CIP Slide Training Series: Sprout Cuttings, a Rapid Multiplication Technique for Potatoes

This technique involves several steps, starting with the sprouting of mother tubers. The sprouts may be treated with gibberellic acid to increase sprout growth, and then cut into pieces containing one or more nodes. The sprout cuttings are then rooted in sand, and may be transplanted to the field or a planthouse. Careful selection of tubers is essential, as they should be free of important systemic pathogens and have been previously disinfected. Dormancy should be broken using locally approved methods, and strict sanitary procedures should be followed to prevent the spread of contact viruses and other diseases. Hands and knives should be washed in a strong soap solution or other approved chemicals, and clean clothes should be worn. To encourage strong sprout growth, tubers should be transferred every 7 to 10 days from dark to indirect light. Darkness increases internodal development and growth, while indirect light enhances strong sprouts and short internodal distance. Long sprouts are easier to handle than short sprouts, but generally yield fewer and weaker cuttings. When sprouts are about 3 cm long, an optional step is the removal of the apical growing point with a sharp scalpel or razor blade. This stimulates lateral growth of the nodes and therefore many more cuttings are taken from each tuber. The shoot tip portion of the sprout should be slightly above sand level after the first watering, and apical cuttings of the sprout should be planted apart from the lower cuttings because they root and grow faster. Roots form and the sprout should be ready for transplanting in about 15 days. This rooted sprout cutting is ready to transplant into pots but not to the field. Two days prior to transplanting, spray the plantlets with a foliar fertilizer following manufacturer's directions. Rooted sprout cuttings can be transplanted either to pots in the planthouse or to the field, taking care to ensure adequate but not excessive root-soil contact. After 2 to 3 weeks, when cuttings are established in the field, they are treated as normal potato plants. Early hilling insures that the stolon-producing stem nodes are below soil surface to maximize tuber production. Average yield from rooted sprout cuttings sprouts planted in the field should be about 500 g of normal tubers. Approximately 15 days after cutting, the rooted sprout cuttings may be transplanted to small pots or glasses to use as mother plants for single-node cuttings.