GREENNESS INDEX OF LISIANTHUS (Eustoma grandiflorum (Raf.) Shinners) AS A FUNCTION OF 6-BENZYLAMINOPURINE CONCENTRATION

Abstract

The management of foliage color is of great importance in ornamental species. This study evaluated in pre-harvest lisianthus (Eustoma grandiflorum (Raf.) Shinners) the greenness index in the lower, middle and upper strata of the plant, number of buds per flowering stem, stem diameter, plant height, leaf area and biomass in response to leaf spraying of 0.5, 1.0 and 1.5 mM of 6- benzylaminopurine (BAP). Data were compared to two controls, one based on amino acids and one with no treatment, and at post-harvest, the greenness index (SPAD units), petal color and vase life in response to 6-benzylaminopurine supplied in irrigation water and leaf spraying. During 2014 and 2015, in Toluca, Mexico, two experiments were carried out. The experimental design in pre-harvest was completely randomized with five replications and five treatments: 0.5, 1 and 1.5 mM BAP, one control with amino acids (2 mL L^-1) and one absolute control. For the post-harvest phase, a factorial arrangement (2 × 3) under a randomized complete blocks design with three replications was used, where the study factors were the types of application (irrigation water and foliage) and BAP doses (1, 3 and 5 mM). Data were analyzed with analysis of variance and the means of treatments were compared with the Tukey (0.05) test. In pre-harvest, application of amino acids at 2 mL L^-1 produced the maximum greenness index at 69.92 SPAD units, exceeding the control by 16.65 %. In post-harvest, application of 1 mM BAP maintained the greenness index constant across samplings. Petal color was higher with 3 mM BAP sprayed on the foliage (b* = 23.37), which corresponds to intense purple, and the flower vase life for this treatment was 15 d, significantly exceeding the control.