-The present study evaluated the germination potential of seeds from eight peach tree rootstocks under different stratification methods, aiming at the production of high quality seedlings. In the first experiment, seeds with endocarp from eight genotypes ('Aldrighi', 'Capdeboscq', 'Flordaguard', 'Okinawa', 'Okinawa roxo', 'Tsukuba 1', 'Tsukuba 2', 'Tsukuba 3') were stratified on sand and moist vermiculite, at 7 ºC for 60 days. In the second experiment, endocarpless seeds of the same genotypes were stratified on Petri dishes at 7 ºC. In the third experiment, the time at which at least 75% of the seedlings reached transplanting height (15 cm high) was verified. The endocarp was a limiting factor for seed germination of the eight rootstocks, since the highest germination percentages were 21% and 48.3% for 'Aldrighi' and 'Capdeboscq', respectively. Germination of 'Okinawa' was only 19.2% and 4.2%, in sand and vermiculite, respectively. Seeds stratified without the endocarp, showed 100% germination, except for 'Flordaguard' and 'Tsukuba 2' and 3', with 93% germination. Seed mass presented a positive correlation with the germination speed index and the initial growth of the seedlings. 'Aldrighi' and 'Capdeboscq' presented more vigorous seedlings with greater growth in height, stem diameter, and Dickson quality index.

A meloidoginose da goiabeira, causada por M. enterolobii (= M. mayaguensis), é hoje considerado o principal problema fitossanitário desta cultura em todo o País, pois sua incidência resulta em acentuada queda de produtividade e, na maioria das vezes, a morte das plantas em médio prazo. Visando a seu controle, objetivou-se neste trabalho identificar fontes de resistência em goiabeira Psidium guajava L e araçazeiro Psidium sp.. Foram avaliados onze genótipos oriundos do Câmpus da Universidade Federal de Lavras (UFLA) e de regiões próximas ao município de Lavras (MG). As sementes foram coletadas de frutos fisiologicamente maduros e germinadas em piscinas hidropônicas. Ao atingirem 12 cm de altura, foram transferidas para casa de vegetação, em vasos individuais, e mantidas a temperatura entre 18-38°C. Após quinze dias, foram inoculados individualmente com suspensão de 10.000 ovos e juvenis de segundo estádio (J2) de M. enterolobii e avaliadas após 120 dias. As reações dos hospedeiros foram enquadradas nos parâmetros estabelecidos pelo fator de reprodução FR, estimado pelo quociente Pf/Pi, em que Pf representa a população final e Pi a população inicial. O delineamento utilizado foi o inteiramente casualizado, com 11 genótipos, uma espécie de nematoide e seis repetições, sendo duas plantas em cada genótipo adicionadas como controle. Quatro meses depois, foram avaliados os teores foliares de macro e micronutrientes e o grau de infecção de cada genótipo. A produção média de ovos e J2 de M. enterolobii variou de 200 a 428.146,1, e os fatores de reprodução (FR) médios variaram de 0,02(ALU1) a 42,81(A-PASTO). Os genótipos de araçazeiro (Psidium spp.) AUFLA1, AUFLA4, AUFLA5 e APASTO e os genótipos de goiabeira (P. guajava) G-ROXA e G-AMAR foram considerados suscetíveis. Os genótipos de araçazeiro ALU1, ALU2, ALU3, AROXO-C e AROXO-U mostraram-se resistentes, reforçando a necessidade de trabalhos complementares com essas espécies para uso como porta-enxerto em cultivares comerciais de goiabeira. A absorção de macro e micronutrientes é alterada quando os genótipos de Psidium spp. são inoculados com o fitonematoide M. enterolobii.

-This study aimed at determining and correlating the main morphometric characteristics of fruits and seeds with the germination potential and vigor of eight peach rootstocks. The experimental design was completely randomized, with four replications of 50 seeds per treatment. The analyzed variables were: length, width, thickness, fresh mass of fruit and seeds, moisture content of seeds, percentage of seeds attacked by fungi and intact seeds, germination percentage, germination speed index (GSI) and mean germination time (MGT). The Capdeboscq, Aldrighi and Tsukuba 1 cultivars showed higher values of length, width, thickness and fresh mass of seeds compared to other cultivars, presenting a relationship with the later period of fruit ripening. Regardless of the fruit ripening time, the germination percentage was high, ranging between 93% and 100% for all cultivars. In addition, the fresh mass of fruits has showed a high positive correlation with the fresh mass of seeds for the eight evaluated peach rootstocks. The GSI and MGT have a high relationship with the fresh mass of seeds.Index terms: Rosaceae, morphobiometry, seeds, cultivars, peach.Correlação de características biométricas de frutos e sementes com a germinação e vigor de porta-enxertos de Prunus persica RESUMO -Objetivou-se determinar e correlacionar as principais características morfométricas de frutos e sementes sobre o potencial de germinação e o vigor de oito porta-enxertos de pessegueiro. O delineamento experimental foi inteiramente casualizado com quatro repetições de 50 sementes por tratamento. As variáveis analisadas foram: comprimento, largura, espessura, massa fresca dos frutos e sementes, grau de umidade de sementes, porcentagem de sementes intactas e infectadas por fungos, porcentagem de germinação, índice de velocidade de germinação (IVG) e tempo médio de germinação (TMG). As cultivares Capdeboscq, Aldrighi e Tsukuba 1 apresentaram maiores valores médios de comprimento, largura, espessura e massa fresca de sementes comparados com as demais cultivares, apresentando relação com o período mais tardio de maturação dos frutos. Independente da época de maturação dos frutos, a porcentagem de germinação foi alta variando entre 93% e 100% para todas as cultivares. Somado a isso, a massa fresca do fruto apresenta alta correlação positiva com a massa fresca das sementes dos oito porta-enxertos de pessegueiro avaliados. O IVG e o TMG possuem alta relação com a massa fresca das sementes.

The aim of this study was to verify the effect of different substrates, in the presence and absence of controlled-release fertiliser, on the growth and morphological quality of seedlings of Agonandra brasiliensis Miers ex Benth. & Hook.f., in the state of Roraima, Brazil. The experimental design was a 2 * 5 factorial scheme, with and without the addition of 1.0 g L-1 NPK 18-05-09 formulation controlled-release encapsulated fertiliser (Forth CoteR) and five substrates. The following were evaluated: shoot height (H), collar diameter (CD), increase in shoot length (IncH) and collar diameter (IncCD), shoot dry weight (SDW), root dry weight (RDW), total dry weight (TDW) and Dickson quality index (DQI). The use of NPK 18-05-09 formulation controlled-release fertiliser (Forth CoteR) in a medium-sand substrate is recommended for obtaining plants of Agonandra brasiliensis of greater robustness, balance of biomass distribution, and a high standard of quality. In the substrate composed of soil from the cerrado + carbonised rice husks - CRH + organic substrate (2:1:1), the addition of NPK 18-05-09 formulation Forth CoteR is not necessary to obtain Agonandra brasiliensis plants of good morphological quality. Substrate 3, composed of soil + CRH (3:1), with or without the addition of NPK 18-05-09 formulation Forth CoteR, is not recommended for producing plants of Agonandra brasiliensis, due to the slow development and reduced morphological quality of the plants.

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% 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% 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% graft sprouting with the cultivar Aurora presenting higher growth.

Abstract: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. Rev. Biol. Trop. 64 (4): 1651-1660. Epub 2016 December 01.

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The continuity of the research will certainly allow the development of reliable procedures for other species, besides allowing the identification of wider alternatives for the use of this system for the expansion of knowledge in the areas of physiology and evaluation of the physiological potential of seeds.