Correlation of biometric characteristics of fruits and seeds with the vigor of Agonandra brasiliensis seedlings in northern Amazonia

The goal of this study was to determine and correlate the main morphometric characteristics of fruits, seeds, and seedling vigor of Agonandra brasiliensis, in Roraima. The design was completely randomized with three treatments, consisting of six replications with 20 seeds. The treatments established were three classes of seeds: T1 - small seeds (S = 1.50-1.69 g); T2 - medium seeds (M = 1.70-1.89 g) and T3 - large seeds (L = 1.90-2.09 g). The variables evaluated were: length; diameter; the fresh mass of fruits and seeds; percentage, speed (in index) and average time of emergence, length of roots and aerial part; number of leaves; fresh, dry and total seedling mass; seedling lignification index; root/shoot ratio and dry root/shoot ratio and correlations between all studied variables. The fresh mass of the fruit of Agonandra brasiliensis has a high positive correlation with the mass of seeds. Small seeds of Agonandra brasiliensis exhibit a higher percentage of emergence in the conditions of the northern Amazon.

Gas exchanges and chlorophyll content in green pepper plants under bio-fertilization and times of application

This study aimed to determine the gas exchange and the chlorophyll content of green pepper plants under doses and times of application of bio-fertilizers based on manure and enriched organic compost. Two experiments were carried out simultaneously with applications of bio-fertilizers prepared from manure and enriched organic compost, one using cattle manure (CBF) and the other sheep manure (SBF). For these, four doses of biological fertilizers (100, 200, 300 and 400 dm³ ha-1), three application times (0, 30 and 60 days after transplantation - DAT) and absolute control, referring to the absence of fertilization, were used. treatments. were arranged in a randomized block design, totaling 13 treatments. The variables evaluated were: the relative chlorophyll a, b and total content; liquid photosynthesis (A); stomatal conductance (gs); internal CO2 concentration (Ci); instant carboxylation efficiency (iCE - A/Ci); transpiration rate (T); intrinsic water use efficiency (iWUE - A/gs); and water use efficiency (WUE - A/E). Gs, A and T, showed significant effect at 60 DAT with the application of SBF and Ci at 30 DAT with CBF. The dose of 400 dm³ ha-1 of SBF provided greater gas results, and the doses of 200 and 300 dm³ ha-1 of CBF promoted a greater Ci, greater stomatal conductance, greater liquid photosynthesis and better water use efficiency, which results in a greater plant fresh weight at the time of flowering induction.

Macronutrient uptake, transport and use efficiency in seedlings of Pochota fendleri produced in different substrates / Eficiência de absorção, transporte e utilização de macronutrientes por mudas de Pochota fendleri produzidas em diferentes substratos

Seedlings produced in containers can be influenced by the materials used in the substrate, which affects the robustness of the plants and, indirectly, the time required for transplanting and for the plants to become established in the field. The aim of this study was to determine the chemical properties of different materials and on the absorption of macronutrients in Pochota fendleri seedlings (cedro-doce). The treatments were: sand (Sa), soil (So), sand+soil (Sa+So), and sand+soil+crushed Brazil nut capsules (Sa+So+CNC). The growth and macronutrient content were evaluated at 60 days after thinning. The amount of macronutrients in the substrate increased with the addition of crushed Brazil nut capsules. The use of different materials for the substrate, particularly Sa+So+CNC, had a positive influence on the morphological characteristics of seedlings, which ensuring high rates of establishment and survival after outplanting, making commercial reforestation with Pochota fendleri attractive.

As mudas produzidas em recipientes podem ser influenciadas pelos materiais utilizados no substrato, que afetam a robustez das plantas e, indiretamente, o tempo necessário para o transplante e o estabelecimento das plantas no campo. O objetivo deste estudo foi determinar as propriedades químicas de diferentes materiais e a absorção de macronutrientes em mudas de Pochota fendleri (cedro-doce). Os tratamentos foram: areia (Sa), solo (So), areia + solo (Sa + So) e areia + solo + casca de ouriço da castanha do Brasil triturada (Sa + So + CNC). O crescimento e o teor de macronutrientes foram avaliados 60 dias após o desbaste. A quantidade de macronutrientes no substrato aumentou com a adição de casca de ouriço da castanha do Brasil triturada. O uso de diferentes materiais para o substrato, principalmente o Sa + So + CNC, influenciou positivamente as características morfológicas das mudas, garantindo altas taxas de estabelecimento e sobrevivência após o plantio, tornando atraente o reflorestamento comercial com Pochota fendleri.

