ABSTRACT The production of strawberry seedlings in a soilless cultivation system can be an alternative for the production of seedlings of high physiological and sanitary quality. The objective of this study was to evaluate the influence of the use of different nutrient solutions in mother plants on the production and quality of strawberry seedlings of the Aromas and Camarosa cultivars. The experiment was carried out in two crop cycles: the first cycle in 2016/2017, where four different nutrient solutions (1; 2; 3 and 4) were used for the nutrition of the parent plants of the cultivars under study and the second in 2017/2018, when the most productive solutions (nutrient solution 3 and 4) based on the results of the first cycle were used, together with the two cultivars. The propagules produced were collected, evaluated and rooted in substrate-filled trays, forming plant plugs, which were evaluated for quality. Nutritional solutions influence the propagative potential of the parent plants more than the physiological quality of the plug plant seedlings produced, when they are formed on substrates that provide nutrients. The nutrient solution 4 is the most recommended for the production of strawberry seedlings of the cultivars Aromas and Camarosa, in a soilless system.

Resumo O objetivo deste trabalho foi avaliar avaliar caracterísicas produtivas de pessegueiros submetidos a distintas doses de adubação potássica e estabelecer o nível crítico deste nutriente no solo e nas folhas de pessegueiro. O experimento foi conduzido nas safras de 2016, 2017 e 2018 em pomar comercial, localizado no município de Morro Redondo, Brasil. Os pessegueiros da cultivar Sensação foram adubados com as doses de 0; 40; 80; 120 e 160 kg ha-1 de K2O, na forma de cloreto de potássio aplicado na superfície do solo. Durante os três anos, foram avaliados a produção por planta, o número de frutos, a massa dos frutos, o diâmetro dos frutos e coletadas amostras de solo e folhas para realização de análise química. A adubação potássica em pomar de pessegueiro eleva os níveis deste nutriente na camada de 0 a 20 cm do solo. A adubação potássica via solo aumentou os teores de K nas folhas de pessegueiros. A produtividade dos pessegueiros responde à aplicação superficial de potássio via solo, mas não altera a massa média dos frutos. Não foi possível estabelecer o nível crítico entre a produtividade relativa e o teor de K no solo. O nível crítico estabelecido entre a produção o teor foliar de K dos pessegueiros foi de 2,84%.

Abstract This study aimed at evaluating production parameters of peach trees subject to different doses of potassium fertilization and at establishing the critical level of this nutrient in the soil and in peach tree leaves. The experiment was conducted in the 2016, 2017 and 2018 seasons in a commercial orchard located in Morro Redondo, Rio Grande do Sul state, Brazil. Peach trees of the cultivar Sensação were fertilized at the following doses: 0, 40, 80, 120 and 160 kg ha-1 K2O as potassium chloride applied to the surface of the soil. In the 3-year study, production per plant, number of fruit, fruit mass and fruit diameter were evaluated while soil and leaf samples were collected to undergo chemical analyses. Potassium fertilization in peach orchards increases levels of this nutrient in the 0-20 cm soil layer. Potassium fertilization via soil increased potassium contents in peach tree leaves. Productivity of peach trees responds to superficial potassium application via soil but it does not affect mean fruit mass. The critical level between relative productivity and potassium content in the soil could not be established while the one between production and potassium content of leaves of peach trees was 2.84%.

