In this research an in vitro technique was developed for production and propagation of intergeneric hybrids from immature seeds produced by crossing the domestic sunflower Helianthus annuus and the wild species Tithonia rotundifolia (Mill.) S. F. Blake. For embryo rescue in tissue culture the greatest success was obtained with the sequential use of three MurashigeSkoog based media: a) with amino acids and growth regulator BAP for germination, b) without amino acids and with BAP for micropropagation, and c) without vitamins and growth regulator ANA for root development. The amino acids were added as a source of organic nitrogen. From a single seedling a total of 130 healthy plantlets were obtained. Twenty of them were taken for acclimatization, and only one reached an incomplete flowering stage. Therefore, standardizing acclimatization conditions is still required. In particular, it is necessary to establish treatments that allow a clear definition of the specific conditions for the acclimatization of the hybrid, through the test of different substrate mixtures and nutritive solutions under controlled environmental conditions. It is recommended to try the use of retardants and amino acids, as well as modifications in light intensity.
