ABSTRACT This study was developed to carry out selection, estimate genetic parameters and predict individual genetic values of 55 genotypes from S2 families as well as estimate genetic dissimilarity based on physiological seed attributes. All S2 genotypes evaluated were obtained from self-pollination of S1 genotypes from the guava breeding program. The experiment was laid out in blocks with 55 S2 genotypes and four blocks. Genetic parameters were estimated and the best genotypes were selected based on the genetic value, using the statistical method of mixed models. In addition, genetic divergence was estimated based on the mean Euclidean distance. Although heritability values were considered medium to high magnitude for germination (0.22) and germination speed index (0.35), genetic gains were obtained for all traits. Based on the evaluation of individual BLUPs, the S2 genotypes that contributed to most of the evaluated traits were: 5, 31, 85, 214, 369, 393, 398, 442, 443, 444, 449 and 529, suggesting potential to generate vigorous. Through genetic dissimilarity, it was possible to verify the formation of five distinct groups. Therefore, the selection of divergent genotypes with high average for germination is recommended for the advancement of generation in the guava breeding plant.

ABSTRACT. The germplasm of Passiflora L. is conserved through seed banks and field collections. Dormant seeds, seeds with low viability, and high-cost field collections make it difficult to maintain germplasm banks, and in vitro conservation can be a complementary alternative. The aim of this study was to investigate the survival of nodal segments of Passiflora edulis Sims ‘UENF Rio Dourado’ over 180 days of slow growth in vitro by reducing the mineral salt and sucrose concentrations and changing the incubation conditions (temperature and light intensity). The experiment was conducted in a completely randomized design with a 2 × 3 × 3 factorial arrangement consisting of two temperatures (20 ± 2°C and 27 ± 2°C), three concentrations of MSM mineral salts (100% MSM, 50% MSM, and 25% MSM), and three sucrose concentrations (10, 20, and 30 g L-1). Evaluations were performed at 60, 90, 120, 150, and 180 days for survival, number of leaves, and plant color (using a color scale where 1 = dark green, 2 = light green, and 3 = yellow). After 180 days of culture, mineral salt, sucrose concentration, and incubation temperature affected plant survival, regeneration, and acclimatization. During the 180 days, it was possible to slow the growth of nodal segments of passion fruit ‘UENF Rio Dourado’ in culture medium with 25% MSM mineral salts plus 10 g L-1 sucrose, at an average temperature of 20°C without compromising plant survival, regeneration, and acclimatization.

ABSTRACT The use of longitudinal measurements is an essential practice both in Psidium guajava L. breeding and in other perennial crops in which covariance structures can be introduced to explain the form of dependence between measurements. Hence, this study aimed to analyze six covariance structures to identify one that best described the correlation between the repeated measurements in time in traits of guava full-sib families. The repeatability coefficient for each trait was estimated and the minimum number of evaluations required for estimates representing the population was determined. The work was performed based on average data of three yield-related variables from nine harvests of a guava tree population evaluated from 2011 to 2018. The best model was chosen based on the Akaike and Schwarz Bayesian information criterion. The autoregressive covariance structure best represented the dependencies among families between crops for all traits. The number of variables of fruits and total yield per plant presented repeatability estimates higher than 0.5 and may be essential traits for indirect selection of others, such as fruit mass, which had an estimated repeatability of 0.24, proving low regularity in the repetition of the character from one cycle to another. It was also possible to define four harvests as the minimum acceptable number of observations necessary on the same individual for these traits; therefore, the repetitions represented the individuals.

Abstract The germination potential must be considered in the selection of passion fruit genotypes, since vigorous seeds originate seedlings with a higher growth rate, resulting in superior plants with high agronomic performance. This study proposes to estimate genetic parameters and selection gain for seed traits of full-sib families (FSF) of passion fruit under recurrent selection for resistance to the cowpea aphid-borne mosaic virus (CABMV). Physical and physiological seed traits of 86 FSF were evaluated; genetic parameters, genotypic correlations between traits and genetic gains were estimated using four selection indices. There were significant differences and genetic variability between families and positive genetic correlations between variables. The best distribution of genetic gains was obtained by the Mulamba and Mock index, using the heritability coefficient and arbitrary weights. This index selected the best 26 families in terms of seed characteristics to compose the second cycle of recurrent selection for resistance to CABMV.

