[Competition between haploid cells in the ovary of Oenothera].

Investigations were made on the segregation of the genes s, de and of the translocation point of the first linkage-group in the progeny of backcrosses of heterozygotes of Oenothera with the complexes (h) hookeri and flavens with Oe. hookeri sulfurea ♂. The deviations from mendelian expectation are statistically significant. The phenotype corresponding to the hookeri-parent of the F1 occurs with the greatest relative frequency.An interpretation of the results is given on the assumption that in the first linkage group, which appears cytologically as a translocation group of four chromosomes, a gene with gametophytic action is located. The complex (h) hookeri contains the allel ga-♀(+), the complex flavens ga-♀(-). These alleles influence the development of the haploid cells in the ovary in such a way that in a heterozygote mother plant the haploid cells with the allel ga-♀(+) have a greater chance to form the embryosac and the egg cell than haploid cells with the allel ga-♀(-).There is a strong negative interference in the parts of the chromosomes adjacent to the translocation point.The variability of the recombination of the three loci leads to the assumption of highly variable crossover-values in the chromosomes here investigated. A correlation between this variability of crossing-over and of the negative interference with pairing anomalies in a translocation group is taken into consideration.Hypotheses concerning the genetic basis of the competition between haploid cells in the ovary and the anther and the action of these gametophytic genes are discussed.