GRADUATE ORAL PRESENTATIONS AGRO- SCIENCES Aragonite Saturation as an Indicator for Oyster Habitat Health in Delaware Inland Bays Ms. Tahera Attarwala, Amin Boukari, Memory Nakazwe, Jackie Maina, and Gulnihal Ozbay, Ph.D Department of Agriculture and Natural Resources, Delaware State University Oyster farming in Delaware is a crucial industry, bringing in $300,000 to $500,000 in sales every year. Oysters use calcium carbonate ions in the form of aragonite and calcite to form their shells. Ocean acidification can lead to a decrease in carbonate ions making forming these shells difficult. When aragonite saturation state falls below 1, it is considered undersaturated and may cause calcifying organisms to become stressed and their shells to dissolve. Therefore, measuring the aragonite saturation state yields crucial insight into the suitability of habitats to support oyster growth. This project aimed to calculate the aragonite saturation state from seven sites within Delaware Inland Bays to determine their feasibility in supporting the establishment of oyster farms and additional reef efforts. Monitoring was conducted biweekly from July to November 2020 and 2021. Temperature, salinity, alkalinity and pH were measured using YSI methods. Using the Seacarb program package in the R programming language, aragonite saturation state was calculated with the water quality parameters: temperature, salinity, alkalinity, and pH as inputs. In 2020, a majority of the aragonite saturation states were undersaturated, with the average values of all sites remaining below a saturation state of 3. The highest registered average aragonite saturation value in 2020 was 1.31 at the Redefer control site and the lowest value was 0.55 from the Bay City control site. These values may impact the suitability of these sites for sustainable oyster farming and reef efforts. The 2021 data will expand on aragonite saturation trends in the Bay. Funder Acknowledgment: USDA NIFA Capacity Building, Grant Award No. 2016-06642
Identifying Plant Structural Variations among Different Germplasm of Strawberry for Potential Resistance to Anthracnose Fruit Rot Mr. Venkata Hemanth Limmada, V. H. Limmada*1, A. R. Vennapusa1, Michael Moore2, K. Melmaiee1. 1 Department of Agriculture and Natural Resources, Delaware State University 2 OSCAR Imaging Facility, Delaware State University Strawberry (Fragaria ? ananassa) is highly profitable specialty crop in the United States and the world's second largest producer. Strawberry fruits are well-known for their color, sweetness, and nutritional value, but their production is threatened by various viruses. Among, the anthracnose fruit rot and root necrosis produced by the fungus Colletotrichum acutatum is a devastating fungal disease in strawberry and causes significant losses to its production. Introducing the anthracnose-resistant strawberry cultivars is an alternative approach for minimizing disease incidence. The study concentrated on discovering anthracnose resistant lines to achieve this goal. In the present research, we have characterized thirty-one strawberry accessions for their morphological attributes, such as leaf trichomes using environmental scanning electron microscopy to identify the resistance factors associated with the number and type of trichomes in the genotypes. Trichomes (leaf appendages) are important constitutive defense mechanisms which acts as a physical barrier against the locomotion and feeding of pests and pathogens. There are two types of trichomes described in strawberry plants, first were unicellular long and thin simple trichomes (non-glandular), located mainly on leaf veins and leaf margins, mostly on the underside of the leaf. The second were multicellular uniseriate glandular trichomes. These trichomes consisted of one basal epidermis cell, several stalk cells, and a single rounded head cell. Glandular trichomes are known to release chemical compounds and are associated with the plant resistance mechanism. Resistance was correlated with the density of trichomes, both glandular and non-glandular, present on the surface of the leaflets of strawberry genotypes. These structural differences were integrated with in vitro leaf-disc assay method and measured disease incidence, chlorophyll content and lipid peroxidation upon fungal infection. The results revealed an intrinsic relationship between the number of trichomes on the cultivar and the disease incidence rate of the anthracnose and physio-biochemical mechanisms. Resistant genotypes, morphological traits and resistant mechanisms that were identified in the present study will provide a promising tool for exploitation of breeding programs aimed at developing anthracnose resistant cultivars and genetic diversity. Funder Acknowledgment: USDA-NIFA
PAGE 68
FIFTH ANNUAL DELAWARE STATE UNIVERSITY RESEARCH DAY | APRIL 13, 2022