Water absorption and method improvement concerning electrical conductivity testing Acacia mangium (Fabaceae) seeds.

Acacia is an important forest species of rapid growth whose seeds have tegument dormancy. In this work it was intended to characterize water absorption pattern after seed dormancy break, and to determine the amount of water, container size and the need of breaking the tegument dormancy, as to perform electrical conductivity test in small and large seeds of Acacia mangium (Fabaceae). The seeds were collected from 10, 8 and 6 years old trees established in poor yielding-capacity soils on savannah areas of Roraima, Brazil; seeds were classified in six lots concerning to seed size and tree age. Germination tests (50 seeds and four replications per lot) were carried out on germitest® paper maintained on gerbox at 25 °C. Imbibition was verified by seed weighing at different times (0, 2, 5, 8, 12, 16, 24, 36, 48, 60, 72, 84, 96 and 120 hours). The electrical conductivity test consisted of three experiments, distinguished by the amount of water used and by the container size in which seeds were immersed. Seeds of A. mangium coming from 10 years old trees presented increased germination percent and germination speed than seeds of six-year old trees. Small seeds presented increased in electrical conductivity and water absorption until 120 hours when compared to large seeds. The immersion of seeds of A. mangium in 40 mL of distilled water into 180 mL plastic containers, after dormancy break, it is indicated for the determination of electrical conductivity test. The ratio of electrolytes by seed mass, after 24 hours of immersion in water, turns electrical conductivity test more accurate concerning A. mangium seeds.

Variabilidade genética de acessos de araçazeiro e goiabeira suscetíveis e resistentes a Meloidogyne enterolobii / Genetic variability of araça and guava accessions susceptible and resistant Meloidogyne enterolobii

A goiabeira representa uma importante atividade frutícola no Brasil, com mercado cada vez maior. Porém, desde 1989 vêm sendo relatados severos danos à cultura, causados pelo nematóide Meloidogyne enterolobii. Uma das alternativas para solucionar esse problema é a utilização de porta-enxertos com resistência a este patógeno. Este trabalho teve por objetivo a caracterização molecular, com marcadores RAPD, de acessos de Psidium testados quanto à resistência a M. enterolobii e quanto à compatibilidade como porta-enxertos para as goiabeiras comerciais. Foram testados 30 primers, dos quais 19 forneceram resultados nítidos para a amplificação. Foram gerados 163 fragmentos, dos quais 86 polimórficos (63,0%). Em média, cada iniciador produziu 8,6 fragmentos, dos quais 5,4 apresentaram polimorfismo. A análise de agrupamento foi realizada por espécie, os acessos de Psidium sp apresentaram a formação de dois grupos, um formado pelo acesso A-UFLA e o segundo subdividido em quatro subgrupos, sendo os acessos com maiores distâncias genéticas A-Ufla, resistente a M. enterolobii, A-Ufla4 e A-Ufla5, ambos suscetíveis ao nematoide em questão, todos coletados em Lavras-MG, com similaridade aproximada de 66%. Na análise de agrupamento, dos treze acessos de P.cattleyanum, foi possível constatar a formação de dois grandes grupos. Um formado por três acessos suscetíveis a M. enterolobii (A-20.2, A-10.1 e A-9.2) e outro grupo formado por dez acessos. Os acessos se agruparam, conforme a região de origem, em seis grupos, sendo que o mais divergente é originário da região de Lavras - MG, com 0,65 de similaridade, onde as distâncias genéticas variaram de 0,88 a 0,65. Dos treze acessos de P. guineense, todos suscetíveis a M. enterolobii, sendo 12 oriundos de Recife e um de Pelotas (A-14.1) e agruparam-se em dois grupos com similaridades variando de 0,59 a 0,83. Quanto ao estudo de diversidade entre os acessos de goiabeiras, a maior distância genética foi detectada entre o acesso G-Ufla com 0,71 Lavras-MG.

