In the experiments above described plants were used which differed only in one essential character[36]. The next task consisted in ascertaining whether the law of development discovered in these applied to each pair of differentiating characters when several diverse characters are united in the hybrid by crossing. As regards the form of the hybrids in these cases, the experiments showed throughout that this invariably more nearly approaches to that one of the two parental plants which possesses the greater number of dominant characters. If, for instance, the seed plant has a short stem, terminal white flowers, and simply inflated pods; the pollen plant, on the other hand, a long stem, violet-red flowers distributed along the stem, and constricted pods; the hybrid resembles the seed parent only in the form of the pod; in the other characters it agrees with the pollen parent. Should one of the two parental types possess only dominant characters, then the hybrid is scarcely or not at all distinguishable from it.
Two experiments were made with a larger number of plants. In the first experiment the parental plants differed in the form of the seed and in the colour of the albumen; in the second in the form of the seed, in the colour of the albumen, and in the colour of the seed-coats. Experiments with seed characters give the result in the simplest and most certain way.
In order to facilitate study of the data in these experiments, the different characters of the seed plant will be indicated by A, B, C, those of the pollen plant by a, b, c, and the hybrid forms of the characters by Aa, Bb, and Cc.
Expt. 1.—AB, | seed parents; | ab, | pollen parents; | |
A, | form round; | a, | form angular; | |
B, | albumen yellow. | b, | albumen green. | |
The fertilised seeds appeared round and yellow like those of the seed parents. The plants raised therefrom yielded seeds of four sorts, which frequently presented themselves in one pod. In all 556 seeds were yielded by 15 plants, and of these there were:—
315 round and yellow,
101 angular and yellow,
108 round and green,
32 angular and green.
All were sown the following year. Eleven of the round yellow seeds did not yield plants, and three plants did not form seeds. Among the rest:
| 38 had round yellow seeds | AB |
| 65 round yellow and green seeds | ABb |
| 60 round yellow and angular yellow seeds | AaB |
| 138 round yellow and green, angular yellow and green seeds | AaBb. |
From the angular yellow seeds 96 resulting plants bore seed, of which:
| 28 had only angular yellow seeds | aB |
| 68 angular yellow and green seeds | aBb. |