Plant Breeding

Another seed character whose selection was favored long ago was the ability to germinate soon after planting. In cases where seed dormancy was imposed by thick, impermeable seed-coats, a selected reduction in seed-coat thickness allowed more prompt germination. Wild or semi-domesticated peas, found as carbonized remains in archeological sites throughout the Middle East, possessed thick seed-coats with a characteristic, gritty surface texture. Similarly, the seed-coats of Cicer reticulatum from Turkey, the immediate progenitor of the chick pea, account for about one-quarter of the total material in the seed. However, modern cultivars of the chick pea (Cicer arietinum) commit only 4-9% of the seed weight to seed-coats. The seed-coats are thinner because there are fewer cells in the outermost sclereid layers. Cultivated chick peas also lack the brown and green pigments typical of wild-type seeds.

Seed dormancy imposed by natural growth regulators was also selected against in prehistoric times. For example, cultivated oats (Avena sativa) lack the dormancy mechanisms of wild oats (Avena fatua), and germinate soon after seasonal planting.