How the Mendelian Genetics of Sedum Plants Led to Major Breakthroughs in the Genetics Field
Before devoting his time to studying the common garden peas, Mendel had several important preliminary studies that led to important lessons. These discoveries were then critical in the conduct of his experiment with peas and his conclusions on genetic inheritance. Before he studied plants, Mendel bred mice while in the monastery. He was advised, however, by the local bishop to devote on a more genteel area of study. Hence, he devoted his time to hybridizing ornamental plants instead of animals as his subjects for artificial pollination.
In the first lines of his paper “Versuche über Pflanzen-hybriden” or the “Investigations on Plant Hybrids,” he wrote that his experience on artificial fertilization of ornamental plants led to valuable lessons that he later applied to his experiments with the common garden pea. One of the ornamental plants used was the Sedum plant, a flowering shrub noted for its attractive colors. This flower was artificially pollinated to obtain new variations in color. He also observed other traits of the plant, such as the form and size of leaves as well as the pubescence of the other plant parts.
Mendel found that there is a striking regularity with which the same hybrid forms during the fertilization of the same species. Furthermore, there are cases when one of the two parental characters is so dominant that it is hard to detect the other parental character in the hybrid. From these observations, the experiments with Sedum plants showed that the produced hybrids are not exactly intermediate between the parent species. These observations were all noted before his famous experiment that led to the development of two important laws in the field of genetics.
With all the observations from ornamental plants, Mendel contemplated on the best choice for his study to be scaled to a larger experiment. Many factors, taking into consideration all the lessons he learned from past experiments, led him to choose the common garden peas.
Of all flowering plants in his monastery, why did he choose to study the common garden peas? The shape of the flowers of the Leguminosae family was something special for Mendel. With its enclosed shape, the flowers are easily protected from foreign pollen. Mendel knew how hard it can be to exclude other external factors when cross-pollinating flowers with different traits. Again, he learned his lessons well from the Sedum flowers.
From the many plants from this family, he finally chose the common garden pea or Pisum sativum with its ideal characteristics for his experiment. It was also practical to conduct the experiments because the pea plants can be cheaply cultivated in large numbers in a relatively small space and can quickly produce offspring. Furthermore, its reproduction can be well manipulated due to its flower’s special structure.
In ending, the success of the concept of genetics was not based on pure luck. It was a product of years of hard work and thorough observations. The preliminary studies of the Mendelian genetics of Sedum plants, together with other ornamental plants, might not be as popular as the experiment with the peas but these led the way to Gregor Mendel’s more important works.
Corcos, A. F. & Monaghan F. V., Gregor Mendel’s Experiments on Plant Hybrids: A Guided Study, 1993