Technical scientific bases for gamic seed production, sowing and establishment of Tithonia diversifolia (Hemsl.) A. Gray in Cuba

Abstract

Introduction: gamic seed production and set up of Tithonia diversifolia is an unsolved problem for science and there are several unknowns to achieve a feasible technology that integrates these processes in a multidisciplinary way.

Methods: research to evaluate gamic seed production and establishment were carried out at the Institute of Animal Science, Mayabeque, Cuba. The predominant climate of the area is tropical humid (1200 mm per year) and it is located on a eutric red ferralitic soil. All the field experiments included conventional soil preparation, consisting of plowing and crossing with alternating middle harrows. Research on seed production was carried out based on knowledge of the morphological and phenological development of the flower as an indicator of the process of formation and physiological maturation of seeds (achenes). Germination performance was evaluated in laboratory and controlled conditions in the field. Germination percentage was evaluated as indicated by the ISTA standard.

Results: These are the first reports in Cuba about the characterization of inflorescences, as well as the evaluation of different methods to increase germination and their implementation in different types of substrates and conditions (laboratory and nursery). The non-existence of dormancy was defined, achieving germinations of 84% at 10 d and it was ratified not to extend the germination tests for more than 21 d. Seeds stored in the environment lose germination after a year but it last up to 2 years in a cold room. Conservation can be done in plastic containers and paper and nylon bags. For the first time, the moment in which the inflorescences have seeds formed with germinating power is defined. A novel contribution was the definition of a practical scientific method to determine the best moment for harvesting with yields of 24 kg ha^-1 of pure germinable seed and 50 to 90 % of germination. The integral agronomic management allowed to propose practices that cause the appearance of uniform flows of flowering and the use of vegetable and organic residues in seed protection. The advantages of the use of gamic seed, in relation to the planting in bags and stakes, are demonstrated according to the populations (10.55 vs. 10.88 and 5.88 stems m^-2, respectively and the yields 11.68 vs. 9.48 and 9.92 t DM ha^-1, respectively) obtained, in the establishment. Sowing costs can be reduced up to 3 times with gamic seed. The cost of the kg of seed is 273.76 CUP.