MALE AND FEMALE FERTILITY VARIATION IN WILD RADISH, A HERMAPHRODITE

Identified in Raphanus raphanistrum a 15-fold range in mean male fertility, nearly a 200-fold range in female fertility, and a 25-fold range in total fertility. Male fertility was correlated with the distance among mates and with a number of phenotypic features of the plants: the total number of flowers produced, flower color, peak flowering time, whether the peak flowering times of the male and female parents overlapped, and some of the interactions of these variables. An additional portion of the variance of male fertility, however, was accounted for by a class variable denoting each male parent, suggesting that unmeasured features of the plants influenced male fertility. Female fertility was distinctly bimodal. Within mode, most of the variance of female fertility was accounted for by number of flowers produced by each plant and its peak flowering period. Male and female fertilities were only weakly correlated, permitting a wide range of functional genders, 0.03-0.91 (possible range, 0-1), to be expressed. Because wild radishes are annuals, such a lifetime fertility variation must have important fitness consequences. -from Authors