The REML/BLUP procedure has been successfully used for genetic progress through individual selection of high-yielding passion fruit genotypes resistant to the Cowpea aphid-borne mosaic virus. This study was thus developed to estimate genetic parameters and predict the gain obtained from individual selection of genotypes in a population derived from backcrosses in passion fruit. The experiment was set up as a randomized block design with four replicates, involving fi ve full-sib families (genotypes from the fi rst backcross). Variance components and the genetic values were estimated for eight agronomic traits via the REML/BLUP procedure. For all traits, genotypic variance between the genotypes from the fi rst backcross showed little contribution to the phenotypic variance. The low heritability estimates obtained for the traits are overcome via individual BLUP estimates. Therefore, it was possible to obtain considerable gains with individual selection for the variables fruit length, average fruit weight, and pulp weight (19.50 to 14.04%; 22.93 to 17.97%; and 10.08 to 7.95%, respectively). For the traits showing lower gains, it is possible to obtain gains indirectly by selecting genotypes for correlated traits. Because this population derives from the fi rst backcross generation, agronomic traits still must be recovered.

The purpose of this study was to conduct selection, genetic parameter estimation, and prediction of genetic values for 18 S 1 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 S 1 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 %).

In passion-fruit breeding programs, characterizing genotypes developed through morpho-agronomic descriptors helps quantify genetic diversity and identify individuals with desirable qualities. We examined the discriminatory ability of passion-fruit descriptors and determined their relative importance in the characterization of 91 genotypes from a breeding program for resistance to Cowpea aphid-borne mosaic virus. Twenty-four quantitative and 14 multi-category qualitative descriptors related to plant, leaf, flower, and fruit characteristics were used. The quantitative descriptors were subjected to correlation and principalcomponent analyses and selected based on direct selection and the Singh method. The traits were used to obtain a distance matrix, based on Gower's algorithm, and a comparative clustering between the dendrograms for the morpho-agronomic variables was obtained using the unweighted pair group method with arithmetic mean procedure. Based on the principal components method, the traits that most contributed to genetic variability were number of seeds (23.241%), petiole length (19.438%), and petal width (10.440%). In its turn by the Singh method, the traits androgynophore length (6.68%), ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 18 (2): gmr18255 V.O. dos Santos et al. 2followed by flower length (5.47%), area under the disease progress curve (5.27%), and peduncle length (5.17%) were those which most contributed to the differentiation of genotypes. Although seven descriptors (leaf length, bract width, corona long filament length, sepal length, fruit width, fruit mass, and mass of fruit pulp) showed little contribution to the characterization of genotypes, their discard is not suggested, as they significantly contribute to the discrimination of genetic divergence in the population. Comparative analysis between the dendrogram containing all descriptors and the dendrogram containing only flower, leaf, or fruit descriptors evidenced the need for using a large number of descriptors in the characterization of genetic diversity in Passiflora. The use of all 38 descriptors increased the efficiency in the discrimination of groups.

The woodiness disease induced by the Cowpea aphidborne mosaic virus (CABMV) is regarded as a limiting factor for passion fruit production. We estimated genetic parameters for resistance and agronomic performance-related traits and selected genotypes resistant to CABMV in segregating populations of passion fruit. The experiment was a randomized-block design with four replicates, consisting of six full-sibling first backcross genotype families, in which 319 genotypes were evaluated. The disease symptoms were evaluated based on spontaneous occurrence of CABMV, using a scale of scores in young leaves, plant and fruits. Based on these scores, we estimated the area under the disease progress curve (MAUDPC). Agronomic traits were also assessed: fruit weight per plant and number of fruits per plant. The variance components and genetic value of each genotype were estimated for each variable via mixed models. The MAUDPC values ranged from 401.25 to 1192.5, indicating considerable genetic variability. The high individual narrow-sense heritability value for the MAUDPC trait (0.95) indicates the possibility of genotypic selection within CABMV-resistant families. For the production-related traits, even ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 20 (1): gmr18668 S.C. Preisigke et al. 2 with low heritability values, it was possible to obtain genetic gains in individual selection, which ranged from 4.99 to 6.24% for fruit weight and 22.64 to 28.70% for number of fruits. The genotypes chosen to compose the next backcross generation should be selected based on resistance to CABMV, which is the main objective of the program, since agronomic traits can be recovered from backcrosses. Of the 30 individuals ranked for CABMV tolerance, genotypes 501, 506, and 597 were selected to compose the next generation of backcrosses. These had the lowest values for MAUDPC.

The use of several strategies for estimating genetic parameters in passion fruit (Passiflora spp.) segregating populations has important implications for understanding the nature of variances, especially the traits of resistance to collar rot. The objective of this study was to estimate genetic parameters and predict gains with the selection of genotypes resistant to collar rot in a population of interspecific passion fruit hybrids. For the analysis of restricted maximum likelihood/ best linear unbiased prediction (REML/BLUP), 40 interspecific hybrids obtained by crossing resistant wild species with Passiflora edulis Sims genotypes were analyzed. The Comstock and Robinson Design II methodology used two male parents (P. nitida Kunth and P. quadrangularis L.) and two female parents of P. edulis. The evaluations took place for 33 d and 10 variables of resistance to collar rot were characterized. The expression of most variables was due to the genetic effect. Dominance effects predominated. High estimates of heritability based on clone average and selective accuracy were observed, which provides favorable gains in reducing the severity of collar rot by selecting the genotypes 115-5,