ABSTRACT Investigating the physiological potential of seeds and genetic divergence between families is essential to identify promising materials for the generation of improved populations. This study was undertaken to examine the germination potential and estimate genetic divergence between Passiflora full-sib families (FSFs) based on physical and physiological seed traits. The experiment was consisted of 86 FSFs from the first cycle of recurrent selection for resistance to the cowpea aphid-borne mosaic virus. Seeds were evaluated for 19 physical and physiological traits. Dissimilarity estimates were obtained by generalized Mahalanobis distance, and the method unweighted pair group method with arithmetic mean was employed for cluster formation. The FSFs showed high germination potential and seed vigor, with mean of 92.4%, 5.68 e 5.81 cm for germination, germination speed index (GSI) and shoot length of seedlings, respectively. Cluster analysis resulted in four groups formed, being Group I composed by 68 FSF more the control Passiflora edulis. The trait 1,000-seed weight (TSW) was the trait that most contributed to explaining the dissimilarity between families, with 31.9%. The trait GSI (physiological), TSW (physical), as well as traits provided by the GroundEye® system (CIELab-b, hue, and circumference of seeds), were efficient in determining genetic divergence detected between the families of passion fruit. These traits can be taken as a basis in the selection of genotypes with higher physiological seed quality.

Abstract This study intends to estimate the coefficient of repeatability for traits relating to yield, so as to infer what is the minimum number of evaluations required to identify superior genotypes; to verify adaptability and stability; to predict genetic gains; and to select the best families and in S1 progenies of Psidium guajava. Families were obtained by means of self-fertilization of superior genotypes (full sibs) from the guava tree genetic breeding program of the UENF. The experiment was implemented at the Experimental Station of Ilha Barra do Pomba, in the municipality of Itaocara-RJ. In this case, an experimental randomized block design was used with 18 inbred families, three replicates, and ten plants per plot. Inbred families were evaluated in three harvests regarding fruit weight, number of fruits per plant, and total yield. It was then conducted an analysis of repeatability, adaptability, and stability of genotypes by means of the Selegen/REML/BLUP program. Repeatability values show that the performance of genotypes is constant among measurements, suggesting the need to perform only three evaluations for the selection of superior genotypes. There was agreement on the choice of families 1, 4, 6, and 12 as the most yielded, adaptable, and stable for the traits evaluated.

Resumo O presente estudo tem por objetivo estimar o coeficiente de repetibilidade das características referentes à produção da goiabeira, a fim de inferir qual o número mínimo de avaliações é necessário para identificar genótipos superiores,inalém de verificar a adaptabilidade e a estabilidade, bem como prever os ganhosgenéticos e selecionar as melhores famílias em progênies S1 de Psidium guajava. Asfamílias foram obtidas por meio de autofecundações de genótipos superiores (irmãos-completos) doprograma de melhoramento genético de goiabeiras da UENF. O experimento foi implementadona Estação Experimental da Ilha Barra do Pomba, no município de Itaocara-RJ. Odelineamento experimental utilizado foi blocos ao acaso, com 18 famílias endogâmicas, três repetições e 10 plantas por parcela. Foram avaliadas as famílias endogâmicass em trêssafras, quanto ao peso dos frutos, ao número de frutos por planta e à produção total.Posteriormente, foi realizada a análise de repetibilidade, adaptabilidade e estabilidade dosgenótipos através do programa Selegem/REML-BLUP. Os valores de repetibilidade demonstram que o desempenho dos genótipos é constante entre as medições, indicando a necessidade de apenas três avaliações para a seleção dos genótipos superiores. Houve concordância naescolha das famílias 1;4; 6 e 12 como as mais produtivas, adaptáveis e estáveis para os caracteres avaliados.

