Flowering plants have been classified as self-incompatible if they do not set seed following self-pollination, and self- compatible if they do. Recent work shows that this fundamental distinction is oversimplified. Some plants, including the glacier lily, can produce selfed seeds if only self pollen is applied to the stigma, but will preferentially produce outcrossed seeds from a mixture of self and outcross pollen. The proposed research uses genetic markers, pollen-color markers, and DNA- staining fluorescent pollen-nucleus markers. Novel techniques for transplanting styles and for determining the genetics of aborted seeds will be combined with the markers to isolate the post-pollination stage(s) at which preferential ourcrossing is expressed following mixed pollinations. The possible role of inbreeding effects will receive special attention. The result should constitute the most complete investigation to date of a little known, cryptic "incompatibility" process that can potentially determine the level of inbreeding in a population. Such knowledge will enrich any attempts to understand the function and evolution of plant reproductive systems, and may have practical utility in agricultural plant breeding, especially in the production of inbred lines for hybrid seed production.
