ABSTRACT The aim of this study was to evaluate the genotypes developed by the Peach Breeding Program at the Federal University of Viçosa, as regards to resistance to M. incognita. Six rootstocks genotypes propagated by cuttings (713-07, 713-13, 913-3, 913-6, 913-11 and 913-17) and two rootstocks propagated by seeds (‘Okinawa’ and hybrid between scion cultivars Aurora 2 x Aurora 1), were evaluated. The experimental design was randomized block design with five replicates and one plant per experimental units. After establishing the plants in pot, maintained in a greenhouse, this were inoculated with 11.000 juveniles + eggs of M. incognita. Evaluations were performed at 140 days after inoculation. The roots were evaluated and the number of galls and egg mass in the roots were determined. The eggs were extracted from each plant for quantification and determination of the Reproduction Factor (RF) of the nematode. The peach genotypes 913-3, 913-6, 913-11, 913-17 and 713-7 showed an immune reaction to M. incognita. Genotype 713-13 showed susceptible reaction to M. incognita. The hybrid between scion cultivars Aurora 2 x Aurora 1 confirmed susceptible.

Abstract The aims of this study were to estimate genetic parameters, predict genotypic values, and analyze the genotypic divergence in S0 and S1 peach trees evaluated in a subtropical environment by the mixed model methodology. For this, twenty-two clones were evaluated for plant and fruit traits. Genotypic variance among clones was significant. The individual broad-sense heritabilities ranged from 0.11 to 0.84, and the individual repeatability coefficients ranged from 0.15 to 0.89. The genotypic coefficients of variation were higher than 10% for most of the traits. Clustering based on plant and fruit traits led to the formation of two and five mutually exclusive groups, respectively. Multivariate analysis of principal components indicated that some traits could be excluded from genetic evaluation. Considering the yield trait and the selection of five clones, predicted gain from selection was 70%, which shows the possibility of considerable genetic progress from clonal selection in peach trees.

RESUMEN El objetivo de este estudio fue determinar la tolerancia al estrés hídrico y salino en cuatro especies cultivadas de Passiflora L. Se evaluaron 11 accesiones de cuatro especies de Passiflora de interés comercial provenientes de diferentes plantaciones. El diseño experimental fue en parcelas subdivididas, donde la parcela principal fue el porcentaje de saturación de agua en relación con los requisitos del cultivo (33 y 100%). La subparcela se estableció por los niveles de saturación de sal (cloruro de sodio nivel reactivo - 99,9% de pureza) (CE: 1.50 y 5.5 dS m-1) con 11 accesiones en una disposición completamente aleatoria, con cinco repeticiones, donde la unidad experimental fue una planta. Los resultados mostraron que las accesiones m11, m13 (P. edulis f. flavicarpa) y m15 (P. tarminiana) se consideraron tolerantes a la salinidad y la sequía; las accesiones m2 (P. edulis f. edulis), m12 y m14 (P. edulis f. flavicarpa) fueron moderadamente tolerantes. Estas observaciones son la base para futuros estudios de tolerancia a la sequía en Passiflora, que deben ser seguidos por evaluaciones de campo.

ABSTRACT The aim of this study was to determine tolerance to water and salt stress in four cultivated Passiflora L. species. Eleven accessions of four Passiflora species of commercial interest from different plantations were evaluated. The experiment design used sub-split plots, where the plot was the percentage of water saturation in relation to the requirements of the crop (33 and 100%). The subplot was established with the saturation levels of salt (sodium chloride reactive level - 99.9% purity) (EC: 1.5 and 5.5 dS m-1) with the 11 accessions in a completely randomized array with five replications, where the experiment unit was one plant. The results showed that accessions m11, m13 (P. edulis f. flavicarpa) and m15 (P. tarminiana) were tolerant to salinity and drought; accessions m2 (P. edulis f. edulis), m12 and m14 (P. edulis f. flavicarpa) were moderately tolerant. These observations provided a basis for future studies on drought tolerance in Passiflora, which must be followed up with field evaluations.

