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 %).

Resumo: O objetivo deste trabalho foi estimar os parâmetros genéticos e avaliar as associações entre características vegetativas e de produção em progênies de irmãos completos de goiabeira (Psidium guajava). Avaliaram-se as seguintes características: produção por planta, número de frutos, massa de frutos, altura da planta, diâmetro de caule e volume de copa. A estimativa de parâmetros genéticos foi obtida com o procedimento REML/Blup. Com base nos valores genéticos preditos pelo Blup, estimaram-se as correlações genéticas e canônicas, e realizou-se o desdobramento dos coeficientes de correlação genética em efeitos diretos e indiretos sobre a característica produção por planta, com análise de trilha. Estimou-se variabilidade genética para número de frutos (567,66) e produção por planta (11,818), com alta correlação genética (0,9045), o que evidencia seleção simultânea. A seleção indireta não promoveu ganhos simultâneos para produção por planta a partir dos componentes primários número de frutos e massa de frutos, o que dificulta a obtenção de cultivares de goiabeira com alta produção, número de frutos e massa de fruto. As características vegetativas apresentaram pouca influência na produção, no número de frutos e na massa de frutos.

Abstract: The objective of this work was to estimate the genetic parameters and to evaluate the associations between vegetative and yield characteristics, in full-sib progenies of guava tree (Psidium guajava). The following characteristics were evaluated: yield per plant, number of fruits, fruit mass, plant height, stem diameter, and canopy volume. The estimation of genetic parameters was obtained by the REML/Blup procedure. Based on the breeding values predicted by Blup, the genetic and canonical correlations were estimated, and the genetic correlation coefficients were unfolded into direct and indirect effects on the character yield per plant using path analysis. Genetic variability was estimated for number of fruits (567.66) and yield per plant (11.818), with high genetic correlation (0.9045), indicating simultaneous selection. Indirect selection did not promote simultaneous gains for yield per plant with the primary components number of fruits and fruit mass, making it difficult to obtain guava cultivars with high yield, number of fruits, and fruit mass. The vegetative traits had little effect on yield, number of fruits, and fruit mass.