The role of plant growth regulators in potato tuber quality assurance

High quality potato tubers are achieved through good crop management from the seed selected for planting through to the end use. Good management can only take place with effective tools to enable the grower, store keeper, and processor to apply best practice. This paper focuses on the role plant growth regulators play in tuber quality assurance and how the tools Fazor (R) (maleic hydrazide) and Aceto Spud-Nic 50 (TM) (chlorpropham) can be employed to achieve best quality particularly in crops used for processing. Fazor is a well established plant growth regulator (PGR) formulated as a soluble granule containing 600 g maleic hydrazide/kg, used world-wide on a range of crops including root and bulb vegetables, tobacco and grass. Maleic hydrazide was first reported to have plant growth regulating properties by D.L. Schoene and O.L. Hoffmann in 1949. Introduction as an agricultural chemical was by U.S. Rubber Co. (now Chemtura) in 1979. Aceto Spud-Nic 50 based on chlorpropham (CIPC) has been used world-wide for potato sprout control for more than 30 years. Chtorpropham was reported as a herbicide in 1951 by E.D. Witman and W.F. Newton and introduced as a herbicide in the same year. Both maleic hydrazide and chlorpropham have modern registration dossiers with toxicology, environmental, efficacy and residue data that has been used successfully to gain Annex 1 Listing in Europe under directive 91/414. Aceto Spud-Nic 50 is registered for use in Russia by Aceto and marketed and distributed by Chemtura Limited. Fazor has been submitted for registration by Chemtura Limited in Russia, Ukraine and Belarus. Due to the cropping cycle of potatoes, storage is necessary to meet consumer demands and in particular to facilitate the potato processing industry. Mid to Long term storage, up to 10 months is common for processing potatoes and necessary for specific varieties. Fazor is applied in the field through standard hydraulic spray equipment. The active substance, maleic hydrazide, translocates through the plant to the tubers where it inhibits mitotic cell division. With correct timing of application Fazor will assure good tuber development by preventing miss-shapen tubers, secondary growth, and premature sprouting subsequently protecting marketable yield. Fazor will also enable proper tuber curing and provide short term, in-store, sprout control. Spud-Nic 50 is applied in-store through specialized fogging equipment. The active substance, chlorpropham inhibits cell division and will ensure sprout control through Long term storage. The combination of the plant growth regulators Fazor and Spud-Nic 50 provides a complete sprout control and tuber quality assurance programme.