RESUMO: O cultivo do pessegueiro em regiões de inverno ameno é viabilizado pela utilização de genótipos que apresentam baixa necessidade de frio, sendo este um dos principais objetivos do melhoramento para essas regiões. Assim, os objetivos deste estudo foram estimar parâmetros genéticos, avaliar a variabilidade genética e selecionar famílias adaptadas a regiões de inverno ameno em geração S1 de pessegueiros via metodologia de modelos mistos (REML/BLUP). Para isso, 22 populações, 84 famílias e 2090 indivíduos foram avaliados quanto as características: taxa de brotação (TB), densidade de nós (DN), altura da planta (AP) e diâmetro do tronco (DT). Verificou-se variabilidade genética para todas as características. As herdabilidades individuais no sentido amplo foram de baixa e média magnitudes. A característica AP apresentou correlação genética positiva de magnitude elevada com DT. A característica DN apresentou correlação genética negativa moderada com AP e DT. O agrupamento pelo método de Tocher resultou na formação de seis grupos mutuamente excludentes. Considerando intensidade de seleção de 25%, a seleção simultânea para TB, DN e DT propiciou ganhos preditos de 11.3% para TB, 9.7% para DN, -14.2% para AP e -14.3% para DT, evidenciando o grande potencial do germoplasma avaliado.

ABSTRACT: The growing of peach in mild winter regions is made viable through the use of genotypes that have low need for cold conditions, and this is one of the main aims of breeding for these regions. Thus, the aims of this study were to estimate genetic parameters, evaluate genetic variability, and select families adapted to mild winter regions in the S1 generation of peach through mixed model methodology (REML/BLUP). For that purpose, 22 populations, 84 families, and 2090 individuals were evaluated for the following traits: bud burst rate (BR), node density (ND), plant height (PH), and trunk diameter (TD). Genetic variability was found for all the traits. Individual heritability in the broad sense was of low and medium magnitudes. The PH trait had positive genotypic correlation of high magnitude with TD. The ND trait had moderate negative genotypic correlation with PH and TD. Clustering by the Tocher method resulted in the formation of six mutually exclusive groups. Considering selection intensity of 25%, simultaneous selection for BR, ND, and TD led to predicted gains of 11.3% for BR, 9.7% for ND, -14.2% for PH, and -14.3% for TD, showing the great potential of the germplasm evaluated.

Resumo A propagação seminífera de maracujá azedo (Passiflora edulis Sims) é o principal tipo de multiplicação devido à facilidade na formação de mudas. No entanto, o reduzido número de cultivares produtivas e homogêneas reflete a necessidade de melhoramento genético. O objetivo deste trabalho foi avaliar os efeitos maternos e recíprocos no vigor e na germinação de sementes de maracujá. O experimento foi conduzido em delineamento inteiramente casualizado, no esquema fatorial, com duas estruturas genéticas (híbrido e recíproco) e dez cruzamentos, com quatro repetições (50 sementes), em bandejas contendo areia inerte na câmara de germinação. Antes da semeadura, foi obtido o peso de 100 sementes, e aos 28 dias, foram avaliados a porcentagem de germinação, o índice de velocidade de emergência, comprimento total de plântulas, comprimento de parte aérea e raiz principal, número de plântulas normais e massa seca por plântulas. Os efeitos recíprocos dizem qual genótipo é mais promissor quando usado como genitor feminino ou masculino para a característica estudada. Pode-se inferir que há efeito materno influenciando o peso de 100 sementes, a emergência, o índice de velocidade de emergência e o número de mudas normais. Houve influência dos pais na expressão de caracteres em sementes de maracujá azedo. É importante definir os pais paterno e materno para obter sementes com alto potencial de germinação.

Abstract The seminiferous propagation of Sour Passion Fruit (Passiflora edulis Sims) is the main kind of multiplication due to the ease formation of seedlings. However, the reduced number of productive and homogeneous cultivars reflects the need for genetic breeding. The objective of this study was to assess the maternal and reciprocal effects in vigor and germination of Sour Passion Fruit seeds. The experiment was conducted in a completely randomized design in the factorial scheme, with two structure (hybrid and reciprocal) and ten crosses with four replicates (50 seeds) in trays containing inert sand in germination chamber. Before sowing, it was obtained the weight of 100 seeds, and at 28 days germination percentage, emergence speed index, total seedlings length, shoot length and main root length, number of normal seedlings and dry mass per seedlings were evaluated. The reciprocal effects tell us which genotype is most promising when used as the female or male parent for the trait studied. It can be inferred that there is maternal effect influencing the weight of 100 seeds, emergence, emergence speed index and the number of normal seedlings. There was influence of the parent on the expression of traits in seeds of Sour Passion Fruit. It is important to define the paternal and maternal parent to obtain seeds with high germination potential.

