The “false Orobanche” and the height of Nicotiana tabacum L. cv. "Corojo-2006" on the sun on sticks (Original)

Abstract

The disease called "false Orobanche" caused by Nocardia spp., affects tobacco cultivation in the Central and Eastern region of Cuba. In the plantations where this disorder is manifested, due to the marked dwarfism and rickets that it can induce in the plants, the quality and agricultural productivity decrease, production costs increase and economic losses originate. The objective of the work was to determine the effect of the severity of expression of "false Orobanche" on the height of tobacco plants under production conditions. The experiment was carried out in an agricultural area of ​​Santiago de Cuba, with a history of high incidence of the disease and presence of the agent in the soil. The Black tobacco cultivar "Corojo-2006" susceptible to the disease was used. The first qualitative visual scale was developed that describes the levels of intensity of the expression of symptoms induced by the causal agent of "false Orobanche" in tobacco cultivation under production conditions. In increasing order of severity, the symptoms were named: light, medium and intense. It was determined that growing conditions under the sun on sticks, the tobacco plants of the cultivar "Corojo-2006" affected by an "intense" level of severity of expression of symptoms of the "false Orobanche" present a dwarf phenotype, while those that show “medium” and “low” levels grow normally as if they were asymptomatic.