Estimation and Comparison of Base Temperatures for Germination of European Populations of Velvetleaf (Abutilon theophrasti) and Jimsonweed (Datura stramonium)

Abstract

Weed emergence models require biological parameters such as base temperature for germination, determination of which is costly and time-consuming. Transferability of these parameters across different populations may therefore represent one of the main constraints for the development and practical use of emergence models at a large scale. A collaborative project was undertaken to assess the interpopulation variability of base temperature for germination in different European populations of velvetleaf and jimsonweed and evaluate possible applicative consequences in terms of weed control. Seeds were collected in Italy, Portugal, and Spain, and each population was then sown in every country, obtaining nine seed batches named as experimental lots. Base temperature for germination was estimated for each experimental lot to calculate lot-specific accumulation of growing degree days (GDD) under three dissimilar climatic scenarios. Threshold date (TD50) was calculated as the date when GDD accumulation of a given experimental lot surpassed the values corresponding to 50% of cumulative field emergence of seedlings. GDD accumulation and TD50were then used as indicators to identify differences among experimental lots within each climatic scenario. No significant differences were detected among base temperatures estimated for velvetleaf experimental lots or among their patterns of accumulation of GDD and TD50values within climatic scenarios. Each value of base temperature determined for a single experimental lot could therefore be adopted to model germination for all the lots regardless of the population of origin or cultivation site. In contrast, the population of origin affected the base temperature for jimsonweed, with significantly higher values for experimental lots of the Portuguese population. From an applicative perspective, differences among patterns of accumulation of GDD and TD50of several experimental lots within each climatic scenario suggest the need to use population-specific values as base temperature for germination and emergence modeling of jimsonweed.

Base temperatures for germination of selected weed species in Iran

“…The range of t b values estimated for a. theophrasti (3.5 ± 1.15°C to 4.9 ± 0.16°C) was in complete agreement with the results of previous studies on an Iranian population (Sadeghloo et al 2013), but also on European populations (Masin et al 2010;Loddo et al 2013), while Dorado et al (2009b) reported a value of around 7°C as t b for a Spanish population. Results obtained for a. albus (t b from 10.4 ± 0.42°C to 13.1 ± 0.46°C) confirmed previous findings by Steckel et al (2004), who observed almost no germination for this species at 10°C, while higher values of t b , ranging from 14°C to 17°C, were estimated by Steinmaus et al (2000).…”

“…France vs Iran) could have led to interpopulation variability. For example, lower t b for germination has been reported for populations of D. stramonium and C. canadensis growing in colder climates (Loddo et al 2013;Tozzi et al 2014). The lower values of t b estimated for French populations of a. retroflexus and e. crus-galli (Guillemin et al 2013) could be related to a similar phenomenon.…”

“…Local weed doi: 10.17221/92/2016-PPS populations have been reported to have developed different germination behaviour as an adaptation to local environmental and agronomic conditions , and inter-population differences were detected between t b values of weed species such as Datura stramonium L. and Conyza canadensis L. (Loddo et al 2013;Tozzi et al 2014). Therefore investigating the behaviour of local populations could be an important step when trying to calibrate an existing emergence model to geographical areas other than that of creation.…”

Épocas de florescimento e colheita da nogueira-macadâmia para áreas cafeícolasda regiäo sudeste

“…o índice térmico é usado para a determinação da duração dos diversos subperíodos (CARVALHO et al, 2011), garantindo aos produtores, nas diferentes regiões, o conhecimento das prováveis datas da ocorrência de cada estádio fenológico (ENTELMANN, 2012), auxiliando no planejamento da colheita (RIBEIRO et al, 2010), na racionalização e na otimização das práticas culturais , além da estimativa do rendimento dos cultivos (SOUZA et al, 2011) e da elaboração de modelos (LODDO et al, 2013) meteorológicos (PEZZOPANE et al, 2012). Na literatura, são encontrados vários trabalhos sobre o índice térmico, como a floração da nogueiramacadâmia (SACRAMENTO; PEREIRA, 2003), o ciclo do cultivo do sorgo (AJAYI; OLUFAYO, 2004), como também o período crítico de competição do feijão (STAGNARI, 2011).…”

Light Quality Effect on Corn Growth as Influenced by Weed Species and Nitrogen Rate

“…Velvetleaf has been ranked as one of the most troublesome weeds in the United States (Stoller et al, 1993) and is commonly a competitive annual weed in summer crops globally (Loddo et al, 2013). Although yield loss in corn due to velvetleaf competition can be highly variable (Lindquist et al, 1996), research has suggested that grain yields can be decreased by up to 80% depending on field conditions and velvetleaf density (Lindquist et al, 1998).…”