Abstract This study was conducted to identify the allelic interactions and genetic effects involved in genetic control of quantitative traits in Capsicum annuum. Six generations (P1, P2, F1, F2, BC1 and BC2) were used to study the variances, means and allelic interactions of 16 quantitative traits evaluated. The additive part of the phenotypic variance found for plant height, number of peppers per plant, days to flowering and days to fruiting lead to the conclusion that phenotypic selection in the F2 generation are likely effective in obtaining genetic gains. According to the reduced model, the traits of canopy width, fruit width and number of seeds per fruit were not influenced by epistatic effects, but only by additive and dominant effects, which allows selection of superior individuals in segregating generations or improvement of these traits by means of hybridization.

RESUMO Muitos fatores ambientais afetam a fase de pós-produção das plantas ornamentais. A exposição ao etileno é um dos fatores mais importantes que afetam a qualidade de muitas plantas ornamentais em vaso. O trabalho teve como objetivo identificar genótipos de pimenta resistentes ao etileno na fase de pós-produção das pimentas de vaso. Onze cultivares de pimentas foram utilizadas, quando as plantas apresentaram 30% dos frutos maduros, foram transferidas para um recipiente hermético de 90 L e tratados com etileno à 10 μL L–1 por 48 horas, em seguida, mantidas à temperatura ambiente para posterior análise dos efeitos do etileno. Foram feitas contagens do número de folhas e frutos no tempo zero, 48, 96 e 144 horas após o tratamento com etileno. O delineamento experimental utilizado foi inteiramente casualizado, com cinco repetições. As cultivares apresentaram taxas variadas de abscisão foliar e de frutos. O cultivar ‘Peloteira’ apresentou maior resistência ao etileno, com abscisão foliar de 19%, após 144 horas. Para característica abscisão dos frutos, os cultivares ‘Peloteira’, ‘Jalapeño’, ‘Stromboli ornamental’, ‘Malagueta’ e ‘Rocoto vermelha’ apresentaram menor porcentagem de abscisão, variando entre 9 e 34%, após 144 horas de exposição ao etileno.

ABSTRACT Many environmental factors affect the post-production shelf life of potted ornamental plants. Exposure to ethylene can reduce the quality of many species, inducing flower, fruit and leaf abscission and senescence. The present study identified ethylene-resistant pepper genotypes during post-production shelf life testing. Potted plants of eleven pepper cultivars were transferred to a 90-L sealed container when they had 30% of ripe fruits and treated with 10 μL L–1 of ethylene for 48 hours. Number of leaves and fruits were counted at the beginning of ethylene exposure and after 48, 96 and 144 hours. The experimental design was completely randomized, with five replicates of individual pots. The cultivars showed varied rates of foliar and fruit abscission. ‘Peloteira’ showed higher resistance to ethylene, with foliar abscission of 19%, after 144 hours. For fruit abscission, the cultivars ‘Peloteira’, ‘Jalapeño’, ‘Stromboli ornamental’, ‘Malagueta’ and ‘Rocoto Vermelha’ presented a lower percentage of leaf drop, varying between 9 and 34%, after 144 hours of exposure to ethylene. This study showed that ornamental peppers have high genetic diversity regarding ethylene sensitivity.

RESUMEN Passiflora tarminiana es una glicofita trepadora, nativa de la región andina que tiene tolerancia a la salinidad y estrés hídrico moderado. El objetivo de este estudio fue evaluar la capacidad para la excreción de sodio como una posible estrategia de esta especie para la tolerancia a la salinidad y a la sequía. La excreción de sal y las concentraciones de iones excretados se examinaron en plantas cultivadas durante siete meses bajo varios niveles de salinidad [(NaCl) 2,5; 4,0 y 5,5 dS m-1 (25, 40 y 55 mM)] y de estrés hídrico moderado (33 y 100% de humedad en el sustrato). El experimento fue llevado a cabo en un diseño completamente al azar con un arreglo de parcelas subdivididas, donde la parcela constituye el porcentaje de saturación de agua (33 y 100%), la subparcela los niveles de saturación de sal (CE: 2,5; 4,0 y 5,5 dS m-1), con cinco repeticiones, y la unidad experimental compuesta por una planta. Se evaluaron los cristales de sal y las estructuras de la epidermis foliar. Las sales fueron excretadas en la superficie adaxial de la hoja, posiblemente debido a las glándulas secretoras de sal especializadas. Se observaron otras estructuras como tricomas y papilas, que se cree que también están implicadas en la tolerancia a la salinidad en P. tarminiana.

