Mendel's work was not accepted because during that time DNA had not yet been discovered. Without the discovery of DNA, there was no concrete proof that the processes Mendel described actually happened.Mendel's Crosses

The result is highly inbred, or “true-breeding,” PEA plants. These are plants that always produce offspring that look like the parent. By experimenting with true-breeding pea plants, Mendel avoided the appearance of unexpected traits in offspring that might OCCUR if the plants were not true breeding.When Mendel MEASURED two or more traits (eg, height and color) in an experiment he found that each trait was transmitted independently. For example, tall or short plants can have SMOOTH or wrinkled seeds. This is Mendel's LAW of Independent Assortment (which strictly holds only if the genes are not too close).We turn now to Mendel's analysis of the lines breeding true for flower color. In one of his early experiments, Mendel pollinated a purple-flowered plant with pollen from a white-flowered plant. We call the plants from the pure lines the parental generation (P).