Resumen El objetivo de este trabajo es evaluar la concentración de glucósidos cianogénicos CG (amigdalina y prunasina) en el cultivar y portainjerto, como indicador de compatibilidad en injertos de pera. El trabajo consta de dos experimentos. El experimento 1 evaluó las combinaciones Cascatense/Pyrus Calleryana y Cascatense/EMC. El Experimento 2 evaluó las combinaciones Packham’s Triumph/Adams, Santa Maria/Adams y Rocha/Adams. El diseño experimental de los dos experimentos fue de bloques al azar con cuatro repeticiones. Las evaluaciones se realizaron en la primavera y el verano de la cosecha 2014/2015. Los resultados indicaron compatibilidad de injerto en el Cascatense/P. Calleryana; combinaciones de Packham’s Triumph/Adams y Rocha/Adams; leve incompatibilidad de Santa Maria/Adams; e incompatibilidad severa de Cascatense / EMC. Los resultados obtenidos indican que diferencias ≥ 20 mg g-1 de CG entre esqueje y portainjerto se correlacionaron con una drástica reducción del vigor, problemas de continuidad en la unión del injerto, bajo rendimiento y defoliación temprana.

Abstract The objective of this work is to evaluate the concentration of cyanogenic glycosides CGs (amygdalin and prunasin) in the cultivar and rootstock, as an indicator of compatibility in pear grafts. The work consists of two experiments. Experiment 1 evaluated Cascatense/Pyrus Calleryana and Cascatense/EMC combinations. Experiment 2 evaluated the combinations Packham’s Triumph/Adams, Santa Maria/Adams, and Rocha/Adams. The experimental design of the two experiments was randomized blocks with four replications. The evaluations were carried out in the spring and summer of the harvest 2014/2015. The results indicated graft compatibility in the Cascatense/P. Calleryana, Packham’s Triumph/Adams, and Rocha/Adams combinations; slight incompatibility of Santa Maria/Adams, and severe incompatibility of Cascatense/EMC. The obtained results indicate that differences ≥ 20 mg g-1 of CGs between scion and rootstock were correlated with a drastic reduction in vigor, problems of continuity in graft union, low yield, and early defoliation.

Abstract Blackberry is a species which has high potential to grow in an organic production system. However, there is scarce information on the behavior of cultivars and selections of this species conducted in an ecologically based system, a fact that makes it difficult to recommend cultivars for this production system. This study aimed to evaluate and characterize the phenology and productive aspects of six blackberry genotypes grown in an organic system, in Pelotas, Rio Grande do Sul (RS) state, Brazil. Evaluation of the following variables was carried out in the three first production cycles (2015-2016, 2016-2017 and 2017-2018): phenology, number of fruits.plˉ¹, mean fruit yield.plˉ¹, yield (kg.haˉ¹), mean fruit mass (g) and soluble solid content (° Brix). Regarding phenology, genotype Black 112 was later than the others whereas Black 178 was the most precocious one. In the last year under evaluation, genotypes yielded around 10 ton.haˉ¹, except Black 128 selection, which yielded approximately 6,767 ton.haˉ¹. Genotypes Black 178, Black 112 and Black 145 and both cultivars BRS Xingu and Tupy exhibited potential to grow in an organic production system.

Resumo A fertilização orgânica em pomares visa a aumentar a fertilidade do solo e a impactar a produtividade das plantas e a sustentabilidade ambiental. O objetivo deste trabalho foi verificar os efeitos da adubação orgânica e da carga de frutos em duas cultivares de nectarina conduzidas com alta e baixa carga de frutos. O experimento foi realizado em um pomar sob manejo orgânico, em Fratta Terme, no nordeste do vale do Pó, na Itália. Foram utilizadas as cultivares de nectarina Big Top e Carene, implantadas em 2017 e enxertadas em GF677. Três níveis de composto (0; 20 e 40 t ms ha-1) foram combinados com duas cargas de frutas (baixa e alta) para estabelecer um delineamento experimental fatorial com dois fatores e quatro repetições casualizadas. Esse composto foi incorporado a 20 cm de profundidade. Foram avaliados os seguintes parâmetros: concentração de nitrato e amônio-N no solo a 20 - 40 cm de profundidade, macro e de micronutrientes nas folhas, produtividade, número de frutos, massa e diâmetro do fruto, sólidos solúveis e firmeza da polpa. O fornecimento de composto aumentou a liberação de nitrato-N no solo. Em ambas as cultivares, as concentrações de macro e de micronutrientes nas folhas não foram afetadas pela fertilização orgânica ou pela carga de frutos, exceto para o ferro, que aumentou como consequência do fornecimento de composto. A baixa carga de colheita induziu maior tamanho de fruto em ambas as variedades, que foi observado após o endurecimento do caroço. Ao mesmo tempo, a taxa de fertilização orgânica não influenciou a produtividade das árvores, a massa do fruto e os sólidos solúveis.

