[Competition between pollen tubes of Oenothera, dependent on the maturation of the style].

In backcrosses of hybrids, which show a competition of genotypes in the pollen, the segregation depends on the developmental condition of the style at the time of pollination.The pollination of young styles with pollen of the hybrids gives a more normal segregation. The results are compatible with the hypothesis, that the relative inhibition under the influence of the allel ga (-) acts at the germination of the pollen grains and the first stages of development of the pollen tubes in the style.