Agronomic, Chemical, Physical, and Visual Characteristics of Hand-Suckered vs. Maleic Hydrazide-Treated Flue-Cured and Burley Tobaccos

Removal of the developing inflorescence (topping) in tobacco (Nicotiana tabucum L.) production will result in higher leaf yield and increased alkaloid content. Unfortunately, topping will remove axillary bud (sucker) inhibition. To achieve the higher yields and alkaloid content growers must control the development of suckers through manual or chemical means. Because hand-suckering is a menial task, the use of maleic hydrazide (MH) rapidly became the cultural practice to control sucker growth, but its use was severely questioned by the industry. The Regional Tobacco Growth Regulator Committee was established in 1963 to evaluate tobacco treated with various experimental chemical sucker-controlling agents as alternatives to MH. Regional committee test data accumulated from 1963 through 1981 by federal and state researchers were used to compare cured leaf from MH-treated plants with hand-suckered plants, the control treatments. Yield and value per hectare were higher from the use of MH while dollars per 100 kg were the same for both kinds of treatments in both classes of tobacco. Tobacco leaf experts were able to visually differentiate between MH-treated and hand-suckered flue-cured but not burley tobaccos. Chemical analyses indicated that percent total alkaloids and percent total ash were less in MH-treated flue-cured and burley tobaccos. Alkalinity of water soluble ash increased from MH treatment. Total volatile bases minus nicotine (as ammonia) decreased significantly in flue-cured tobacco from MH treatment while the increase found in burley from MH treatment was not. Maleic hydrazide treatment significantly increased per cent reducing sugars in flue-cured tobacco, but had no effect on percent total N in burley. Physical analyses indicated that values for filling capacity were significantly lower and equilibrium moisture content significantly higher in MH-treated tobaccos.