Otero-Arnaiz A., Casas A., Bartolo C., Pérez-Negrón E., Valiente-Banuet A., Evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacán Valley, central Mexico: Reproductive biology, American Journal of Botany, 2003, 90(4):593-602, doi: 10.3732/ajb.90.4.593
Comparison of wild, field-retained and cultivated Polaskia chichipe populations in the Tehuacán Valley covers phenology, flower opening, controlled pollination and seed germination. Some flowers produced fruits after self-pollination, with results varying among management types. Naturally pollinated flowers had high fruit set, while experiments allowing daytime or nighttime access indicated a predominant daytime contribution. Seeds from managed populations germinated faster and in higher proportions under the laboratory conditions used.