Produção da batata-baroa 'Roxa de Viçosa' em função de tipo de muda e de pré-enraizamento

Objetivou-se caracterizar a partição de massa e a produção de raízes da batata-baroa ‘Roxa de Viçosa’, em função de tipos de mudas e do pré-enraizamento. O experimento foi conduzido a campo, em Viçosa, MG, no período de 09/04/99 a 10/02/2000, no esquema de parcelas subdivididas, delineamento experimental blocos casualizados, com dez tratamentos e cinco repetições. Nas parcelas foram dispostos métodos de plantio (com e sem o pré-enraizamento das mudas) e nas subparcelas tipos de mudas (1- ápice do rebento com ± 2,8 cm de comprimento, com corte em bisel na base; 2- segmento intermediário do rebento, com ± 5,1 cm de comprimento, com cortes em bisel nas extremidades; 3- idem ao tipo 2, com corte adicional longitudinal, na parte côncava, retirando cerca de 1⁄4 do diâmetro da muda; 4- rebento inteiro, com ± 5,9 cm de comprimento, com cortes em bisel na base e longitudinal na parte côncava; 5- idem ao tipo 4, porém sem o corte longitudinal na parte côncava). As mudas pré-enraizadas no viveiro foram transplantadas com 4-5 folhas, aos 52 dias. Avaliou-se a população de plantas e as características de parte aérea (folhas, rebentos e coroa) e subterrânea (raízes tuberosas). Houve efeito de tipo de muda isoladamente apenas para massa fresca e diâmetro de coroa. Mudas pré-enraizadas proporcionaram menor perda de plantas durante o ciclo, todavia as plantas remanescentes foram menos eficientes em produção de biomassa total e na alocação de biomassa para as raízes de reserva, comparadas às plantas sem pré-enraizamento. O método do pré-enraizamento de mudas da batata-baroa deve ser mais investigado para cada clone e condição edafoclimática.The influence of five types of offshoots and two methods of planting on plant growth and production of tuber roots ‘Roxa de Viçosa’ were evaluated in cultivation of fall-summer (04/09/99 to 02/10/00). The experiment was arranged in randomized blocks with split plots, containing ten treatments with five replicates. In the plot it was placed the two methods of planting (with and without pre-rooting of the offshoots) and in the split plots it was placed the five types of offshoots (1. 2.8 cm offshoot with upper tip, with base cut in one inclined angle; 2. intermediate offshoot segment with 5.1 cm in length with base and top cut in two inclined angle; 3. identical to type 2, but with additional cut in the concave portion; 4. uncut offshoot with 5.9 cm in length, inclined cut in the base and longitudinal cut in the concave portion; 5. identical to type 4, but without longitudinal cut in the concave portion). The pre-rooted offshoots were transplanted with 4 to 5 leaves in the main stem, at 52 days. The following characteristics were evaluated: stand, height and diameter of plant canopy, fresh matter of crown and roots per plant and area, length, diameter and commercial yield and splitted roots. There was no effect due to offshoot type used on the yield of roots. Despite fact that higher number of plants remained in the field after transplanting there was not increase the yield/plant and yield/area. Plants from without pre-rooted offshoots had higher values on the total characteristics evaluated, and were more efficient in production of total biomass and in the biomass allocation for to roots, compared to the plants with pre-rooted. The method pre-rooting of the offshoots should be more investigated in each particular environmental condition and clone used