Page:Popular Science Monthly Volume 62.djvu/279

Rh (except in a single individual). Hence the cross VB X GS gives us the hybrid VgSb. When this hybrid produces pollen and ovules, the pair of characters V and G separate, V going to half the pollen grains and ovules, and G to the other half. S and B do the same thing, but without reference to V and G. Hence we have four kinds of pollen grains and four of ovules, as shown in the following diagram:

Here it will be noticed that (2) and (5) give the same result. Similarly, (3) and (9); (8) and (14); (12) and (15); and (4), (7), (10) and (13). We may, therefore, represent the hybrid and its progeny thus:

In like manner the progeny of the other types may be written out.

Of the nine types produced from the hybrid, four of them, VS, VB, GS, GB, are pure, and will reproduce true to seed. They have no characters hidden in them to crop out in later generations. It will be noticed that each of these pure types constitute one sixteenth of the progeny of the hybrid. Four other types, VSb, VgS, VgB