The seed potatoes (Solanum tuberosum) are considered a key factor to ensure high productivity, quality of the tuber and a good harvest. This study was carried out at the University José Rosário Vellano (UNIFENAS), Alfenas, Minas Gerais state, Brazil, from September 2007 until September 2008 in three distinct and sequential stages. The objective was to study the effect of growth regulators applied on: (1) sprouts detached from seed-potato tubers on minituber yield, (2) sprouting minituber and (3) marketable yield originated from minitubers. Potato sprouts used were detached from seed potatoes tubers (virus free), cultivar Bintje, originated from an experimental import of sprouts from Alaska (USA), with two sizes: large sprouts (average of 25 cm) and small sprouts (average of 13 cm) and growth regulators IBA, GA3, BAP and 2,4D. The experimental design for all experiments was of randomized blocks in a factorial scheme 5x2 with three replications. The number of minitubers produced in the first stage originated from large sprouts varied significantly from 3.1 (GA3) to 7.7 (IBA) and 2.3 (IBA) to 7.9 (control), small prouts, while the weight varied from 7.5 g (GA3) to 10.6 g (IBA), large sprouts and 3.4 g (IBA) to 12.3 g (control), small sprouts. The minitubers did not show significant differences for the time of shooting which occurred within seven to eight days. Marketable production originated from minitubers varied significantly from 12.06 t ha-1 (GA3) to 29.51 t ha-1 (AIB), large sprouts and 22.11 t ha-1 (BAP) to 30.35 t ha-1 (control), small sprout. Sprouts from seed-potato tubers cv Bintje, can be used for seed tuber production and should not be treated with growth regulators. Small sprouts, detached from seed potatoes, cultivar Bintje, without treatment, should be preferred for the production of seed-potato minitubers.
Solanum tuberosum; IBA; BAP; GA3; minituber
