Runners or Seeds? Two Ways to Make New Plants

The Plant Swap at Elm Street Garden

1Every September, the Elm Street Community Garden holds a plant swap. This year, gardener Samir Haddad brought two kinds of young plants: strawberries and peas. He set them on separate tables and posted a sign explaining how each batch had been made.

2The strawberry table held six young plants from his best strawberry plant, which grows large, sweet berries and rarely gets leaf spots. In summer, that plant sent out runners, long stems that creep along the ground. Where a runner touched the soil, it grew roots and leaves and became a new plant. Mr. Haddad cut each runner once its plant had good roots. All six plants that bore fruit made large, sweet berries like the parent's. The same summer he also planted seeds from that plant's berries. The seedlings grew fruit that varied a lot: some small and sour, some medium, and a few large and sweet.

3The pea table came from crosses. In pea plants, the allele for purple flowers (P) is dominant and the allele for white flowers (p) is recessive. Pea flowers usually pollinate themselves, so to cross two plants Mr. Haddad opened young flowers, removed their pollen-making parts and brushed on pollen from a different plant. In Cross 1, both parents had purple flowers, and each had one white-flowered parent, so both were Pp. In Cross 2, he crossed a Pp purple plant with a pp white plant. He planted the seeds from each cross and recorded the flower color of every plant that bloomed.