Physiological quality of Tithonia diversifolia (Hemsl.) A. Gray seeds as a function of harvest period and storage conditions

Bruno Portela Brasileiro, Tiago Teixeira Vianna, Paulo Cesar Hilst, Wander Douglas Pereira, Eduardo Pacca Luna Mattar, Denise Cunha Fernandes dos Santos Dias

Abstract: Tithonia diversifolia is a shrub of the Asteraceae family native to Central America and found on all continents. It has multiple functions with emphasis on use in animal feed and as a medicinal plant. It is usually propagated vegetative, with little information on seed propagation. For this reason, the aim of this study was to define the ideal time for harvesting the seeds and to evaluate the quality of the seeds according to time and storage condition. Therefore, achenes were collected on different days after the anthesis (14, 16, 18, 20, 22, 24, 28, 32, 36 and 40 days) of inflorescence. Following harvesting, the following variables were evaluated: seed dry matter mass, germination percentage, germination speed index, germination speed and percentage of full achenes. Moreover, these variables were analyzed as a function of two storage conditions (refrigerated and non-refrigerated environment) and two storage times (6 and 12 months). The ideal harvest period comprised the period from 28 to 36 days after anthesis, in which seeds with germination percentages exceeding 75% and percentage of full achenes of 100% were obtained. The chilled environment provided the highest percentages of seed germination. Moreover, germination speed increased throughout the storage time. The seeds showed a high percentage of germination after 12 months of storage, both in refrigerated and non-refrigerated conditions.

Keywords: Asteraceae; medicinal plant; Mexican sunfl ower; multipurpose shrub; non-conventional forage; seed production

Date published: 2019-12-19