Undergraduate Poster Competition 2023

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  • Poster

    Screening Commercial Resistance to Adapted Soybean Cyst Nematode

    (2023-01-08) Johnson, Conner

    MSoybean cyst nematode (SCN) is the leading cause of yield loss for soybeans in North America, causing an estimated loss of 566.5 million bushels between 2015 and 2019. While the situation was much improved for a few decades after the introduction of resistant cultivars, things have gotten worse over the past 15 years, as the resistant varieties that once held back this disease have become less and less effective.

    Most commercial varieties derive resistance gene from one source, cultivar PI 88788. These resistant varieties have been grown season-after-season throughout most of the soybean-producing regions, putting massive pressure on SCN populations to adapt. In some states, such as Illinois and Iowa, virtually all SCN isolates from the last few years successfully overtake PI 88788 and resistant varieties derived from it. While most of these varieties are labeled resistant to SCN, there is an ongoing need to monitor which available varieties still limit SCN reproduction and soybean yield loss, and how well each does so.

    This study set out to screen 128 commercial soybean cultivars against SCN populations isolated from Ohio fields. Three seedlings of uniform length from each variety were planted into separate cylinders. A baseline was established using the standard SCN-susceptible variety, Lee-74. Plants were inoculated with 1 mL of a 3000 eggs/mL SCN solution. Plants were grown for 30 days in the greenhouse to allow the nematodes to complete one life cycle. After this, plants were pulled out, and the females (or cysts) were extracted from the roots by wet sieving. Females from each were counted under 40x magnification. The number of females on each plant was divided by the number on the known susceptible variety to obtain the female index (FI). Plants were categorized according to Niblack s (2005) standard: a plant with less than 10% as many females as the susceptible is highly resistant, 10%-25% is resistant, 25%-40% is moderately resistant, 40%-60% is low resistance and greater than 60% reproduction is no resistance.

    Of 128 varieties screened against this SCN population, more than 40 were classified as no resistance, 18 as low resistance, and only 10 as highly resistant. This specific isolate is highly virulent to PI 88788, so farmers planting in fields with this pathotype can expect significant yield loss on most commercial soybean varieties. While this pathotype is common in places like Illinois and Missouri, it is fortunately not common in Ohio yet, so these varieties are being screened again with another Ohio SCN population that is less virulent on PI 88788. That data will be available beginning in early January 2023. Overall, this study shows the need for new soybean varieties which incorporate other known resistance genes for SCN. Some varieties with resistance genes from Peking have successfully come to market, but farmers must be able to rotate these with other resistance sources (which have yet to be bred into commercial cultivars) and with non-hosts to prevent SCN populations from adapting as quickly as the population used here did.

  • Poster

    Estimating seafood harvest requirements to support the traditional food system of First Nations in British Columbia

    (2023-01-08) Janacek, Rebecca

    Background: Estimating the subsistence harvest in First Nations is important for developing fishery management strategies. It is common to rely on reported catch values when estimating subsistence harvest, but frequent underreporting and discrepancies between the fish that are caught and those that are consumed can lead to incorrect estimates. Objectives: In this study, we aimed to 1) determine the quantity of Pacific fish harvest required to maintain the traditional diet of six coastal First Nations communities in British Columbia (Kitsumkalum, Hagwilget, Skidegate, Nuxalk, Namgis, and Tla amin), and 2) identify gaps in data availability and highlight suggestions for improved methodology in future studies. Design: We used food frequency questionnaires from the 2011 First Nations Food, Nutrition & Environment Study to determine food use, and the census data from Statistics Canada to determine the population demographics of these communities. We identified 15 culturally important species, including eulachon (Thaleichthys pacificus), Pacific halibut (Hippoglossus stenolepis), sockeye salmon (Oncorhynchus nerka), and chinook salmon (Oncorhynchus tshawytscha) based on their local consumption prevalence. Employing a proportional projection, we estimated the annual consumption rate for each species by sub-population and used conservative edible yield estimates to determine the total catch needed to sustain traditional seafood consumption levels for average and upper consumption frequencies. Results: Harvest requirements varied widely between fish species and the type of projection employed; the species with the highest subsistence harvest was sockeye salmon (Oncorhynchus nerka) at 5822.858 kg/year, equivalent to approximately 1459 3405 fish. For future studies, we suggest working with FNs communities to establish community-specific harvest schedules, and on focusing on harvest-sharing networks and the relationship of FNs living on-reserve and off-reserve to estimate subsistence harvest requirements with more accuracy. Conclusions: The results of this study establish a baseline of traditional seafood consumption in First Nation communities in BC, which can will be useful for fisheries management planning. Keywords: First Nations; food security; subsistence harvest; consumption survey; Indigenous fisheries; Pacific Maritime ecozone; British Columbia; on-reserve and off-reserve