Abstract Organic fertilization in orchards aims at increasing soil fertility, at impacting plant productivity and environmental sustainability. This study aimed at verifying the effects of organic fertilization and fruit load on two nectarine cultivars with high and low fruit loads. The experiment was carried out in an orchard under organic management in Fratta Terme, Po valley, in northeastern Italy. Nectarine cultivars Big Top and Carene, implemented in 2017 and grafted onto GF677, were used. Three levels of compost (0, 20 and 40 t dw ha-1) were combined with two fruit loads (low and high) to set up a factorial experimental design with two factors and four randomized replicates. Compost was incorporated at 20 cm depth. The following parameters were evaluated: nitrate- and ammonium- N concentrations in soil at 20 - 40 cm depth, macro and micronutrients in leaves, tree yield, number of fruits, fruit mass and diameter, soluble solids and pulp firmness. The supply of compost enhanced nitrate-N release in soil. In both cultivars, macro- and micronutrient concentrations in leaves were not affected by organic fertilization or fruit load, except for iron, which increased as a consequence of the compost supply. Low crop load induced higher fruit size in both varieties, a fact that was observed after pit hardening. However, the organic fertilization rate did not influence tree yield, fruit mass and soluble solids.

Resumo Os porta-enxertos clonais permitem a preservação das características genéticas da plantamatriz, tais como o vigor, e produzem um sistema radicular fasciculado, com abundante quantidade de radicelas. O objetivo do presente trabalho foi determinar o efeito de quinze porta-enxertos clonais na performance agronômica de pessegueiros ‘BRS Kampai’, bem como a viabilidade técnica do uso de plantas autoenraizadas (sem porta-enxerto) em condição de campo sem irrigação, em Pelotas-RS, Brasil. Mudas produzidas em sacos plásticos foram plantadas no campo, em agosto de 2014, sob delineamento de blocos casualizados, com quatro repetições, de uma planta por parcela, e avaliações de diâmetro do tronco, área da secção transversal do tronco, eficiência produtiva, produção de frutos por planta e por hectare anual e acumulada foram realizadas até 2019. Nas condições experimentais adotadas, conclui-se que ‘Barrier’ (P. persica x P. davidiana), ‘Cadaman’ (P. persica x P. davidiana), G x N.9 (P. persica x P. dulcis), ‘Ishtara’ [(P. cerasifera x P. salicina) x (P. cerasifera x P. persica)] e ‘Santa Rosa’ (P. salicina) não apresentam potencial como portaenxerto do pessegueiro ‘BRS Kampai’ devido à irregular quebra de dormência das gemas da copa, frutos pequenos e/ou baixa produção. O Clone 15 (P. mume) destaca-se por aumentar o peso do fruto, mantendo satisfatória produção por planta. O ‘Flordaguard’ (P. persica) é o melhor portaenxerto testado, que é vigoroso, não apresenta nenhuma característica agronômica indesejável e induz as maiores produções por planta e por hectare, superando 50 t ha-1 na produção acumulada. Pessegueiros autoenraizados de ‘BRS-Kampai’ apresentam viabilidade técnica de cultivo, desde que as podas sejam adequadamente realizadas.

