Degree Name

Master of Science (MS)

Semester of Degree Completion

1991

Thesis Director

Janice Coons

Abstract

Supersweet types of sweet corn (Zea mays L. var rugosa) are sensitive to low temperature during emergence and thus have difficulty in establishing stands in early spring. This study investigated how banded potash affected establishment of five supersweet cultivars of sweet corn in fields and growth chambers.

In the field, sweet corn cultivars were planted near Urbana, Il on April 18 and July 22, 1991 with three levels of potash (0, 45 and 90 kg/ha) banded at planting. Several parameters of growth and development were measured approximately 2, 4 and 6 weeks after planting. No significant effect of potash was found for either planting date or any sampling times except for chlorophyll b during the warm planting at 15 days after planting. Significant cultivar differences were found for several parameters including number of plants emerged, number of leaves, height, fresh weight, dry weight, leaf area, and total chlorophyll at all sampling dates. 'Crisp'n'Sweet', 'Illini Gold' and 'Florida Staysweet' were more tolerant to low temperature than 'Honey'n'Pearl and 'How Sweet It Is'. Soluble solids varied very little at either planting date. Significant interactions between cultivars and potash were observed only for number of plants emerged, number of leaves, height and total chlorophyll at the warmer planting date.

In growth chambers, plants were grown at 15 or 25°c for 15 days with 0, 5 or 10 g potash per tray (6 x 22 x 30 cm). Significant potash effects were found for chlorophyll a at 15°C and in fresh weight, number of leaves and leaf area at 25°C. Most cultivars showed increased dry weights, number of leaves, number of plants emerged, heights and leaf areas with 5 g potash as compared to 0 or 10 g although 'How Sweet It Is' showed increased chlorophyll concentration at 10 g potash than at 0 or 5g. Significant cultivar differences occurred, with 'Crisp'n'Sweet, 'Illini Gold' and 'Florida Staysweet' being more tolerant than 'Honey'n'Pearl' and 'How Sweet It Is'. No significant interactions between potash and cultivars were found for either both temperature or either run.

Intermediate potash levels in potassium poor soils may improve stands and development of supersweet corn cultivars.

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