Final answer:
The Latin term 'filial' used by Gregor Mendel refers to 'daughter or son,' indicating the F1 generation as the offspring of the P (parental) generation in his genetic experiments.
Step-by-step explanation:
The term 'filial' used by Gregor Mendel in his genetic studies comes from the Latin term for 'daughter or son.' When Mendel conducted his experiments on pea plants, he started with the P (parental) generation, which consisted of true-breeding plants. He then cross-pollinated these plants to produce the F1 (first filial) generation. These F1 plants were the direct offspring or 'children' of the original parents. Mendel called them 'filial' to denote their relationship as the offspring of the P generation. He continued his experiments by allowing the F1 generation to self-pollinate to create the F2 (second filial) generation and further observed the inheritance of traits.