Guava culture stands for an important fruit-growing business in Brazil, with a greater and greater market. But, since 1989 severe damages to the culture caused by the nematode Meloidogyne enterolobii, have been reported. One the alternatives to solve this problem is the use of rootstocks with resistance to this nematode. This research aimed at the molecular characterization, with RAPD markers, of Psidium accessions susceptible to be utilized as rootstocks for the commercial guava trees. 30 primers were tested, from which 19 supplied distinct results for the amplification. The primers generated 163 polymorphic marks, resulting into a mean of 8,6 polymorphic bands per primer. The cluster analysis was performed per species, the accessions of Psidium sp presented the formation of two groups, one formed by A-UFLA accession and the other subdivided into four subgroups, that is, the accession with increased genetic distances, A-Ufla, resistant to M. enterolobii, A-Ufla4 and A-Ufla5, both susceptible to the nematode in issue, all collected in Lavras-MG with a similarity of about 66%. In the cluster analysis of the thirteen accessions of P.cattleyanum, it was possible to found the formation of two great groups. One made up by three accessions susceptible to M. enterolobii (A-20.2, A-10.1 and A-9.2) and the other group formed by ten accessions. The accessions grouped together according to the region of origin in six groups, the most divergent being that native to region of Lavras - MG, with 0.65 of similarity, where the genetic distances ranged from 0.88 to 0.65. The thirteen accessions of P. guineense, all susceptible to M. enterolobii, namely, 12 coming from Recife and one proceeding from Pelotas (A-14.1), grouped themselves together and two groups with similarity ranging from 0.59 to 0.83. As to the diversity study among the guava tree accessions, the greatest genetic distances were detected between the accessions G.P.S and G-Ufla with 0,71 Lavras-MG.

Production of peach grafts under hydroponic conditions / Produção de mudas de pêssego enxertadas em sistema hidropônico

The objective of the present work was to study the feasibility of producing Okinawa rootstocks and peach grafts using a hydroponic system. The study was conducted in two phases. The growth and development of Okinawa rootstocks under hydroponic conditions were determined in the first phase, and in the second phase, the viability of grafting production of peach cultivars Aurora and Diamante associated with different types of rootstocks. The parameters analysed were the time required for 60 to 75 percent plants to reach the stages of transplanting (15 cm height) and grafting (4 to 6 cm stem diameter), the percentage of sprouting grafts determined 20 days after grafting, and the height of the shoots measured every 7 days until grafts were 40 cm high measured from the crown. Although 13 percent of the Okinawa rootstocks grown under hydroponic conditions presented undesirable genetic segregation characteristics, transplanting was reached at 30 days after transference (DAT) to hydroponic conditions and grafting at 61 DAT. Proximal pruning at 5 cm gave rise to grafts of 47.53 cm in height at 116 DAT, and both cultivar showed 100 percent graft sprouting with the cultivar Aurora presenting higher growth.

Conduziu-se este trabalho, com o objetivo de estudar a viabilidade da produção de porta-enxerto 'Okinawa' e de mudas enxertadas em sistema hidropônico. O experimento foi conduzido em duas etapas. Na primeira etapa, pesquisaram-se o tempo de germinação e o desenvolvimento vegetativo das plantas do porta-enxerto 'Okinawa' e na segunda etapa a viabilidade de produção de mudas enxertadas de pêssego das cultivares 'Aurora' e 'Diamante', associada a diferentes tipos de desmama dos enxertos. As características avaliadas referiram-se ao tempo para que 60 a 75 por cento das plântulas atingissem o ponto de repicagem (15 cm de altura) e o ponto de enxertia (diâmetro de 4 a 6 mm) coletados semanalmente, a percentagem de pegamento da enxertia foi avaliada aos 20 dias após a enxertia e o crescimento em altura dos enxertos (brotos), tomadas semanalmente, até atingirem 40 cm de altura. Embora cerca de 13 por cento dos porta-enxerto de 'Okinawa' tenham se apresentado com aparência arbustiva e ananicante, características impróprias ao futuro desenvolvimento normal das mudas, o ponto de repicagem dos porta-enxertos foi atingido aos 30 dias após transferência para solução nutritiva (DAT) e o ponto de enxertia aos 61 DAT. A desbrota a 5 cm foi a mais apropriada à propagação de mudas de pessegueiro, estando as mesmas prontas para a comercialização aos com 47,53 centímetros de altura aos 116 DAT e ambas as cultivares apresentaram índice de pegamento de 100 por cento, sendo que a cultivar Aurora apresentou maior crescimento.