ABSTRACT Passiflora tarminiana is a climbing glycophyte, native to the Andean region that has tolerance to salinity and moderate water stress. The aim of this study was to evaluate its capacity for sodium excretion as a possible strategy for salinity tolerance and the drought. Salt excretion and excreted ion concentrations were evaluated in plants grown for seven months under various levels of salinity [(NaCl) 2.5, 4.0, and 5.5 dS m-1 (25, 40 and 55 mM)] and moderate water stress (33 and 100% moisture in the substrate). The experiment design was completely randomized in a split-plot array, where the plot was determined by the percentage of water saturation (33% and 100%). The ubplot had saturation levels of salinity (EC: 2.5, 4.0, and 5.5 dS m-1), with five replicates. The experiment unit consisted of one plant. Salt crystals and structures of the leaf epidermis were evaluated. Salts were excreted in the adaxial leaf surface, possibly because of specialized salt secreting glands. Other structures, such as trichomes and papillae, were also observed, which are believed to also be involved in the salt tolerance of P. tarminiana.

RESUMO O maracujazeiro azedo é uma importante fruteira amplamente produzida e consumida no Brasil. A produção e produtividade estão ameaçadas por vários problemas fitossanitários. Uns dos mais importantes é a fusariose, causada pelo fungo Fusarium oxysporum f. sp. passiflorae. Esta doença não tem controle eficiente. Neste sentido o objetivo deste trabalho foi avaliar a resposta de plantas, em estágio de muda, de 14 espécies de Passiflora mediante a inoculação de F. oxysporum f. sp. passiflorae cultivadas em solução nutritiva. As espécies utilizadas no Screening foram: P. quadrangularis, P. nitida, P. foetida, P. tenuifila, P. alata, P. setacea, P. cincinnata, P. mucronata, P. micropetala, P. suberosa, P. morifolia, P. eichleriana P. edulis e P. coccinea. Quatro mudas de cada genótipo foram inoculadas por imersão das raízes numa suspensão de 1x106 esporos mL-1, durante 24 horas e, em seguida, transplantada para potes contendo solução nutritiva. As plantas foram avaliadas diariamente por 40 dias para a ocorrência de sintomas de murcha e morte. Foram obtidos o período de sobrevivência e a taxa de mortalidade. O método de imersão das raízes por 24 horas e a substituição de solo por solução nutritiva foi eficiente na distinção dos genótipos resistentes. Houve variabilidade intraespecíficas em relação a doença. As espécies mais resistentes foram P. foetida. P. mucronata. P. nitida e P. morifolia.

ABSTRACT Passion fruit is an important fruit vine widely produced and consumed in Brazil. Production and productivity have been threatened by several phytosanitary problems. One of the most important problems is fusariosis, caused by the fungus Fusarium oxysporum f. sp. passiflorae. This disease has no efficient control. Thus, the aim of this study was to evaluate the response of plants of 14 Passiflora species, in the stage of seedling, through inoculation of F. oxysporum f. sp. passiflorae grown in nutritive solution. The species used in the screening were P. quadrangularis, P. nitida, P. foetida, P. tenuifila, P. alata, P. setacea, P. cincinnata, P. mucronata, P. micropetala, P. suberosa, P. morifolia P. eichleriana P. edulis and P. coccinea. Four seedlings of each genotype were inoculated by immersion of roots in a suspension of 1x106 spores mL-1 during 24 hours and then transplanted into pots containing nutritive solution. Plants were daily evaluated during 40 days for the occurrence of wilt symptoms and death. The survival period and the mortality rate were obtained. The method of root immersion for 24 hours and the replacement of soil by nutritive solution were efficient in distinguishing the resistant genotypes. There was intraspecific variability in relation to the disease. The most resistant species were P. foetida, P. mucronata, P. nitida and P. morifolia.

