ABSTRACT. Improvements in the traditional production system of peach seedlings, with a focus on the use of selected rootstocks, tend to minimize some of the problems experienced with this crop in the south of Brazil, such as the scarcity of vigorous nursery plants and the lack of a genetic identity for commercial rootstocks. The aim of this study was to investigate the different patterns of nutrient absorption and allocation related to the rootstock in ‘BRS Rubimel’ peach plants by analyzing growth variables during the post-graft period. The experimental design consisted of randomized blocks in a 3 × 3 factorial scheme, with three peach rootstock varieties (i.e., ‘Flordaguard’, ‘Capdeboscq’, and ‘Okinawa Roxo’) and three post-graft evaluation periods (i.e., 30, 60, and 90 days after the start of budding), corresponding to a total of nine treatments, with three replications, each including five plants. During the three evaluation periods, morphological growth characteristics were measured, and the macronutrient content was determined in the different plant organs (i.e., leaf, stem, and roots). The nutrient content in plants of the ‘BRS Rubimel’ peach plants was influenced by the rootstock. Despite showing greater N use efficiency, ‘Capdeboscq’ accumulated a large part of this nutrient in the roots, using it for root growth, which resulted in a smaller scion diameter compared to that of ‘Flordaguard’. Comparing the three rootstocks and the evaluated variables, it seems that ‘Flordaguard’ can be used as a rootstock for the ‘BRS Rubimel’ peach plants, as it induces a greater scion diameter as well as the uniform allocation of dry matter between organs during the post-graft period, hence ensuring greater initial plant vigor.

Abstract The aim of this study was to evaluate the initial growth of Agonandra brasiliensis Miers ex Benth. & Hook. F. in response to different levels of shading and doses of controlled-release fertiliser (CRF). The experiment was conducted at Embrapa Roraima in Boa Vista, in a completely randomised experimental design and a 2 x 5 factorial scheme, of two luminosity levels (50 and 30%) and five doses of CRF (formulation 18-05-09, NPK) (0, 0.5, 1, 2 and 3 g L-1 substrate), with five replications, each consisting of five plants. At 240 days after transplanting, the growth characteristics were evaluated, and the influence of the light levels and the CRF dose was recorded on these characteristics, either individually or interactively. It is suggested that plants of Agonandra brasiliensis be fertilised with a dose of 2 g L-1 CRF and grown in an environment with 50% of luminosity to maximize growth and efficiency in the production of high-quality seedlings.

Resumo O objetivo deste trabalho foi avaliar o efeito do raleio químico com metamitron em frutos de pessegueiro (Prunus persica) das cultivares Maciel e Sensação, bem como a sua relação com o teor de carboidratos nos seus ramos. O delineamento experimental foi de blocos ao acaso, e os tratamentos foram plantas sem raleio, raleio manual de frutos e raleio químico com 200 mg L-1de metamitron aos 20, 40 e 60 dias após a plena floração. As variáveis analisadas foram: percentagem de abscisão, produção por planta, número de frutos, presença de lignina nos frutos e teores de carboidratos nos ramos. O teor de carboidratos foi avaliado em plantas com e sem raleio químico, sete dias após a aplicação do produto. O uso de metamitron promove raleamento dos frutos dos pessegueiros ‘Maciel’ e 'Sensação', com redução no conteúdo de carboidratos nos seus ramos. A aplicação de metamitron aos 20 e 40 dias após a plena floração favorece a abscisão dos frutos de ambas as cultivares estudadas.

Abstract The objective of this work was to evaluate the effect of chemical thinning with metamitron on fruit of the Maciel and Sensação peach (Prunus persica) tree cultivars, as well as to identify its relation to the carbohydrate content in their branches. The experimental design was randomized complete blocks, and the treatments were trees with no thinning, manual fruit thinning, and chemical thinning with 200 mg L-1 metamitron applied at 20, 40, and 60 days after full blooming. The evaluated variables were: abscission percentage, yield per plant, number of fruit, presence of lignin in fruit, and carbohydrate content in the branches. The carbohydrate content was evaluated in trees with and without chemical thinning seven days after the application of the product. The use of metamitron promotes fruit thinning in the ‘Maciel’ and ‘Sensação’ peach trees, with a decrease in the carbohydrate content in their branches. Metamitron application 20 and 40 days after full blooming favors fruit abscission in both studied cultivars.

ABSTRACT Mimosa scabrella Bentham (bracatinga) is a prominent forest species in the south of the country, due mainly to the high rate of increase, rapid development cycle, and to enable multiple uses of wood production, both for firewood and for more noble purposes. The aim of this work was to estimate the physiological variation among 40 mother trees, based on germinative and biometric characterization of seeds and seedlings. Biometric traits were determined for the size and the fresh mass of 100 seeds, percentage of germination and normal seedlings, germination velocity index, daily mean germination, length, and dry mass of seedlings. Means were compared by the Scott-Knott test at 1% probability and estimates of Pearson correlation coefficients were obtained between all traits. The results indicate the existence of significant variation between arrays of same or different origin for both the biometric features as those from the germination test. The physiological quality of the seeds showed no direct relation to its size.