Yes, self-incompatibility imposes restrictions on autogamy. The reason for this may be as majority of flowering plants produce hermaphrodite flowers and when pollen grains come in contact with the stigma of the same flower they continue self-pollination. Such type of continued self-pollination results in Inbreeding depression. That’s why flowering plants have developed many devices to discourage self-pollination and to encourage cross-pollination. One of the major ways to prevent self-pollination is self-sterility or self incompatibility, i.e. in some bisexual flowers, if the pollen grains fall on the stigma of the same flower, germination does not occur. But the same pollen grains germinate when they fall on the stigma of other flowers of the same species. It is a genetical mechanism to prevent self-pollination and promote cross-pollination.