We studied the inheritance of obligate apomixis, using both selfed and F 1 progenies. In both cases, the female parent was a completely sexual plant heterozygous for genes controlling method of reproduction, and the male parents in the crosses were obligate apomicts. Classification of S 1 and F 1 plants for mode of reproduction was achieved by embryo‐sac analyses, or study of progeny variability, or both. Four hundred and sixty‐nine S 1 progeny, involving two populations grown in the years 1962 and 1965, respectively, segregated for sexual to apomictic types at ratios not significantly different from a 13:3. One hundred and forty‐five S 1 progeny grown in 1963 gave a sexual to apomictic ratio of 8.66:l. Pooled data for these 614 S 1 progeny of the sexual plant fit the 13:3 ratio. Seven hundred and sixty‐six F 1 hybrids between the sexual plant and two obligate apomictic ecotypes, blue and common, gave sexual to apomictic ratios not significantly different from a 5:3. Interpretation of the 13:3 S 1 and 5:3 F 1 sexual to apomictic ratios is as follows. The genetic constitution of the sexual plant is hypothesized to be AaBb , where gene B conditions sexuality, and it is epistatic to gene A , which controls apomixis. The genetic constitution of the apomictic male parents is hypothesized to be Aabb . Results obtained support the hypothesis and suggest that the sexual plant originated by mutation at the b locus. The manipulation and use of obligate apomixis in a buffelgrass breeding program is discussed.
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Taliaferro et al. (1966) studied this question.