Cross-Pollination of Pea Plants

Parent Plants

• According to the Palomar College website, Mendel decided to test seven different characteristics in his pea plants. These characteristics included flower color, flower position, plant height, seed shape, pod shape, seed color and pod color. As Mendel bred the plants, he found that flowers could be white or purple while the plants themselves might be tall or short. The seeds could be round or wrinkled and the pods could be flat or full. Seeds and pods could also be yellow or green, though the color of the pod didn't determine seed color. Mendel observed that different plants showed different combinations of these characteristics.

Pollination Method

• According to Julian Trubin, Mendel used a paintbrush to transfer pollen from a pea plant with one set of characteristics to a pea plant with a completely different set. He kept careful track of which characteristics the parent plants possessed and planted the seeds that resulted from the pollination. As the new plants grew, Mendel observed which traits appeared to be passed down.

Dominant Traits

• Mendel studied pea seed shape first, according to Vision Learning. He noted that, though he'd pollinated a round-pea plant with a wrinkled-pea plant's pollen, the offspring of the union showed only round pea plants. He also noted that green pea plants pollinated with yellow pollen only produced yellow peas. Yellow also showed as the dominant color for pods while purple flowers dominated over white.

Recessive Traits

• Curious as to what happened to the other traits, Mendel pollinated several plants of the second generation with their own pollen, according to Vision Learning. Despite the fact that these plants showed only dominant traits, their offspring showed some of the traits that the first, or grandparent, generation possessed. These plants had wrinkled peas, white flowers and green seeds and pods. Mendel discovered that these traits were recessive, which means that both parents must carry a trait for it to show up in the offspring. He also discovered that two parents with seemingly all-dominant features could produce offspring with recessive traits if the grandparent plants had these traits.