Abstract The clonal rootstocks allows preservation of mother tree genetic characteristics, such as vigor and produce a fasciculated root system, with an abundant thin roots. The objective of this research was to determine the effect of fifteen clonal genotypes as rootstocks on the agronomic performance of ‘BRS Kampai’ peach, as well as the technical feasibility of own-rooted trees (without rootstock) in a no-irrigated field condictions, in Pelotas-RS, Brazil. Bagged nursery trees were planted at the field in August, 2014, under a randomized block design with four replications of one tree per plot, and evaluations of trunk diameter, trunk cross-sectional area (TCSA), yield efficiency, annual and accumulated fruit yield per tree and per hectare were carried out until 2019. In the adopted experimental conditions, we conclude that ‘Barrier’ (P. persica x P. davidiana), ‘Cadaman’ (P. persica x P. davidiana), G x N.9 (P. persica x P. dulcis), ‘Ishtara’ [(P. cerasifera x P. salicina) x (P. cerasifera x P. persica)] and ‘Santa Rosa’ (P. salicina) do not have potential as a rootstock of ‘BRS Kampai’ peach due irregular bud breaking of scion, small fruits and/or low fruit yield. Clone 15 (P. mume) stands out for increasing fruit weight and maintaining satisfactory fruit yield per tree. ‘Flordaguard’ (P. persica) is the best rootstock tested, which is vigorous, do not present any undesirable agronomic characteristics and induce the highest yields per tree and per hectare, exceeding 50 t ha-1 in accumulated yield. Own-rooted trees of ‘BRS-Kampai’ peach have technical feasibility, as long as pruning is properly carried out.

Resumo Entre os fatores que afetam a produtividade dos pessegueiros, está a nutrição adequada das plantas, sendo o nitrogênio (N) um dos nutrientes primordiais para a cultura. Deste modo, o objetivo do presente trabalho foi avaliar o efeito da adubação nitrogenada de manutenção nos teores foliares de macronutrientes, no crescimento das plantas e na produção de diferentes genótipos de pessegueiros cultivados em alta densidade de plantio, buscando-se recomendar a concentração mais adequada. O experimento foi conduzido entre 2016 e 2018, com seleções avançadas de pessegueiros ‘Cascata 1513’ e ‘Cascata 1067’, e com concentrações de adubação nitrogenada (0; 60; 120 e 180 kg ha-1 de N). Avaliaram-se: massa de poda, diâmetro de tronco, número de frutos por planta, massa dos frutos, produção por planta e teor de macronutrientes nas folhas. O incremento das concentrações de N aumenta o teor do N nas folhas. Para as condições deste experimento, a máxima produção por planta foi obtida para a maior dose de 180 kg ha de N.

Abstract Among the factors that affect peach productivity is the proper nutrition of plants, being nitrogen (N) one of the main nutrients for the crop. Thus, the objective of the current study was to evaluate the effect of nitrogen fertilization on macronutrient leaf contents, plant development and production of different genotypes of peach trees cultivated at high planting density, seeking to recommend the most appropriate concentration. The experiment was conducted between 2016 and 2018 using peach selections ‘Cascata 1513’ and ‘Cascata 1067’ and with nitrogen fertilization concentrations (0, 60, 120 and 180 kg ha-1 of N). Pruning mass, trunk diameter, number of fruits per plant, average fruit mass, yield per plant, yield per hectare and leaf macronutrients were evaluated. The increase of N concentration increases the N content in leaves. For the conditions of this experiment the maximum production per plant was obtained for the highest dose of 180 Kg ha of N.

Abstract One of the reasons for the low market demand of blackberries in Brazil is the acid taste of the fresh fruit. The fruits of the newly released cultivar BRS Cainguá taste better and have a very attractive shape.

