Abstract Detail

Population Genetics/Genomics

Duque, Josue [1], Lopez, Alexander Joseph [2], Lum, Romy [3], Waselkov, Katherine [4].

Population Genomics of the Native and Invaded California Range of Palmer Amaranth (Amaranthus palmeri).

Palmer amaranth (Amaranthus palmeri S. Watson), a dioecious, wind-pollinated annual native to the Southwestern United States, has become a new and significant challenge in modern weed management over the last three decades, most recently establishing itself in agricultural systems within the Californian Central Valley since 2015. Palmer amaranth’s range expansion potential is well-documented in the Eastern United States, where it went from a relatively unknown plant to a weedy species of major concern over a short period of time (about twenty years). The recent expansion event into Central California warrants an examination of where the new weed infestations fit into the population structure of Palmer amaranth in the Western United States and what difference in population genetic statistics may be exhibited by the new California populations versus those in Palmer amaranth’s native range. To this end, we have conducted population-level sampling from both these regions and generated high-quality variant data to identify genetic variants (single-nucleotide polymorphisms and indels) for population genetic analysis. Preliminary discriminant analysis of principle components (DAPC) and ADMIXTURE analyses with a pilot dataset (n = 24 individuals) appears to show little evidence of structure within these populations. Both methods indicate that based on our data, a scenario with K=2 genetic clusters is most likely. DAPC cluster membership probabilities place only one individual in a second cluster. ADMIXTURE membership probabilities split the dataset down the middle with 12 individuals in either cluster. Overall F_ST calculations between samples from the native range and samples from the invaded California range returns a value of 0.0047. The clustering analysis results seem to indicate weak genetic structure within the sampled individuals, and the low F_ST value may corroborate this. Currently, work is underway to expand our data set to see if these patterns change with a larger sample size encompassing more sampling locations and including more individuals per population. The results of this study will contribute to knowledge about the genetics of new range expansions, as well as help to inform weed management practices in the impacted California agricultural systems.

1 - California State University, Fresno, Biology, 5214 N Maple Ave, Fresno, CA, 93740, USA
2 - California State University Fresno, Biology, 5241 N Maple Ave, Fresno, CA, 93740, USA
3 - California State University, Fresno, 5214 N Maple Ave, Fresno, CA, 93740, United States
4 - California State University, Fresno, Biology Department, M/S SB73, 2555 E. San Ramon Ave., Science 1, Fresno, CA, 93740, United States

Keywords:
Amaranthus palmeri S. Watson
Population Genetics
SNP molecular markers.

Presentation Type: Oral Paper
Session: PGG3, Population Genetics and Genomics III
Location: /
Date: Wednesday, July 21st, 2021
Time: 12:45 PM(EDT)
Number: PGG3002
Abstract ID:646
Candidate for Awards:None