﻿Seed viability of common ragweed (Ambrosia artemisiifolia L.) is affected by seed origin and age, but also by testing method and laboratory

Rea Maria Hall,Ahmet Uludag,Uwe Starfinger,Bojan Konstantinovic,Bernhard Urban,Gerhard Karrer,Annamaria Fenesi,Ulrike Sölter,Johan Van Valkenburg,Suzanne Lommen,Hana Skalova,Lenka Moravcová,Gabriela Kazinczi

doi:10.3897/neobiota.70.66915

Abstract

Common ragweed (Ambrosia artemisiifolia L.) is an annual Asteraceae species native to North America which is highly invasive across Europe and has harmful impacts, especially on human health and agriculture. Besides its wide ecological range, particularly its high reproductive power by seeds is promoting its spread to various habitats and regions. To prevent further spread and to control the plant, the European Commission funded projects and COST-Actions involving scientists from all over Europe. A joint trial was set up comprising eight different laboratories from Europe to study seed viability variation in different seed samples. Three different testing methods (viability test with 2,3,5-triphenyltetrazolium chloride (TTC), a germination test combined with a subsequent TTC test and a crush test) were tested within the EU-COST-Action SMARTER network to four different seed origins. The viability test results from different laboratories were compared for variation amongst tests and laboratories. The main aim was to optimise the reliability of testing procedures, but results revealed not only significant effects of seed origin and seed age on seed viability, but also considerable differences between the output of the individual testing methods and furthermore between laboratories. Due to these significant differences in the results of the testing labs, additionally a second test was set up. Twelve Austrian ragweed populations were used for TTC testing to obtain a precise adjustment of the testing method as well as a tight guideline for interpreting the results, particularly for the TTC state “intermediate” since a proper classification of TTC-intermediate coloured seeds is still a challenge when determining viability rates.

Highlights

Information on seed viability is of significant importance, in agricultural science, and in the field of invasion ecology
Common ragweed (Ambrosia artemisiifolia L.) is an annual Asteraceae species native to North America which is highly invasive across Europe and has harmful impacts, especially on human health and agricul
In all laboratories participating within the joint trial, H1-2014 showed the highest germination rate which accounted for 74.7% on average, followed by the population A2-2013 with a mean of 69.4%

Summary

Introduction

Information on seed viability is of significant importance, in agricultural science, and in the field of invasion ecology. For annual invasive alien species, production and performance of seeds is the main driver of naturalisation (Richardson et al 2000) In this context, seed persistence is often associated with invasion success, since the ability of delaying seed germination through time is a bet-hedging strategy that spreads the risk of reproductive failure. Common ragweed is one of the most important weeds in spring crops like sunflower, soybean, maize, sugar beet and oil seed pumpkin. It colonises other human-disturbed habitats, such as roadsides, construction sites, abandoned gravel pits and riverbanks (Fumanal et al 2008b; Essl et al 2015,). Schaffner et al (2020) even estimated direct and indirect costs caused by common ragweed in the European Union by Euro 7.4 billion per year

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