Indução de resistência a Colletotrichum sp. em Heliconia psittacorum x sparthocircinata cv. Golden Torch cultivada em ambiente sombreado e pleno sol

ABSTRACT

Among the major diseases that affect the genus Heliconia, anthracnose (Colletotrichum sp.) is highlighted for interfering in the production, development and quality of flowers. As a management alternative, resistance induction using biotic and abiotic inducers has been adopted. Thus, the present study aimed to test resistance inducers on the control of anthracnose in the genotype Heliconia psittacorum x sparthocircinata cv. Golden Torch grown in shade and full-sun environment, as well as to determine the activation of pathogenesis-related enzymes. Two resistance inducers were used together: a biotic inducer, Bacillus subtilis, and an abiotic inducer, Acibenzolar-s-methyl (ASM). Experimental design was in randomized blocks, in a 2x2 factorial arrangement (two cultivation conditions [shade-level screen (50%) and fullsun] x two resistance induction conditions [with and without application of inducers]), including three subdivided plots of 3x3m. Each subplot contained 9 replicates and 2 tillers for assessing the disease severity plus 5 tillers for determining the pathogenesis-related proteins (PRP’s). To assess productivity, an area of 2x2m was determined within each subplot. Samplings for analysis of peroxidase, β-1,3-glucanase and total proteins started 24 hours after the application of inducers and were performed at 24, 48, 72, 96 and 120 hours after treatment. The resistance inducers used together acted as elicitors for the activity of peroxidase and β-1,3 glucanase; in addition, plants grown in the shade environment showed less severity and smaller Area Under the Disease Progress Curve (AUDPC) when compared to plants grown in full sun. In treated subplots, the inducers reduced the disease severity, but there was no interference for AUDPC. The inducers increased the productivity of flower stems, which reached 68.65% in plants grown in shade environment and 26.86% in plants grown in full sun.

Keywords
anthracnose; peroxidase; β-1,3 glucanase; floriculture