Linda Kull

Degree Name

Master of Science (MS)

Semester of Degree Completion

1992

Thesis Director

Janice Coons

Abstract

Supersweet types of sweet corn (Zea mays L. var rugosa) with shrunken-2 endosperm are preferred by consumers because of their extra sweetness and postharvest retention of good flavor. However, their acceptance by growers is hindered due to reduced field emergence, especially in cold soils. This reduced emergence is related to seed quality. To examine differences between supersweet corn cultivars which are tolerant and sensitive to low temperatures, two cultivars were chosen based on their emergence in the field at low temperatures (10-15 C). 'Illini Gold' was chosen as the tolerant cultivar and 'Honey'n'Pearl' as the sensitive cultivar. Seeds of both cultivars were germinated at 10, 15, and 20 C. Germination percentages and days to 25% germination were calculated. Seed leachate was analyzed for electrical conductivity, potassium, calcium, sugars, and amino acids.

At all temperatures germination percentages were higher for 'Illini Gold' than for 'Honey'n'Pearl. Germination percentages were higher at 15 and 20 C than at 10 C for both cultivars. Days to 25% germination was lower for 'Illini Gold' than for 'Honey'n'Pearl'. Percent ion leakage was 2.2 times higher for 'Honey'n'Pearl' than for 'Illini Gold' and higher at 20 C than at 10 C. At all temperatures, potassium, sugars, and amino acids in seed leachate were higher for 'Honey'n'Pearl' than for 'Illini Gold' and paralleled electrical conductivity. Imbibitional temperature effects were not significant for leakage of sugars and amino acids, and significant for potassium leakage. Calcium in seed leachate was less than 0.001 mg/seed/ml.

Imbibitional leakage of ions, potassium, sugars, and amino acids were more dependent upon cultivar differences than germination temperatures.

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