ABSTRACT
Innovations in propagation have profoundly inuenced plant domestication since the beginning of agriculture. Ten to twelve thousand years ago, unintentional selection of self-pollinating species that reproduced true-to-type from seed gave rise to wheat, barley, and other staples. Four or ve thousand years later, the discovery of asexual propagation paved the way for the domestication of heterozygous species such as grape, olive, and g, which rooted easily when, for example, a broken branch was stuck in moist soil. The domestication of more difcult-to-clone pome and stone fruits awaited the relatively recent discovery of grafting. Despite considerable advances in the science and technology of plant propagation since then,
particularly over the last 50 years, grafting still plays an important role in the production of horticultural crops, including fruits, ornamentals, and even some vegetables.