Abstract This study was conducted to test the significance of adding row and column factors in the frequentist and Bayesian models used in the evaluation of a population of Passiflora edulis, as well as selecting promising genotypes to form the next generation. The following parameters were evaluated: number of fruits, yield, fruit weight, transverse fruit diameter, longitudinal fruit diameter, pulp percentage, skin thickness and total soluble solids. For the Bayesian model, two priors were considered, namely, inverse gamma and a priori distribution with extended parameters. The model with a priori distribution with extended parameters showed lower root mean square error and higher correlation coefficient between observed and predicted values than the inverse gamma model. Furthermore, for a selection intensity of 37%, the mixed and Bayesian models selected practically the same progenies in both experiments. The use of the 5-fold cross-validation technique indicated that both tested models were efficient.

ABSTRACT Methods for genetic improvement of semi–perennial species, such as passion fruit, often involve large areas, unbalanced data, and lack of observations. Some strategies can be applied to solve these problems. In this work, different models and approaches were tested to improve the precision of estimates of genetic evaluation models for several characteristics of the passion fruit. A randomized block design (RBD) model was compared to a posteriori correction, adding two factors to the model (post–hoc blocking Row–Col). These models were also combined with the frequentist and Bayesian approaches to identify which combination yields the most accurate results. These approaches are part of a strategic plan in a perennial plant breeding program to select promising genitors of passion to compose the next selection cycle. For Bayesian, we tested two priors, defining different values for the distribution parameters of effect variances of the model. We also performed a cross–validation test to choose a priori values and compare the frequentist and Bayesian approaches using the root mean square error (RMSE) and the correlation between the predicted and observed values, called Predictive capacity of the model (PC). The model with the post–hoc blocking Row–Col design captured the spatial variability for productivity and number of fruits, directly affecting the experimental precision. Both approaches applied to the models showed a similar performance, with predictive capacity and selective efficiency leading to the selection of the same individuals.

ABSTRACT Brazil is one of the world’s largest producers of guava (Psidium guajava L.), a very promising fruit in the northern region of the state of Rio de Janeiro. Despite this, no guava cultivar has been developed for the region. Thus, this study proposed to examine a population of guava full sibs using microsatellite markers and to identify which genotypes are the most divergent for future crosses, to select cultivars better adapted to the soil and climatic conditions of northern Rio Janeiro. Ninety-six superior genotypes were selected according to their agronomic traits, which were characterized using 45 microsatellite markers. The genetic distance between the analyzed genotypes, their clustering pattern and the genetic structure of the population were estimated. Hierarchical cluster analysis by the neighbor joining method indicated the formation of three distinct groups. The use of molecular information revealed the existence of moderate genetic variability between the genotypes of the full-sib families. Bayesian analysis separated the genotypes into only two groups, as the individuals shared most of the analyzed genomic regions. The most genetically divergent guava genotypes, that is, those allocated to different groups, such as genotypes 5 and 85, should be recommended for future crosses to obtain segregating populations, thus giving continuity to the guava breeding program.

Abstract This study analyzed the genetic diversity in Coffea canephora genotypes by univariate and multivariate statistical analysis, based on concentrations of macro- and micronu trients in coffee leaves in the stages of pre-flowering and grain filling. The experiment was arranged in randomized blocks with three replications, in a 42x2 factorial design, in which factor one represented the evaluated genotypes and factor two the periods of leaf sampling, i.e., pre-flowering and grain filling. The data of leaf nutrient concentrations were subjected to analysis of variance by the F test (p <0.01), and genetic parameters were estimated. For the study of genetic diversity, the genotypes were grouped by the hierarchical unweighted pair-group method using arithmetic averages (UPGMA). The relative importance of a trait to predict genetic diversity was also studied. There is genetic divergence for leaf nutrient concentration in C. canephora genotypes. With a maximum limit of 60% of dissimilarity between genotypes, four groups were also formed by UPGMA. For the 42 evaluated geno types, leaf S concentration was the most important trait for genetic diversity; this genotypic variability should be investigated to enhance the efficiency of nutritional diagnosis.

