Page 127 - PC2019 Program & Proceedings

PLANT CANADA 2019

S39. Challenges of cultivating saffron under cold climate
*
Ayari, M-A. ; L. Lapointe
Université Laval

Saffron (Crocus stivus) is an autumn crocus that produces a highly valued spice. Most of the production
of saffron comes from Iran and the Mediterranean basin. Its cultivation under more northern climates such
as North Eastern Canada and US is quite recent. Much of what we know concerning its cultivation must
thus be revisited. This leads us to test several aspects of crop production such as depth and period of
planting, companionship, weed control, and fertilization. Furthermore, we addressed the issue of soil
temperature during the summer, since high flowering yield requires that the corm be exposed to high soil
temperatures (23 to 27 °C) for at least 50 days. Laying either mulch films or mini-tunnels over the beds
during the summer moderately increased soil temperature at corm depth (20 cm) and strongly reduce the
time of hand weeding. Date of planting (early August to early September) also markedly influence the
rate of emergence and flowering in the autumn. Mineral fertilization at planting stimulated corm
production and improved total corm mass and both nitrogen and magnesium absorption. Despite these
improvements, saffron yield remains variable from year to year and strongly influenced by local
meteorological conditions in autumn. Further essays are required to improve and stabilize saffron yield
under temperate climates.

Mohamed Amine Ayari (mohamed-amine.ayari.2@ulaval.ca)

S40. Does spraying paraquat increase in-field inoculum of Colletotrichum fioriniae in celery
production?
1
2
Reynolds, S. ; L. Droste ; M. Celetti ; M.R. McDonald
1
*1
2
1 University of Guelph; Ontario Ministry of Agriculture, Food and Rural Affairs
The fungal pathogen Colletotrichum fioriniae is the causal agent of celery leaf curl. The pathogen can
survive as an epiphyte and endophyte on asymptomatic weeds and produce secondary conidia. Herbicides
are commonly used to control weeds in celery fields, so it was important to determine if killing these
asymptomatic weeds with herbicides results in sporulation of C. fioriniae. The non-selective herbicide
paraquat was evaluated to determine effects on C. fioriniae sporulation on plant tissue and direct effects
on the growth or sporulation of the fungus in vitro. Two common weed species, redroot pigweed and
lamb’s quarters, were inoculated with C. fioriniae. Two weeks post inoculation, leaves were detached,
surface sterilized, and were either submerged in Gramoxone (500 ppm paraquat) or water and incubated
in high humidity. Six days post treatment, abundant acervuli were only observed on paraquat treated
2
leaves, with over 10,000 conidia per cm of leaf tissue. When C. fioriniae was grown on potato dextrose
agar amended with various concentrations of paraquat (0, 1, 5, 10, 50, 100 ppm), no significant
differences were found for mycelial growth rate or the number of conidia produced. This suggests
paraquat has an indirect effect on C. fioriniae sporulation, possibly through the release of nutrients from
rapid plant cell death. Weed management strategies may need to be revised to reduce the inoculum of C.
fioriniae in celery fields.

Stephen Reynolds (sreyno01@uoguelph.ca)

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