Chiasma frequency in the two sex mother-cells of a hermaphrodite

Summary

• 1. Studies have been made of the chiasma frequencies of the two sex mother-cells in each of nine bulbs of the Bluebell, Endymion nonscriptus (L.) Garcke. In six of these the mean values were higher in the embryosac than in the pollen mother-cell, and the overall picture shows the values in the female mother-cells to be only about 1.03 times the values in the male mother-cells.

• 2. Data from the literature so far show that the chiasma frequency in the female mother-cell is either virtually the same as in the male mother-cell or greater by varying degrees. A case of values smaller in the female than in the male mother-cell is yet to be demonstrated.

• 3. A study of the realtionship between the pairs of values in the two sex mother-cells of the same individuals shows an apparent absence of correlation in the present data on the Bluebell.

• 4. Comparison with the results from two other organisms shows that in Dendrocoelum where the size of differences between the chiasma frequencies of the two sex-cells was greatest, a highly significant positive correlation could be demonstrated between the pairs of values, whereas in Lilium longiflorum where a moderate size of differences existed, the correlation was slight. Thus it has been argued that where the differences between the chiasma frequencies of the two sex-cells were small it may become statistically difficult to demonstrate a positive correlation between them as we might expect.