THE EFFECT OF GIBBERELLIC ACID EXPLANTS OF THE (Solanum tuberosum L.) POTATO GROWTH

The aim is to know the adequate quantity of Gibberelic Acid (GA) in-vitro dissemination at the potato. We selected young healthy seedling Diacol Capiro and Parda Pastusa plant varieties. We extracted the vegetative buds of 7 mm long approximately. We sowed each vegetative bud in a 60 cm(3)-test tube that contained 6 ml. of culture medium, Vitamins, GA3, Sucrose, and Agar; with a pH 5.8. The tubes were placed in the growth-room under constant conditions of 1000 lux per 24-h, and at a temperature 20 +/- 2 degrees C. We used a completely randomized block-design with 9 doses of GA(3) (0, 10, 20, 40, 80, 150, 300, 600, 1200 mg L-1), and two varieties of potato. Each unit corresponded to a vegetative bud, and a total of 72 experimental units. We determined that by adding 20 mg L-1 of GA to the culture medium, we obtained the highest root-length values (1.19 cm. for Parda Pastusa, and 0.028 cm. for Diacol Capiro), the leaf-area (0.402 cm(2) for Parda Pastusa, and 0.028 cm for Diacol Capiro), and the second plant final height. By contrast to these results, the highest concentrations 300, 600, and 1,200 mg L-1 of GA(3) displayed an inhibitory effect over the growth. Thus, we found that the Papa Pastusa and Diacol Capiro varieties have a different behavior at the evaluated variables, even when the GA(3) dose remains the same.