid life cycle and simplicity of cultivation.