ABSTRACT: Cadmium (Cd) is a heavy metal that is extremely dangerous to human health and can be found naturally in soils, deposited through industrial waste or phosphate fertilization. In this study, we evaluated the morphological responses of in vitro grown plants of potato in the presence of Cd, and define a procedure for assessing Cd sensitivity of different clones. The potato clone SMIJ461-1 was cultured in the presence of Cd at concentrations of 0, 20, 40, 60, 80, 90, 110, 120, 140, and 160 µM. Survival, rooting, number and height of shoots, leaf and root counts were evaluated at 7, 14, 21, and 28 days of cultivation. Adverse effects of Cd on the growth of the potato plants, exerted in a concentration-dependent manner, were observed for shoot height, leaf and root counts. Results of this study indicated that Cd concentrations of 0, 45, 90, and 135 µM can be used for future in vitro evaluation of potato clone sensitivity to Cd exposure.

RESUMO: O cádmio (Cd) é um metal pesado extremamente perigoso à saúde humana, podendo ser encontrado naturalmente nos solos, depositado através de resíduos industriais ou da adubação fosfatada. Este trabalho teve por objetivo avaliar as respostas morfológicas de plantas de batata cultivadas in vitro na presença de Cd e definir uma metodologia para inferir sobre a sensibilidade de diferentes clones. Foi estudado o clone SMIJ461-1 de batata, nas concentrações de 0, 20, 40, 60, 80, 90, 110, 120, 140, 160 µM de Cd adicionadas ao meio de cultura. A sobrevivência, o enraizamento, o número de brotações, a altura da parte aérea e o número de folhas e raízes foram avaliados aos 7, 14, 21 e 28 dias de cultivo. Foram observados efeitos adversos de concentrações de Cd sobre o crescimento in vitro das plantas de batata do clone SMIJ461-1 para a altura da parte aérea e o número de folhas e raízes, sendo estes efeitos dependentes das concentrações de Cd adicionadas ao meio de cultura. Os resultados deste estudo indicam que as concentrações de 0, 45, 90 e 135 µM de Cd podem ser utilizadas para a avaliação in vitro da sensibilidade de clones de batata a presença de Cd.

Abstract: This study aimed to evaluate half-sibling progenies for developing breeding strategies and to select mate clones with adventitious root competence, required for vegetative propagation by mini-cuttings. For rooting, single-bud mini-cuttings of 2 cm length were treated with indolebutyric acid at 2000 mg L-1. At 60 days of cultivation, the mini-cuttings were evaluated for percentages of survival and rooting, number and mean length of the three largest roots, and number of rooted mini-cuttings per mini-stump. These data were analyzed considering the mixed model described for a completely randomized design, an environment, half-sibling progenies, and a single plant per plot, by using the SELEGEN-REML/BLUP software. The 50 genotypes with the highest number of rooted mini-cuttings were selected. The genetic gain was 48.41% for the number of rooted mini-cuttings per mini-stump. Selection for adventitious rooting based on the number of rooted mini-cuttings can be used in mate breeding programs for vegetative propagation by mini-cuttings.