ABSTRACT: Acacia mearnsii De Wild. (Black wattle) is a forest species with great social and economical importance for the southern region of Brazil. This species has multifunctional characteristics, being cultivated to produce tannin, cellulose and energy. This research identified black wattle genotypes with competence for adventitious rooting for mini-cutting propagation. Single-bud mini-cuttings were treated with IBA at a concentration of 2000 mg L-1. After 30 days of cultivation in a humid chamber, the mini-cuttings were evaluated for percentages of survival, rooting, number of roots, average length of the three largest roots, and the number of mini-cuttings rooted per mini-stump. The identification of the best genotypes was performed with the Selegen REML/BLUP software. Selection between and within black wattle progenies can be performed based on the number of rooted mini-cuttings, making it possible to select genotypes with high competence for adventitious rooting while maintaining genetic variability for new selection cycles to develop clones for vegetative propagation by mini-cutting.

RESUMO: Acacia mearnsii De Wild. (Acácia-negra) é uma espécie florestal de grande importância social e econômica para a região sul do Brasil. Essa espécie apresenta características multifuncionais, sendo cultivada para produção de tanino, celulose e energia. Este trabalho teve por objetivo identificar genótipos de acácia-negra com competência ao enraizamento adventício para a propagação por miniestaquia. Miniestacas de gema única foram tratadas com AIB na concentração de 2000 mg L-1. Aos 30 dias de cultivo as miniestacas foram avaliadas quanto às porcentagens de sobrevivência e enraizamento, número e comprimento médio das três maiores raízes e número de miniestacas enraizadas por minicepa. A identificação dos melhores genótipos foi realizada com o auxílio do software Selegen REML/BLUP. A seleção entre e dentro de progênies de acácia-negra pode ser realizada para o número de miniestacas enraizadas, sendo possível selecionar genótipos com alta competência ao enraizamento adventício, mantendo variabilidade genética para novos ciclos de seleção, visando desenvolver clones para a propagação vegetativa por miniestaquia.

Resumo O objetivo deste trabalho foi avaliar a concentração de ácido indolbutírico (AIB), a composição e o volume do substrato, e o tipo de propágulo no enraizamento adventício e na qualidade de mudas de Cordia trichotoma produzidas por miniestaquia. As miniestacas foram avaliadas quanto à percentagem de enraizamento e número e comprimento de raízes aos 30 e 60 dias de cultivo. Já as mudas foram avaliadas quanto à altura da parte aérea e diâmetro do colo aos 30, 60, 90 e 120 dias de cultivo. O índice de qualidade de Dickson, o número de folhas, e a massa fresca e seca da parte aérea e das raízes também foram determinados aos 120 dias de cultivo. Os experimentos foram conduzidos em delineamento inteiramente casualizado, com seis repetições, em casa de vegetação, tendo-se avaliado diferentes concentrações de AIB, composição e volume do substrato, e tipo de propágulo no enraizamento adventício. As mudas de C. trichotoma podem ser produzidas com qualidade e enraizamento adequado a partir de miniestacas de uma ou duas gemas ou de múltiplas gemas (apicais) quando tratadas com 3.000 mg L-1 de AIB e plantadas em tubetes de 110 cm3 contendo igual proporção de substrato comercial e vermiculita.

Abstract The objective of this work was to evaluate the effects of indolebutyric acid (IBA) concentration, substrate composition and volume, and propagule type on the adventitious rooting and quality of Cordia trichotoma plantlets produced by mini-cuttings. Mini-cuttings were evaluated for rooting percentage and root number and length at 30 and 60 days of cultivation. Plantlets were evaluated for shoot height and stem diameter at 30, 60, 90, and 120 days of cultivation. The Dickson quality index, number of leaves, and fresh and dry weights of shoots and roots were also determined at 120 days of cultivation. The experiments were carried out in a completely randomized design, with six replicates, in a greenhouse, evaluating different concentrations of IBA, substrate composition and volume, and propagule type for adventitious rooting. Plantlets of C. trichotoma can be produced with quality and proper rooting from mini-cuttings with one or two buds or multiple buds (apical) when treated with 3,000 mg L-1 IBA and planted in 110 cm3 tubes containing equal proportions of substrate and vermiculite.

Abstract Acacia mearnsii De Wild. is one of the most widely cultivated forest species in Brazil. Despite its importance, studies on breeding strategies for this species are scarce. Therefore, the aim of this study was to evaluate the progeny and develop early selection strategies for A. mearnsii. Individuals of half-sib progenies were classified according to their genotypic value and selected based on their relative performance. The additive effect was only significant for plant height. The best progenies and plants should be selected based on plant height after approximately 60 days of being in nursery and 2 years of field cultivation. This strategy eliminates the worse progenies, discards inferior genotypes in the nursery, eliminates unselected genotypes based on plant height before flowering, and intercrosses only the best plants in field cultivation. This resulted in an annual genetic gain of 3% for plant height and 2% for diameter at breast height.

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.

RESUMO A competência ao enraizamento adventício é essencial para viabilizar o resgate vegetativo de plantas adultas de erva-mate (Ilex paraguariensis St. Hil.). Os objetivos deste trabalho foram avaliar plantas adultas de erva-mate para a competência ao enraizamento adventício e estudar o resgate destas plantas, por estaquia de brotações epicórmicas, induzidas em diferentes posições do tronco. Sete plantas adultas foram avaliadas quanto à porcentagem de sobrevivência e enraizamento das estacas, oriundas de brotações induzidas pelo anelamento do tronco. Duas plantas que apresentaram a maior competência ao enraizamento foram submetidas à poda da parte aérea e ao anelamento da base, para estimular novas brotações epicórmicas e avaliar o efeito da posição de coleta no enraizamento das estacas. O resgate por estaquia, das mesmas plantas, também foi estudado em brotações epicórmicas induzidas pela decepa. As brotações foram seccionadas em estacas de gema única, tratadas ou não com 3.000 mg L-1 de ácido indolbutirico e mantidas em câmara úmida por 60 dias. As estacas foram avaliadas quanto as porcentagens de sobrevivência e enraizamento. Concluiu-se que é possível resgatar plantas adultas de erva-mate por estaquia de brotações epicórmicas induzidas por poda, anelamento ou decepa. Plantas adultas de erva-mate diferem quanto a competência ao enraizamento adventício das estacas e também quanto a posição de coleta das brotações epicórmicas.

ABSTRACT The competence of adult plants of mate (Ilex paraguariensis St. Hil.) to undergo adventitious rooting is essential to their vegetative rescue by cuttings. This study aimed to evaluate the adventitious rooting competence of adult mate plants, and then rescue these plants by making cuttings from epicormic shoots induced in different trunk positions. The percent survival and rooting of cuttings from epicormic shoots induced by girdling in seven adult plants were evaluated. The two stock plants whose cuttings had the highest rooting competence were further pruned and girdled to evaluate the effect of the position of epicormic shoots on their adventitious rooting competence. The potential success of rescuing of the same adult plants was also studied with cuttings of epicormic shoots induced by coppicing. The shoots were sectioned in single-bud cuttings, either treated with 3,000 mg L-1 indolebutyric acid or untreated, and then cultivated in a humid chamber for 60 days, and then the percent survival and rooting of cuttings was evaluated. In conclusion, we found that it is possible to rescue adult mate plants by cuttings from epicormic shoots induced by pruning, girdling, or coppicing. The adventitious rooting competence of cuttings differs among adult mate plants, and depends on the position of the epicormic shoots on the trunk from which epicormic shoots are collected.