Page 205 - PC2019 Program & Proceedings

PLANT CANADA 2019

S195. The effect of urbanization on the evolution of floral traits in the wildflower Linaria vulgaris
*
Longley, A. ; C. Caruso
University of Guelph

Urbanization-induced changes to the biotic environment may cause divergent evolution between urban
and rural plant populations. One such environmental change is decreased pollinator activity, which can
increase competition for visitation from pollinators, resulting in natural selection for more attractive floral
traits. To test whether urbanization could affect floral evolution, we measured natural selection on floral
traits of the wildflower Linaria vulgaris in urban and rural populations. We did not find evidence that
urbanization intensified selection on floral traits: there was significant selection via seeds/fruit on landing
pad width, landing pad length, and inflorescence size in at least one population, but selection did not
differ between urban and rural L. vulgaris populations. However, we did find that mean floral traits
differed between urban and rural populations. Relative to rural populations, plants from urban populations
had 12.3% wider landing pads, 6.4% longer landing pads, and 11.8% longer nectar spurs. This suggests
that urban populations have already evolved more attractive floral traits than rural populations in response
to increased competition for pollination. However, considering the lack of studies looking at the effects of
urbanization on phenotypic evolution, more research is required to determine whether his trend is
consistent along other urban to rural gradients.

Ariana Longley (alongley@uoguelph.ca)

S196. Monitoring airborne ascospores for the management of white mould (Sclerotinia
sclerotiroum) in dry bean across Canada
3
2
Reich, J. ; U. Karerwa ; S. Chatterton ; M. Harding
2
*1
1 University of British Columbia
2 Agriculture and Agri-Food Canada
3 Agriculture and Forestry
White mould, caused by the fungal pathogen Sclerotinia sclerotiroum Lib. (de Bary), is an economically
important disease of dry bean (Phaseolus vulgaris L.) in the Canadian Prairies. Monitoring the daily
aerial ascospore concentrations of S. sclerotiorum could provide better management of the disease. To
determine the best sampling locations for capturing ascospores, nine Burkard 7-day volumetric spore
samplers were placed in three bean fields in southern Alberta in 2018. In addition, air samples were
collected from a potato late blight monitoring network in the same regions. Daily samples were deposited
into 1.5 mL vials, from which DNA was extracted and ascospores were quantified using species-specific
primers in a qPCR assay. Correlations of the ascospores quantified from samplers within the same field
ranged from not significant to moderate (r = 0.35, p < 0.01), suggesting that a single sampler could suffice
for sampling a single field. Disease incidence within the same fields ranged from very low (seasonal
maximum of 3%) to moderate (seasonal maximum of 25%) under similar ascospore loads, which
highlights the importance of management practices in the prevention of white mould. No ascospores were
detected from the potato late blight monitoring stations. This project will continue for the next 3 years and
will be extended to bean fields in ON and MB to develop a prediction model for white mould.

Jonathan Reich (jonathandreich@gmail.com)

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