These seeds unfortunately did not germinate on sand at the same time with the crossed seeds, so that they could not be planted simultaneously. One of the two crossed seeds in a state of germination was planted in a pot (Number 1) in which a self-fertilised seed in the same state had been planted four days before, so that this latter seedling had a great advantage over the crossed one. In Pot 2 the other crossed seed was planted two days before a self-fertilised one; so that here the crossed seedling had a considerable advantage over the self-fertilised one. But this crossed seedling had its summit gnawed off by a slug, and was in consequence for a time quite beaten by the self-fertilised plant. Nevertheless I allowed it to remain, and so great was its constitutional vigour that it ultimately beat its uninjured self-fertilised rival. When all four plants were almost fully grown they were measured, as here shown:--
TABLE 5/54. Lathyrus odoratus.
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Crossed Plants.
Column 3: Self-fertilised Plants.
Pot 1 : 80 : 64 4/8.
Pot 2 : 78 4/8 : 63.
Total : 158.5 : 127.5.
The two crossed plants here average 79.25, and the two self-fertilised 63.75 inches in height, or as 100 to 80. Six flowers on these two crossed plants were reciprocally crossed with pollen from the other plant, and the six pods thus produced contained on an average six peas, with a maximum in one of seven. Eighteen spontaneously self-fertilised pods from the Painted Lady, which, as already stated, had no doubt been self-fertilised for many previous generations, contained on an average only 3.93 peas, with a maximum in one of five peas; so that the number of peas in the crossed and self-fertilised pods was as 100 to 65. The self-fertilised peas were, however, quite as heavy as those from the crossed pods. From these two lots of seeds, the plants of the next generation were raised.
PLANTS OF THE SECOND GENERATION.
Many of the self-fertilised peas just referred to germinated on sand before any of the crossed ones, and were rejected. As soon as I got equal pairs, they were planted on the opposite sides of two large pots, which were kept in the greenhouse. The seedlings thus raised were the grandchildren of the Painted Lady, which was first crossed by the Purple variety. When the two lots were from 4 to 6 inches in height there was no difference between them. Nor was there any marked difference in the period of their flowering. When fully grown they were measured, as follows:--
TABLE 5/55. Lathyrus odoratus (Second Generation).
Heights of plants measured in inches.
Column 1: Number (Name) of Pot.
Column 2: Seedlings from Plants Crossed during the two previous Generations.
Column 3: Seedlings from Plants Self-fertilised during many previous Generations.
Pot 1 : 72 4/8 : 57 4/8. Pot 1 : 71 : 67. Pot 1 : 52 2/8 : 56 2/8.
Pot 2 : 81 4/8 : 66 2/8. Pot 2 : 45 2/8 : 38 7/8. Pot 2 : 55 : 46.
Total : 377.50 : 331.86.
The average height of the six crossed plants is here 62.91, and that of the six self-fertilised 55.31 inches; or as 100 to 88. There was not much difference in the fertility of the two lots; the crossed plants having produced in the greenhouse thirty-five pods, and the self-fertilised thirty-two pods.
Seeds were saved from the self-fertilised flowers on these two lots of plants, for the sake of ascertaining whether the seedlings thus raised would inherit any difference in growth or vigour. It must therefore be understood that both lots in the following trial are plants of self-fertilised parentage; but that in the one lot the plants were the children of plants which had been crossed during two previous generations, having been before that self-fertilised for many generations; and that in the other lot they were the children of plants which had not been crossed for very many previous generations. The seeds germinated on sand and were planted in pairs on the opposite sides of four pots.