Student Contributions to the Vegetable Program
Below is a collection of articles written by Horticulture students in the Department of Plant Sciences. Many of the papers below were written to fulfill required components of horticulture classes.
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Elsadr, H., and D. Waterer. 2006. Efficacy of Natural Compounds to Suppress Sprouting and Fusarium Dry Rot in Potatoes. PDF
Ramachandran, A., W. Hrycan, J. Bantle and D. Waterer. 2005 Seasonal Changes in Tissue Nitrate Levels in Fall-Planted Spinach (Spinacia oleracea).PDF
Hanny Elsadr1 and Doug Waterer2
1. Project conducted as component of PLSC 461.3 course
ABSTRACT: Controlling sprouting and disease growth during storage of potatoes are critical to the maintenance of quality and profitability. CIPC (chlorpropham) is widely used as a sprout inhibitor for table and processing potatoes in North America but it cannot be used on or in the vicinity of seed potatoes. There are also some concerns regarding consumer safety of CIPC residues. At present, there are few products registered for control of Fusarium dry rot in stored potatoes and the available products have become less effective due to selection for resistant strains of the Fusarium fungus. There is a need for alternative methods for sprouting and disease control in stored potatoes.
A variety of ‘natural’ products including ground dill, ground cloves, clove oil, garlic powder, ground peppermint or peppermint oil were tested for their ability to suppress sprouting and the development of Fusarium sambucinum (dry rot) in non-dormant Norland potatoes. Two purified compounds extracted from plants were also tested (R- (-)-carvone and diallyl disulfide). Sprout suppression was examined on the basis of sprout mass at 14 and 28 days after treatments. Effectiveness against F. sambucinum was tested by measuring the size of dry rot lesions at 14 and 28 days after inoculation. A taste test was also conducted at 14 and 28 days after treatment.
Both purified plant extracts (diallyl disulphide and carvone) completely suppressed sprouting for 14 days of treatment and slowed sprouting over an additional 14 day observation period. Garlic powder, peppermint oil and ground cloves also suppress sprouting. None of the treatments suppressed the development of dry rot – and some treatments appeared to exacerbate this disease problem. Some treatments significantly altered the flavor of the potatoes. The altered flavor was preferred by some individuals and disliked by others.
Adithya Ramachandran1, William Hrycan,
Jackie Bantle and Doug Waterer2
1. Project conducted as component of PLSC 451.3 course
ABSTRACT: Excessive levels of nitrates in spinach (Spinacia oleracea) and other green vegetables pose a potential health risk. This study measured the changes in fresh matter nitrate concentrations in four spinach cultivars in the fall of 2005. Spinach grown in research plots in Saskatoon, SK were sampled from mid-September through to freeze up in mid-November. Nitrate concentrations varied between cultivars and between sample dates. Tissue nitrate levels generally declined over the sampling period. Nitrate levels were elevated within a few hours of a frost event and it took several days of mild weather after the frost before nitrate levels in the tissues returned to normal. The initial spike in nitrate levels following frost reflects damage to the metabolic pathways in the leaves that utilize nitrate – while the slow recovery reflects repair to these pathways. The spike in leaf nitrate levels that occurred following the first frosts in early fall was more pronounced than the response elicited by more severe frost events later in the season. This suggests some degree of acclimation to the low temperature stress. Spinach harvested at mid-day had lower nitrate levels than product harvested in early morning.