Promiscuity in weedy amaranths: High frequency of female tall waterhemp (Amaranthus tuberculatus) × smooth pigweed (A. hybridus) hybridization under field conditions

Federico Trucco, Mark R. Jeschke, A. Lane Rayburn, Patrick J. Tranel

Research output: Contribution to journalArticlepeer-review

Abstract

Several populations of different Amaranthus species have been reported resistant to single or multiple herbicides. Interspecific hybridization among amaranths is hypothesized to contribute to the evolution of herbicide resistance. Although other studies have shown the occurrence of interspecific Amaranthus hybrids, little has been done to establish the likelihood of hybridization under field conditions. The main objective of this study was to determine potential field frequencies of hybridization between tall waterhemp females and smooth pigweed. Field hybridization plots were established during each of two growing seasons. Individuals of the two species were transplanted to field plots and arranged at varying distances from each other. Hybrid progeny were detected using the acetolactate synthase (ALS) gene as a marker. Smooth pigweed parents were homozygous for a herbicide-resistance ALS allele, whereas maternal tall waterhemps were homozygous for a herbicide-sensitive ALS form. Heterozygous interspecific progeny were thus detected by means of herbicide selection. Molecular and cytogenetic tools were used to verify the validity of the data obtained. Averaged among female waterhemp plants and across the two field seasons, hybridization occurred at a frequency of 33%. A single tall waterhemp plant was capable of producing more than 200,000 hybrids, suggesting little if any gametic incompatibility. All flowering hybrids obtained from tall waterhemp females were of dioecious condition and female sex. Observed sexual segregation was consistent with previously postulated chromosomal XY-type system in tall waterhemp sex determination, where males are the heterogametic sex.

Original languageEnglish (US)
Pages (from-to)46-54
Number of pages9
JournalWeed Science
Volume53
Issue number1
DOIs
StatePublished - Jan 1 2005

Keywords

  • Amaranthus rudis
  • Evolution
  • Gene flow
  • Herbicide resistance
  • Introgression
  • Sex determination

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Plant Science

Fingerprint

Dive into the research topics of 'Promiscuity in weedy amaranths: High frequency of female tall waterhemp (Amaranthus tuberculatus) × smooth pigweed (A. hybridus) hybridization under field conditions'. Together they form a unique fingerprint.

Cite this