EFFECT OF SPROUT INHIBITORS ON RESPIRATION RATE, HEAT EXCHANGE, SPROUTING AND ETHANOL PRODUCTION IN STORED POTATOES (SOLANUM TUBEROSUM L.) (CHIP STORAGE, NEBRASKA, ROTTING)

The effects of maleic hydrazide (MH) applied at three developmental stages (prebloom, full bloom and post-full bloom) and Fusarex applied after harvest on the yield, quality and storability of five potato cultivars under three types of storage (surface, pit and cold storage) were investigated. MH resulted in higher percentage of US #1 over the control. Best results were obtained when MH was applied at post-full bloom. MH when applied at full bloom or at post-full bloom did not result in a significant reduction in yield or leaf area. MH was effective in reducing the percentage of sprouted and rotted tubers in the three methods of storage. However, Fusarex was only effective in reducing sprouting of cold stored potatoes. The surface storage produced the best chip quality but resulted in high percentage of sprouting. This increase in sprouting percentage was effectively suppressed when MH was used. The pit storage resulted in the highest percent of rotting and respiration rate of the tubers. The five cultivars were not significantly different in percentage of sprouting or rotting in the three methods of storage, but they varied significantly in chip quality, glucose content, respiration rate and ethanol production. The cultivar Norchip, having the lowest percentage of glucose, had a lower respiration rate and the best chip quality, whereas Rhinered had the highest glucose content, higher respiration rate and darkest chip quality. The Ebulliometer Salleron method of measurement of ethanol production gave consistently higher value (11% higher) than the refractometer method. When compared to a standard, the Ebulliometer Salleron method was more accurate, due to the error in the refractometer which is more sensitive to minor change in temperature. However, ethanol production measured by both methods was not affected by the application of MH or method of storage. The five cultivars varied significantly in ethanol production. NE A71.72-1 produced the highest number of gallons per cwt (1.15) or 0.094 L/kg and Rhinered produced the lowest (0.99 gal/cwt or 0.081 L/kg) while Haig, Norchip, and Oceania were intermediate