RESUMO O conhecimento da adaptabilidade e estabilidade da produção de frutos em diferentes locais ou anos é crucial para aumentar o potencial de produção agrícola. Por isso, o objetivo deste trabalho foi avaliar a existência de interação entre cultivares e anos, bem como avaliar a estabilidade de cultivares de pessegueiro e nectarineira quanto à massa de matéria fresca de fruto, relação SS/AT e duração de ciclo nas condições de Viçosa-MG. Para isto foram avaliadas 28 cultivares de pessegueiro e duas cultivares de nectarineira pertencentes ao pomar da Universidade Federal de Viçosa nos anos de 2011, 2012 e 2013. Foram avaliados os caracteres massa de matéria fresca de fruto, relação SS/AT e duração de ciclo e utilizados os métodos Tradicional e de Eberhart & Russell (1966) para estudo da estabilidade fenotípica no tempo. A interação cultivares x anos é significativa para todas as características. ‘Josefina’ apresenta adaptabilidade geral para relação SS/AT, e ‘Flordaprince’ e ‘Tropical’ para duração de ciclo. Para ambientes favoráveis são indicadas as cultivares ‘Capdebosq’ e ‘Maciel’ quanto à característica massa de fruto, e ‘Coral’ e ‘Talismã’ quanto à relação SS/AT. ‘Rubimel’ é indicada para ambiente desfavorável com relação à massa de fruto.

ABSTRACT Information on adaptability and stability of fruit production in different environments or years is crucial to increasing agricultural production potential. Therefore, the objective of this study was to evaluate whether there is interaction between cultivars and years, as well as to assess the stability of peach and nectarine cultivars regarding fruit fresh mass, SS/TA ratio, and cycle length in Viçosa -MG, Brazil. The characteristics fruit fresh mass (FM), soluble solids/titratable acidity ratio (SS/TA), and cycle length (CL) were evaluated in 28 cultivars of peach and two cultivars of nectarine from the orchard of the Universidade Federal de Viçosa, in 2011, 2012, and 2013. The methods used to determine the phenotypic stability across time were Eberhart & Russell (1966) and the Traditional. The interaction cultivars x years was significant for all traits. Cultivar ‘Josefina’ showed broad adaptability for SS/TA ratio, and cultivars ‘Flordaprince’ and ‘Tropical’ for cycle length. For favorable environments, the cultivars ‘Capdebosq’ and ‘Maciel’ are indicated regarding the characteristic fruit mass, and ‘Coral’ and ‘Talismã’ for SS/TA ratio. ‘Rubimel’ was adaptable to unfavorable environments regarding fruit mass.

RESUMO Objetivou-se com o presente trabalho avaliar a divergência genética e as características físicas e químicas de frutos de duas populações do maracujazeiro azedo na região Norte do Espírito Santo, como as progênies de meio-irmãos de acesso local de um plantio comercial (genótipos: 1; 2; 3; 4; 5; 6; 7; 8; 9 e 10) e do híbrido BRS Ouro Vermelho (genótipos: 11; 12; 13; 14; 15; 16; 17; 18; 19 e 20). A divergência genética foi avaliada por procedimentos multivariados como a distância generalizada de Mahalanobis (D2) e pelos métodos de agrupamento de otimização de Tocher e UPGMA. Encontrou-se divergência genética entre as populações estudadas promovendo a formação de grupos diferentes entre o método de Tocher e do UPGMA. As características, referentes ao tamanho do fruto, diâmetro polar e equatorial, foram as que mais contribuíram na diversidade genética dos genótipos. Nas populações estudadas de maracujazeiro azedo há grande variabilidade genética quanto às características avaliadas, o que possibilita selecionar plantas com elevado potencial para fins de melhoramento genético. O híbrido BRS Ouro Vermelho apresenta boa adaptação às condições locais.

ABSTRACT The aim of the present work was to evaluate genetic divergence and physical and chemical characteristics in fruit of two populations of sour passion fruit in the northern region of the State of Espírito Santo, Brazil, these being half-sibling progenies from local accessions of a commercial crop (genotypes 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10) and the hybrid BRS Ouro Vermelho (genotypes: 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20). Genetic divergence was evaluated using such multivariate procedures as the generalised Mahalanobis distance (D2) and the Tocher optimisation and UPGMA clustering methods. Genetic divergence was found between the populations under study, promoting the formation of different groups between the Tocher and UPGMA methods. As characteristics for fruit size, the polar and equatorial diameters had the most impact on the genetic diversity of the genotypes. In the populations of sour passion fruit being studied, great genetic variability is seen in the evaluated characteristics, making it possible to select plants of high potential for breeding purposes. The BRS Ouro Vermelho hybrid is well adapted to the local conditions.

