Page 211 - Plant Canada 2024 Proceeding

PLANT CANADA 2024

not very effective. Moreover, repeated applications of copper can have negative impacts for the
environment and human health. This study aimed to evaluate the antibacterial properties of ethanolic
extracts from different forest species (sugar maple, silver maple, white spruce, Canada yew) against P.
syringae. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of
the extracts were first determined in vitro. Some extracts were afterwards tested for their efficacy as seed
treatment against P. syringae in squash and cucumber. The results obtained showed bacteriostatic and
bactericidal activities of the extracts (MICs = 0.39-3.13 mg mL ; MBCs = 12.5-50 mg mL ) and revealed
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the efficacy of sugar maple leaf extracts as seed treatment. Indeed, seed treatment with sugar maple leaf
extracts significantly (p ≤ 0.05) reduced the rate of P. syringae contaminated seeds as compared to the
control. Future work will be undertaken to evaluate the potential of sugar maple leaf extracts to control the
development of angular leaf spot on squash and cucumber plants cultivated in greenhouse.

*[P15] EFFICIENT IN VITRO DOUBLED HAPLOID PRODUCTION IN BRASSICA NAPUS FROM
ISOLATED MICROSPORE CULTURE. Xinlong Dong, Rudolph Fredua-Agyeman, Stephen E. Strelkov
and Sheau-Fang Hwang. Department of Agricultural, Food and Nutritional Sciences, University of Alberta,
Edmonton, AB T6G 2P5, Canada
Correspondence to: xinlong@ualberta.ca

Canola (Brassica napus) is the second most important oilseed crop in the world. Doubled haploid (DH)
technology enables the rapid generation of 100% homozygous lines within only two generations. In this
study, five DH populations were developed from F1 plants derived from crossing clubroot-resistant donors
(♂) with the clubroot susceptible B. napus cv. ‘Westar’ (♀). To do this, 16 to 52 buds were surface-
sterilized in 7% Ca(ClO)2 and rinsed 3× in sterile water. The buds were ground with a mortar and pestle,
filtered through six layers of cheesecloth, and centrifuged to recover the microspores. The isolated
microspores were treated overnight with 50 mg/L colchicine in NLN13 medium to induce chromosome
doubling, and then resuspended in NLN13 medium without colchicine for 28 days in the dark at 30°C.
Embryos with cotyledons and hypocotyls were transferred to solid B5 agar plates containing 2% sucrose
and 0.1mg/L GA3. After 1-2 months of incubation, the mature seedlings were transferred to a potting soil
in the greenhouse. The number of embryos transferred to solid medium for the five populations ranged
from 392 to 13,471. The plantlet (seedlings with large true leaves and good root development)
regeneration rate ranged from 21% to 32%, with the highest being 47%. This DH production protocol was
about 2-3× more efficient than other methods. The developed DH populations will be used to map
genomic regions associated with clubroot resistance in five clubroot-resistant donors from the U of
Alberta Pathology Lab Collection.
Keywords: Double haploid, Embryogenesis, Microspore, Brassica napus, Clubroot

*[P16] REAL-TIME NUTRIENT ASSESSMENT IN ONIONS USING PICKETA-LENS TECHNOLOGY.
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Ifesinachi Nelson Ezeh , Xavier Hébert-Couturier , and Mary Ruth McDonald . Department of Plant
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Agriculture, University of Guelph, Crop Science Building, University of Guelph, 50 Stone Road E. Guelph,
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Ontario, Canada, N1G 2W1; and Picketa Systems Inc., J. Herbert Smith Center, H-225, Head Hall, 17
Dineen Drive, P.O. Box 4400, Fredericton, NB, Canada, E3B 5A3
Correspondence to: iezeh@uoguelph.ca

The fertilizer recommendations for onions grown on high organic matter soils have not been updated for
decades. Cultivars have changed over time as have some production practices, with more applications of
micronutrients and foliar fertilizers. This study provided baseline tissue analysis data to train the new
Picketa-Leaf Evaluated Nutrient System (LENS) technology for the real-time nutrient status of onions. In
2023, 235 onion samples were collected from the field, including a replicated trial with foliar manganese
and additional foliar fertilizers. Each sample was first scanned using the LENS and then sent for tissue
nutrient analysis at SGS Laboratories. In 2024, a controlled environment (CE) trial was conducted on
onions to induce specific nutrient deficiencies. The 2023 field results showed that onions exceeded the
optimum foliar nutrient concentration in almost all cases. The LENS trained on the data had the strongest
associations for potassium, calcium, and nitrogen (N) with R values of 0.74, 0.72, and 0.67, respectively.
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More samples are needed to train the system for these and other nutrients. The CE trial tested the
effects of low (50% of recommended) nitrogen and low (50%) and high (150%) manganese (Mn) levels on

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