Shade, Establishment Method, and Varietal Effects on Rhizome Yield and Curcumin Content in Turmeric in Alabama

Abstract

ABSTRACTGrowing interest in curcumin from turmeric (Curcuma longa L.) for medical and health purposes has led to interest in turmeric cultivation in the United States. The warm growing season in Alabama is short relative to tropical environments where the plant is normally grown, and research on cultural practices is lacking. A split‐split‐plot experiment was performed in Alabama to assess the effects of shade (40% shade vs. no shade), establishment method (early establishment in greenhouse over heat vs. direct seeding), and variety on rhizome yield and curcumin content. Canonical discriminant analysis revealed distinctive trends based on varietal differences, establishment methods, and presence or absence of shade. Extending the growing season by early establishment in the greenhouse increased rhizome and curcumin yield, as well as curcumin concentration in lateral rhizomes. Shade increased plant height, leaf size, and fresh weight of rhizomes, but an apparent increase in rhizome dry weight was not significant. Shade decreased curcumin concentration and yield in mother rhizomes but had little effect on curcumin concentration in lateral rhizomes. An apparent increase in curcumin yield in lateral rhizomes with shade was not significant. Significant differences among varieties were observed for rhizome yield and curcumin concentration and yield. Cultivation of turmeric in Alabama is feasible by extending the growing season and selection of short‐season varieties high in curcumin.