ABSTRACT The nutritional importance of the fruit of passionfruit has prompted studies to assess its composition and antioxidant content and to evaluate it as a functional food in fresh fruit and concentrated juice markets. Currently, the use of wild species as rootstock has been recommended mainly for their positive effects such as tolerance to disease attack and maintenance of fruit quality of grafted cultivars. The aim of this study was to determine the effect of wild species of Passiflora gibertii N.E. Br. and Passiflora mucronata Lam as rootstock on the content of antioxidants and fruit quality of Passiflora edulis f. flavicarpa. The experimental design was completely randomized with four treatments and 25 replications, with a total of 100 experimental units. As a control treatment, plants of P. edulis from seed and grafted on the same species were used. Significant correlations were observed among the contents of β-carotene, ascorbic acid, luminosity values, chroma and hue angle. For the combination P. edulis/P. gibertti, the contents of β-carotene and ascorbic acid were highly correlated with luminosity, chroma and hue angle of fruit juice. A similar behavior was observed for the combination P. edulis/P. mucronata Lam. The content of β-carotene in the fruit showed no statistical differences (p < 0.05), indicating no significant rootstock effect on the variables evaluated. The results indicate a potential wild rootstock use for its positive effects on grafted plants while maintaining the commercial quality of the fruits of passionfruit crops.

RESUMO A macaúba [Acrocomia aculeata (Jacq.) Lood. ex Mart] vem sendo domesticada para subsidiar programas de produção de biodiesel no Brasil. Contudo, pouco se sabe sobre a produção de mudas desta espécie. Objetivou-se avaliar misturas de substratos, doses de calcário e de fósforo na correção do substrato e a frequência de adubação de cobertura em mudas de macaúba. Foram instalados três ensaios conduzidos em casa de vegetação, até o sexto mês de cultivo na fase de viveiro. Ensaio 1: avaliação de percentuais das frações orgânica e mineral totalizando sete misturas de substratos. Ensaio 2: avaliação de quatro doses de correção do solo com calcário versus quatro doses de fosfatagem. Ensaio 3: avaliação da frequência de fertilização com N, K e Mg em cobertura. Nos três ensaios foram observadas diferenças significativas para maioria das variáveis analisadas (altura de plantas, número de folhas, massa seca da parte aérea, massa seca da raiz, vigor e diâmetro do bulbo). Como resultados principais têm-se: Ensaio 1 - o melhor desenvolvimento das mudas é observado em substratos com pelo menos 25% de material orgânico. Ensaio 2 - doses variando de 0,50 a 1,25 kg de calcário associada à fosfatagem com 3,00 a 4,00 kg de superfosfato simples por m3 de substrato proporciona melhor desenvolvimento das mudas. Ensaio 3 - a adubação de cobertura proporciona melhor desenvolvimento das mudas independentemente da frequência.

ABSTRACT The macaw palm [Acrocomia aculeata (Jacq.) Lood. ex Mart] has been domesticated to subsidize biodiesel production programs in Brazil. However, little is known about the seedling production of this species. This study aimed to evaluate substrate mixtures, limestone and phosphorus rates for substrate amendment and topdressing frequency in macaw palm seedlings. Three trials were conducted in a greenhouse up to six months of nursery cultivation. Trial 1: determination of percent mineral and organic fractions of seven substrate mixtures. Trial 2: evaluation of four limerates for soil amendment versus four phosphorus rates. Trial 3: evaluation of N, K and Mg topdressing frequency. Significant differences were found in the three trials for most of the variables (plant height, leaf number, shoot dry mass, root dry mass, vigor and bulb diameter). The main results obtained were as follow: Trial1 - the best seedling growth was observed in substrates with at least 25% organic matter. Trial2 -lime rates ranging from 0.50 to 1.25 kg associated with 3 to 4 kg of single superphosphate per m3 of substrate provided the best seedling growth. Trial 3 - topdressing fertilization provided better development of seedlings regardless of frequency.