Resumen Este estudio analizó la diversidad genética en los genotipos de Coffea canephora mediante análisis estadístico univariado y multivariado, basado en las concentraciones de macro y micronutrientes en las hojas de café en las etapas de pre-floración y llenado de granos. El experimento se organizó en bloques aleatorios con tres repeticiones, en un diseño factorial de 42x2, donde el factor uno representaba los genotipos evaluados y el factor dos los períodos de muestreo de hojas, es decir, pre-floración y llenado de granos. Los datos de las concentraciones nutricionales de las hojas se sometieron a un análisis de varianza mediante la prueba F (p <0,01), y se estimaron los parámetros genéticos. Para el estudio de la diversidad genética, los genotipos se agruparon por el método jerárquico de pares de grupos no ponderados, utilizando medios aritméticos (UPGMA). También se ha estudiado la importancia relativa de un rasgo para predecir la diversidad genética. Existe divergencia genética para la concentración de nutrientes en las hojas en los genotipos de C. canephora. Con un límite máximo del 60% de disimilitud entre los genotipos, el método UPGMA formó cuatro grupos. Para los 42 genotipos evaluados, la concentración de S en las hojas fue la característica más importante para la diversidad genética. La variabilidad genotípica debe investigarse para mejorar la eficiencia del diagnóstico nutricional.

ABSTRACT. This research aimed to explore the reproductive characteristics of three species of Psidium (P. guajava L., P. cattleyanum Sabine, and P. guineense Sw.) and estimate a probable reproduction strategy based on the pollen:ovule (P:O) methodology. The number of pollen grains per floral bud (NGPB), number of pollen grains per anther (NGPA), number of anthers per flower bud (NAB), number of ovules per flower bud (NOB), and the P:O ratio of each species were estimated. All species had a P:O ratio over 2,000 and were classified as xenogamous. P.guajava presented the highest values for all characteristics evaluated, with the NGPB at 3,777,519, the NOB at 584.50 and a P:O ratio of 6,462.82. Similarly, P. cattleyanum had a P:O ratio of 5,649.89 (NGPB 762,736 and NOB 135). However, P. guineense was considered facultative xenogamous, with P:O of 2,085.75, the NGPB at 741,484 and the NOB at 355.50. Thus, it was concluded that the studied species have a preference for allogamy and require many pollen grains to fertilize each ovule, demonstrating that the transfer of pollen to the stigma is not very specialized.

Resumo A produção de mudas enxertadas demanda maior período de tempo. A técnica da minigarfagem sobre porta-enxertos obtidos previamente por estaquia herbácea pode garantir a fidelidade genética da copa e do porta-enxerto e possibilitar a enxertia em caules de menor diâmetro, antecipando o período de obtenção dessas mudas. O objetivo deste trabalho foi a antecipação da formação da muda da goiabeira ‘Paluma’ enxertada sobre porta-enxertos clonais com caules de menor diâmetro. Os tratamentos foram constituídos pela enxertia sobre porta-enxertos com cinco classes de diâmetros do caule. O delineamento experimental adotado foi em blocos casualizados, com três repetições e cinco mudas por parcela. Os porta-enxertos foram produzidos por estaquia de ramos herbáceos de matrizes oriundas de cruzamento entre P. guineense x P. cattleianum. Os minigarfos foram obtidos de um minijardim clonal da goiabeira ‘Paluma’. Mudas enxertadas sobre porta-enxertos com diâmetros de caule entre 3,7 e 10,3 mm tiveram a mesma taxa de pegamento de enxertia; entretanto, o maior vigor das mudas foi observado quando estas foram enxertadas sobre porta-enxertos de maior calibre. O pegamento de enxertia e a altura das mudas indicam que a minigarfagem sobre porta-enxertos clonais, com diâmetros entre 3,7 e 5,5 mm, permite a produção de mudas aptas ao transplantio, aos 300 dias após o estaqueamento.

