Effects of Maleic Hydrazide on yield, dry matter content and sprouting in ware potatoes (Solanum tuberosum L. cv. Spunta)

As the available information on Maleic Hydrazide (MH) in Argentina is scarce, the objective of this study was to evaluate the influence of time (HM1 and HM2) and rates (9 and 12 l.ha-1) of foliar applications of MH [potassium salt of 6-hydroxi-3 (2H)-piridazinone 36%, Vendaval MH 36 potassium, Síntesis Química, Argentina], on yield, sprouting, weigth losses and potato tuber quality for fresh consumption. The experiments were carried out during 1995 and 1996 at Villa Dolores, Córdoba (32º S 65º W) in commercial fields of cv. Spunta. In only one of twelve cases HM application reduced tuber yield while in other cases yield was improved or did not differ from the control. Sprouting time under controlled and field conditions was significantly delayed due to HM applications and the same was true for sprout growth. During storage, either in heaps in the field or in a barn, tuber weight losses were significantly higher in non-treated tubers than in the HM-treated ones. Tuber specific gravity and dry matter content were not modified by HM treatments, besides their values were similar to average values obtained for the same cultivar during several years. It is concluded that HM applied at the doses and time used in this work effectively inhibited sprout growth and reduced weight losses without affecting yield and dry matter content of the tubers.

Key words: Maleic Hydrazide, yield, dry matter, sprouting, weight losses.