Agronomic Practices Affecting Nicotine Concentration in Flue‐Cured Tobacco: A Review

Abstract

Proposed regulations mandating lower nicotine concentrations in tobacco (Nicotiana tabacum L.) products will likely require changes in tobacco production to reduce nicotine while maintaining yield and quality. The agronomic practices used for tobacco production have a significant impact on the synthesis and accumulation of nicotine in flue‐cured tobacco. Nicotine is the primary alkaloid in flue‐cured tobacco and is one of the main reasons for its commercial production. Most agronomic practices that improve plant health and yield have a positive effect on nicotine production and accumulation. Some of the most important factors that affect nicotine concentrations are N fertilization, planting density, topping practices, sucker control, and harvesting practices. The amount of N available to the plant has a substantial effect on nicotine, as N is a primary component of the nicotine molecule. Factors leading to higher N uptake lead to higher nicotine concentrations. Plant and leaf densities within the field also have a significant effect on nicotine, where increasing densities leads to lower nicotine concentrations. Flowering and sucker production are both significant sinks of energy and other resources. Eliminating the inflorescence via topping and controlling suckers lead to higher nicotine concentrations. In fact, substantial nicotine synthesis and accumulation occurs in the days and weeks following topping. This comprehensive review discusses the agronomic factors affecting alkaloid production in flue‐cured tobacco, and how these factors can be adjusted to manipulate the ultimate nicotine concentration.Core Ideas Proposed regulations may require lower tobacco nicotine concentrations. Production practices and timing significantly influence nicotine and leaf quality. Nitrogen fertility, crop density, growth regulation, and harvesting are paramount. Low density, high N, and increased maturity enhance nicotine accumulation. Flowers and axillary shoots are sinks that limit foliar nicotine concentrations.