Abstract The production of grafted seedlings requires longer periods of time. The technique of mini-grafting onto rootstocks previously obtained from herbaceous cuttings can guarantee the genetic fidelity of scion and rootstock and allows grafting onto smaller-diameter stems, accelerating the time required to obtain seedlings. The aim of this study was to anticipate the formation of ‘Paluma’ guava seedlings grafted onto clonal rootstocks with smaller-diameter stems. Treatments consisted of grafting onto rootstocks with five stem diameter classes. The experimental design was randomised blocks with three replicates and five seedlings per plot. Rootstocks were produced from cuttings of herbaceous branches of mother plants originating from crossing between P. guineense and P. cattleianum. Mini-grafts were obtained from a clonal ‘Paluma’ guava mini-garden . Seedlings grafted onto rootstocks with stem diameters from 3.7 to 10.3 mm presented the same success rate however the greatest seedling vigour was observed when grafted onto larger-diameter rootstocks. Grafting success and seedling height show that mini-grafting onto clonal rootstocks with diameters from 3.7 to 5.5 mm allows producing seedlings suitable for transplanting 300 days after cutting.

ABSTRACT Guava is of great economic importance in Brazil. The development of new cultivars by obtaining inbreeding lines has been a promising option. The objective of this work was to evaluate the S2 families of Psidium guajava using seed attributes. Different characters of physiological quality of guava seeds were studied, in addition to performing digital phenotyping of characteristics of geometry, texture and colors of the seeds. The variables were analyzed simultaneously using the Ward-Modified Location Model (MLM) method and carried out individual analyses of variance for estimating genetic parameters of the population. The formation of more than one group of divergent genotypes was observed, the geometry characteristics were more impacting for the discrimination of the genotypes, a high phenotypic correlation was observed with the germination variables and dry matter weight. High heritabilities were verified for the variables related to seed quality, indicating success in selecting vigorous genotypes. The Ward-MLM method is a useful tool to detect genetic diversity among genotypes of inbred guava. Thus, the most divergent genotypes with high germination potential can be recommended for future crosses or self-fertilized to obtain new lines in the guava breeding program.

ABSTRACT: The purpose of this study was to conduct selection, genetic parameter estimation, and prediction of genetic values for 18 S1 families of guava trees using mixed model methodology and simultaneous selection of traits by means of the additive selection index, multiplicative selection index, and mean rank adapted from Mulamba. All families analyzed were obtained by means of self-fertilization of superior genotypes (full siblings) from the genetic breeding program of guava trees at the Universidade Estadual do Norte Fluminense. An experimental randomized block design with 18 S1 families, three replicates, and ten plants per plot was used. A total of 540 genotypes (individual plants) of guava tree were evaluated. Genetic parameter estimation and selection of the best genotypes based on the genetic value were performed using the statistical procedure, from the Selegen-REML/BLUP program. The analyses of the additive selection index, multiplicative selection index, and the sum of rank adapted from Mulamba were also performed under the Selegen program. During the evaluation by the individual BLUPs, families 1, 12, 4, 6, and 8 contributed to most of the genotypes selected for the traits under evaluation, suggesting their significant potential to generate high quality and high yield genotypes. In the selection indexes via mixed models, the multiplicative index showed higher values for genetic gains (74 %), followed by the mean rank index adapted from Mulamba (19 %), and the additive index (2 %).

ABSTRACT: Multicollinearity is a very common problem in studies that employ path analysis in agronomic crops, which generates unrealistic results and erroneous interpretations. This study was aimed at assessing the path analysis in data obtained from guava tree full-sib based on modelling multiple regressions applying latent variables to neutralize the effects of multicollinearity. Seven explanatory variables were measured – fruit mass (FM), fruit length (FL), fruit diameter (FD), mesocarp thickness (MT), peel thickness (PT), pulp mass (PM), total number of fruits (NTF) –, plus the main dependent variable, total yield per plant (YIELD). In accordance with the multicollinearity scenario, eleven values were tested with the addition of the constant K to the diagonal of the correlation matrix X’X. Path analysis was applied in two models: all the explanatory variables with direct effect on the dependent one and another model with multiple regression with more than one chain and the presence of latent variables. The path analysis in the multivariate methodology of structural equation modelling (SEM), which uses latent variable prediction, provided better results than the traditional and ridge path analyses.