ABSTRACT: Raspberry (Rubus idaeus L.) is an economically important crop and its cultivation has been expanded across temperate and subtropical regions of Brazil. Growing raspberries under plastic cover has becoming more common worldwide. This study investigated the effect of plastic cover on productive and morphological performance of primocane-fruiting raspberry cultivars, in southern Brazil. The experiment was arranged in a 3 × 2 × 2 factorial design, with three raspberry cultivars, ‘Heritage’; ‘Fallgold’ and ‘Alemãzinha’; two cultivation systems, presence and absence of plastic cover; and two production cycles, fall and spring. We measured days from transplanting to flowering and harvesting. Plants were evaluated for dry mass of pruning, plant height, stem diameter, plant leaf area, fruit production, number of fruits, fruit weight, fruit longitudinal and transversal diameter, and harvesting period. Plastic cover reduced incident radiation on the canopy by 17 %. Cultivar ‘Heritage’ is early ripening in the fall cycle. The management under plastic cover prolonged the harvesting period of raspberries in the fall productive cycle for the cultivar ‘Heritage’ and, in spring, for cultivars ‘Alemãzinha’ and ‘Fallgold’. In the spring cycle, plants increased their leaf area, fruit production and number of fruits. The cultivar ‘Alemãzinha’ performed better in the spring cycle when managed under plastic cover and was more productive, with a longer productive cycle and larger fruits.

Nas principais regiões produtoras de pêssego, o raleio é executado de forma manual, exigindo elevada disponibilidade mão de obra e custo dessa prática. O raleio mecânico pode ser uma alternativa ao raleio manual de frutos. Deste modo, o objetivo deste trabalho foi avaliar a eficiência do raleio mecânico com distintos equipamentos em pessegueiros. O experimento consistiu dos seguintes tratamentos: raleio manual de frutos, raleio mecânico de flores com o equipamento Carpa Electro®, raleio mecânico de flores com o equipamento derriçadeira e raleio mecânico nos frutos com o equipamento derriçadeira. As variáveis avaliadas, a campo foram percentagem de queda de flores e frutos, frutificação efetiva, tempo de raleio, número de frutos por planta, massa média dos frutos e produção por planta. O raleio manual e o raleio mecânico de flores com o equipamento derriçadeira foram eficazes para aumentar a produção e o diâmetro dos frutos. O raleio mecânico de flores e frutos constituem-se como uma alternativa ao raleio manual de pessegueiros, devido à capacidade de remoção e a redução de tempo para a realização da pratica do raleio.

In the major peach producing regions, thinning is performed manually, this practice requires high labor availability and cost. Mechanical thinning may be an alternative to manual fruit thinning. In this way, the objective of this work was to evaluate the efficiency of mechanical thinning with different equipment hand conducted in peach trees. The experiment consisted of the following treatments: hand thinning, mechanical flower thinning with the Carpa Electro® equipment, mechanical flower thinning with the trimming equipment and mechanical thinning of the fruits with the trimming equipment. The variables evaluated in the field were percentage of flower and fruit removed, effective fruiting, thinning time, number of fruits per plant, average fruit mass and yield per plant. The hand thinning and mechanical thinning of the flowers with the trimming equipment are effective to increase the yield and fruit size =. Mechanical thinning of flowers and fruits is an alternative to the manual peach tree thinning, due to the capacity of flower and fruit fall and the reduction of the time to thinning perform practice.

