The ability of induction and elongation in vitro, rooting, acclimation, and chromosome stability of seedlings from ten varieties of Physalis ixocarpa Brot. was studied. A genotype effect was found at the four micropropagation stages, shoot induction, proportion of explants with shoots varied from 0 to 70 %, the number of shoots per explant was 0 to 21.3, and the best varieties were 'Tamazula', 'CHF1-Chapingo' and 'Rendidora'. During elongation, shoots presented heights from 2.5 to 3.7 cm, 4 to 5 leaves, 104 to 160 mg of fresh weight, and 94.7 to 96.1 % of moisture content; varieties CHF1-Chapingo, Milpero and Arandas had the best response. For rooting, soots produces from 26.6 to 65.6 roots with length from 0.7 to 1.5 cm, were 'Manzano' and 'Puebla' were the best varieties. The critical acclimation period for the seedlings consisted of the first seven days after transplant, but a 100 % survival was accomplished. All in vitro regenerated plants were 2n=24, indicating chromosome stability during in vitro cultivation.
Keywords: Physalis ixocarpa Brot., tomatillo, shoot induction, elongation, rooting, genotype, chromosomes.