Variation and Geographical Distribution of Perisperm Starch in Grain Amaranths (Amaranthus spp.), and the Origin of Waxy Perisperm Type

Abstract

Excluding cereals, grain amaranths are known as the only crop with non-waxy and waxy starch types in seeds. We examined the amylose content stored in the perisperm and starch types; non-waxy, waxy and low-amylose types in 266 accessions of three grain amaranth species i.e. Amaranthus hypochondriacus L., A. cruentus L. and A. caudatus L. from around the world. In the accessions from the New World where these species were domesticated, a wide range of amylose contents and all the starch types were detected. Conversely, very limited variation of this trait was observed in the accessions from Asia and Africa. We concluded that the waxy type originated in the New World before being disseminated into Asia and Africa. However, the selection pressure for the waxy type in the perisperm of grain amaranths in the New World was considered to differ from that acting on cereal crops because of differences in the use and people’s preference for sticky food.