RESUMO Considerando a importância econômica da cultura do morangueiro no Brasil, com tendência clara de migração da produção no solo para sistemas inovadores de produção em substratos, é fundamental a avaliação das cultivares disponíveis no mercado quanto a tolerância a patógenos com potencial de infestação. Avaliou-se a resistência de oito cultivares comerciais (Festival, Camino Real, Camarosa, Oso Grande, Monterey, San Andreas, Aromas e Albion) a espécies de Meloidogyne e Pratylenchus. Cultivares de morango, mantidas em vasos individuais com solo esterilizado, foram inoculadas com 5.000 ovos + juvenis de segundo estágio de Meloidogyne arenaria, M. incognita, M. javanica ou M. hapla ou 1.000 espécimes de Pratylenchus zea ou P. brachyurus por planta. O experimento foi conduzido sob condições de casa de vegetação em delineamento inteiramente casualizado com seis repetições, utilizando-se plantas de sorgo ‘506’ e tomate ‘Rutgers’ como controles para o nematoides das galhas e das lesões radiculares, respectivamente. Noventa dias após a inoculação, foi avaliado o fator de reprodução dos nematoides (RF = população final / população inicial) para determinar a resistência dos genótipos de morango a cada espécie de fitonematoide. Todas as cultivares se comportaram como resistentes (FR<1,00) ou imunes (FR= 0,00) a M. javanica, M. incognita, P. zeae e P. brachyurus. Apenas ‘Camarosa’ foi suscetível (FR> 1,00) a M. arenaria e M. hapla e ‘Oso Grande’ comportou-se como suscetível a M. hapla; porém, as demais cultivares foram resistentes a estas duas espécies do nematoide das galhas. As cultivares de morango avaliadas neste trabalho comportaram-se como más hospedeiras dos nematoides estudados e, podem ser consideradas alternativa de cultivo em áreas infestadas com os patógenos.

ABSTRACT Considering the economic importance of strawberry in Brazil, with a clear migration trend from the soil to innovative systems on substrates, it is fundamental to evaluate the available cultivars in the market regarding tolerance to pathogens with potential for infestation. The reaction of eight commercial strawberry cultivars (Festival, Camino Real, Camarosa, Oso Grande, Monterey, San Andreas, Aromas, and Albion) to Meloidogyne and Pratylenchus species was evaluated. Strawberry cultivars were maintained in individual pots with sterilized soil and inoculated with 5,000 eggs + second stage juveniles of Meloidogyne arenaria, M. incognita, M. javanica or M. hapla or 1,000 specimens of Pratylenchus zea or P. brachyurus per plant. The experiment was carried out in a completely randomized design with six replications using tomato ‘Rutgers’ and sorghum ‘506’ plants as control to root-knot and lesion nematodes, respectively. Ninety days after inoculation, the nematode reproduction factor (RF= final population/initial population) was evaluated to determine the resistance of the strawberry genotypes to each nematode species. All cultivars behaved as resistant (FR<1.00) or immune (FR= 0.00) to M. javanica, M. incognita, P. zeae and P. brachyurus. The cultivar ‘Camarosa’ was susceptible (FR>1.00) to M. arenaria and M. hapla and ‘Oso Grande’ behaved as a good host to M. hapla; however, the other cultivars were resistant to these two Meloidogyne species. The assessed cultivars are poor hosts, being an alternative to be used in infested areas with these pests.

Resumo Na produção de pêssegos, o raleio é realizado convencionalmente nos frutos, de forma manual, necessitando ser realizada num curto período de tempo e com mão de obra especializada, o que eleva os custos operacionais desta prática. O raleio mecânico pode ser uma alternativa ao raleio manual de frutos. Deste modo, o objetivo deste trabalho foi avaliar o efeito do raleio mecânico em flores, com distintos equipamentos, em seleções avançadas de pessegueiros. O experimento foi conduzido nos anos de 2016 e 2017, combinando-se seleções avançadas de pessegueiros e métodos de raleio. As variáveis avaliadas foram: percentagem de raleio de flores, tempo de raleio, número de frutos por planta, produção por planta, produção estimada, massa média dos frutos e classe de diâmetro dos frutos. O raleio mecânico de flores altera os índices produtivos dos pessegueiros. O raleio mecânico em pessegueiros foi eficiente no raleio de flores e reduziu o tempo de execução da prática. Portanto, o raleio mecânico de flores é uma alternativa ao raleio manual de frutos de pessegueiros.

