Description:
Several Amaranthus species are very common and are not prohibited noxious weeds (e.g., redroot pigweed, smooth pigweed), and seeds of the various Amaranthus species (Table 1) cannot be reliably visually identified. This invention describes a DNA genotyping method to detect either Palmer amaranth or wathermp in a mixture of bulked Amaranthus seeds.
Investigators at Colorado State University developed a novel assay to identify polymorphisms which identify each of the nine Amaranthus species. Specifically, this assay is used to detect at minimum one Palmer amaranth seed in 50 seeds, as well as identifying waterhemp at the same ratio. Further, this assay detects regions in Amaranthus species which contain sequence polymorphisms that enable the identification of each of nine Amaranthus species (A. palmeri, A. tuberculatus, A. albus, A. spinosus, A. blitoides, A. arenicola, A. hybridus, A. powellii, and A. retroflexus).
Key advantages:
- Identification of Palmer amaranth at a 1 in 50 seed ratio (or better)
- Uses reliable, robust industry standard genotyping methodology
- Assay validated using blind samples
Figure 1 - Palmer amaranth forward primer (FAM) and all other Amaranthus species forward primer (HEX). Palmer amaranth (P) seeds were mixed with waterhemp (W) in ratios of 1:2, 1:4, 1:6, 1:8, 1:10, 1:20, and 1:50. Additionally, controls were run with all palmer or all waterhemp DNA.No template controls (NTC) were included to control for non-specific fluoresence in the assay. The assay appears able to identify 1 Palmer amaranth seed in a mixture of 50 total seeds.
Figure 2. Palmer amaranth forward primer (FAM) and all other Amaranthus species forward primer (HEX). Palmer amaranth (P) seeds were mixed with waterhemp (W) in ratios of 1:2, 1:4, 1:6, 1:8, 1:10, 1:20, and 1:50. Additionally, controls were run with all palmer or all waterhemp DNA.No template controls (NTC) were included to control for non-specific fluoresence in the assay. The assay appears able to identify 1 Palmer amaranth seed in a mixture of 50 total seeds.
