Open pollinated green pigweed ( <i>Amaranthus powellii</i> ) × waterhemp ( <i>A. tuberculatus</i> ) hybrids produced in a greenhouse

Green pigweed or Powell amaranth ( Amaranthus powellii), was crossed with waterhemp ( Amaranthus tuberculatus) by allowing open pollination in a greenhouse. Seeds were collected on green pigweed, grown and tested for the presence of waterhemp specific genetic markers. A total of 18.4% of the progeny were identified as hybrid and grown to maturity. All hybrids were dioecious like waterhemp and had very low fertility, since female flowers aborted and male flowers never opened. The pollen inside the unopened flowers had lower viability (44%) than that of the parents (76%).