Relationship between Sterility and Seedlessness in Citrus

Abstract

The relationship of female and male sterility, and self-incompatibility to seed content in citrus were investigated using 22 male sterile and fertile cultivars. The male fertile cultivars were grouped into self-compatible and self-incompatible. Positive correlation (r = 0.927^**, r²=0.859) existed between the average number of seeds per fruit obtained by hand pollination, which indicated the degree of female fertility, and that yielded by open pollination. This result indicates that the degree of female fertility and sterility can be estimated from seeds derived by open pollination. The difference between the average number of seeds per fruit by hand pollination and that by open pollination was greater in male sterile cultivars and in self-incompatible cultivars than it was in self-compatible cultivars. This indicates that self-incompatibility as well as male sterility is effective on the reduction of seediness. In open pollination, self-compatible cultivars produced very few seedless fruits, whereas male sterile and self-incompatible cultivars produced many seedless fruits.