Abstract In cultivation of peaches, thinning is conventionally performed on fruits by hand, and needs to be done in a short time and with specialized labor, which increases the operational costs of this practice. Mechanical thinning can be an alternative to manual fruit thinning. Thus, the objective of this study was to evaluate the effect of mechanical flower thinning with different equipment in advanced peach orchard. The experiment was conducted in 2016 and 2017, combining advanced selections of peach trees and thinning methods. The evaluated variables were percentage of flowers thinning, thinning time, fruit number per plant, plant production, estimated yield, average fruit mass and fruit diameter class. Flower mechanic thinning alters the yield index of peach trees. Mechanical thinning on peach trees was efficient in flower thinning and reduced the practice execution time. Therefore, mechanical thinning is an alternative to the manual fruit thinning of peach trees.

ABSTRACT Graft incompatibility is a phenomenon associated with complex physiological, biochemical, and genetic interactions between scion and rootstock. The main objective of this work was to assess the role of cyanogenic glycosides (CGs), amygdalin and prunasin, in the graft incompatibility of Prunus and possible biochemical effects in compounds of the phenylpropanoid pathway. Graft compatibility, amygdalin and prunasin content, phenylalanine ammonia-lyase activity, total phenolic compounds content and antioxidant activity, were studied in different graft combinations (Chimarrita/Capdeboscq; Chimarrita/Tsukuba 1; Chimarrita/Umezeiro; Maciel/Capdeboscq; Maciel/’Tsukuba 1; Maciel/Umezeiro) and ungrafted genotypes. The results indicate that there was graft incompatibility of Chimarrita and Maciel cultivars grafted into Umezeiro rootstock. Combinations identified as incompatible showed higher prunasin concentration and phenylalanine ammonialyase (PAL) activity in rootstock and greater concentration of total phenolics compounds and antioxidant activity in scion and rootstock. The results indicate that large differences in CGs concentration, especially prunasin, can be the graft incompatibility cause between Prunus persic. and P. mume. The prunasin concentration may be considered a promising marker to predict graft compatibility between P. persica and P. mume.

Resumo: O objetivo deste trabalho foi avaliar o efeito da adubação nitrogenada na composição mineral das folhas, no crescimento inicial e na produção inicial de seleções avançadas de pessegueiro (Prunus persica) cultivadas em alta densidade de plantio. O experimento foi conduzido entre 2012 e 2015 em delineamento em blocos ao acaso, com a combinação de seleções avançadas de pessegueiro 'Cascata 1513' e 'Cascata 1067' e de doses de adubação nitrogenada (0, 30, 60 e 120 kg ha-1 de N). A massa de poda, diâmetro e incremento do diâmetro de tronco, volume de copa, altura de plantas, comprimento de ramos, número de gemas por centímetro de ramo, índice de clorofila, área foliar, incidência de ferrugem, produção média e o número e a massa de frutos foram avaliados. O genótipo influencia o crescimento vegetativo e o desempenho produtivo do pessegueiro. A aplicação de N em pomares adensados promove maior crescimento vegetativo das plantas e aumenta o teor do nutriente nas folhas. A produção inicial é influenciada pela adubação nitrogenada. A recomendação de adubação nitrogenada feita até o presente é insuficiente para pessegueiros conduzidos em sistemas de produção adensada.

Abstract: The objective of this work was to evaluate the effect of nitrogen fertilization on the mineral composition of leaves, initial growth, and yield of peach (Prunus persica) tree advanced selections grown at a high-planting density. The experiment was carried out between 2012 and 2015 in a randomized complete block design, with a combination of advanced selections of the 'Cascata 1513' and 'Cascata 1067' peach trees and of N fertilization doses (0, 30, 60, and 120 kg ha-1 N). Green weight after pruning, diameter, and increase of trunk diameter, canopy volume, plant height, branch length, number of buds per centimeter of shoot, chlorophyll index, leaf area, rust incidence, average production, number of fruit, and mass of fruit were evaluated. Genotype affects the vegetative growth and productive performance of peach trees. The application of N to dense peach orchards promotes a greater vegetative growth of the plants and increases the content of the nutrient in leaves. The initial production is affected by N fertilization. The recommendation of N fertilization made to date is insufficient for peach trees at high-density management systems of production.