ABSTRACT
Background Most owering plants that are predominantly self-pollinating have an annual life history [1-3]. Interpretations of this association usually involve one of two main hypotheses. (i) Compared with perennials, annuals may generally accrue greater tness benets from selng through ‘reproductive assurance’, i.e., because ovules may be generally more outcross-pollen-limited and/or pollen grains may be more outcross-ovule-limited [2,4-8]. (ii) Perennials may incur a higher tness cost of
selng through seed discounting and inbreeding depression; hence, possibly most selfers are annuals simply because relatively few perennials can be selfers [9,10].