Os objetivos neste estudo foram avaliar os efeitos da radiação γ sobre a sobrevivência e desenvolvimento de gemas de segmentos caulinares e germinação de sementes de maracujazeiro-amarelo (Passiflora edulis f. flavicarpa) in vitro. Os explantes de segmentos caulinares (2cm) contendo uma gema axilar, obtidos a partir de plântulas provenientes da germinação in vitro de sementes de maracujá, foram tratados com raios γ em dosagens variando de 10 a 60Gy e subsequentemente transferidos para meio Murashige e Skoog (MS), suplementado com 4,0mg L-1BAP. Para a irradiação das sementes, foram testadas doses que variaram de 75-200Gy e a germinação e sobrevivência das plântulas foram avaliadas após 30 e 60 dias da inoculação em meio MS, respectivamente. Após 30 dias da irradiação de segmentos caulinares, observou-se redução de 50% na sobrevivência dos explantes e no número de brotações formadas in vitro nas doses de 21,31 e 12,20Gy, respectivamente. A DL50 para a germinação de sementes é 160Gy, enquanto que, para sobrevivência das plântulas, é de 125Gy.

This study had the objective to investigate the effects of gamma ray radiation on survival and proliferation of shoots from stem nodal segments and on the germination seeds passion fruit (Passiflora edulis f. flavicarpa). Stem segments explants (2cm) containing one axillary bud obtained from in vitro-propagated seedlings of passion fruit were treated with γ-rays at dosages ranging from 10 to 60Gy and subsequently transferred to Murashige and Skoog (MS) medium supplemented with 4.0mg L-1 BAP. Seeds of passion fruit were irradiated with gamma rays at dosages ranging from 75 to 200Gy. Germination and survival of seedlings were measured after 30 and 60 days of transfer to MS medium, respectively. After 30 days of irradiation of stem segments it was observed 50% reduction in survival of explants and the number of shoots formed in vitro at 21.31 and 12.20Gy, respectively. The LD50 for seed germination is 160Gy, while for seedling survival is 125Gy.

RESUMO A dormência de sementes é um importante mecanismo de adaptação das espécies e, geralmente, perdida durante a domesticação de plantas, devido à seleção através da coleta e plantio de sementes. Objetivou comparar a germinação e emergência de plântulas provenientes de sementes originadas de progênies autofecundadas e de polinização aberta de oito genótipos de maracujazeiro. As autopolinizações foram realizadas na fase de botão com intuito de superar a auto-incompatibilidade, e progênies de polinização aberta originadas do cruzamento natural com controle somente do genitor feminino. O experimento foi instalado no delineamento em blocos casualizados, em esquema fatorial 2 x 8 (tipo de progênies x genótipos), com quatro repetições e 50 sementes por unidade experimental. Aos 14, 21 e 28 dias da semeadura foram analisadas a porcentagem de germinação e o índice de velocidade de emergência. O comprimento total das plântulas (cm), comprimento da parte aérea (cm), comprimento da raiz (cm) e matéria seca total de plântulas (g) foram avaliados aos 28 dias de semeadura. A massa de 100 sementes (g) foi avaliada antes da semeadura. Há diferenças entre genótipo e tipo de progênie na germinação e velocidade de emergência. Verificou-se início de germinação adiantado e maior velocidade de emergência em sementes obtidas por autopolinização. Conclui-se que a dormência da semente está associada com o genótipo do embrião e que provavelmente é condicionado por um efeito genético dominante.

ABSTRACT Seed dormancy is an important adaptive mechanism in many species and is generally lost during plant domestication because of selection that occurs through the collection and planting of seeds. We compared germination and seedling emergence in selfed and open-pollinated progenies obtained from eight passion fruit vines (genotypes). Self-pollination was performed at the button stage to overcome self-incompatibility. The experiment was a randomized block design in a factorial scheme (2 x 8; type of progeny x genotypes) with four replicates and 50 seeds per experimental unit. At 14, 21 and 28 days after sowing, the germination percentage and the emergence speed index were analyzed. The total length of seedlings (cm), shoot length (cm), radicle length (cm) and total dry matter of seedlings (g) were evaluated 28 days after sowing. The mass of 100 seeds (g) was determined before sowing. Differences were noted between genotypes and progeny types with respect to germination and emergence speed. In general, seeds obtained by selfing exhibited earlier germination and a higher emergence speed. It was concluded that seed dormancy is associated with the genotype of the embryo and is most likely conditioned by a dominant genetic effect.