Recurrent selection in Passiflora: a new approach for the development of cowpea aphid-borne mosaic virus resistant cultivars with desired agronomic traits.

Among the diseases that affect passion fruit (Passiflora edulis Sims), fruit woodiness is considered the most economically important viral disease of the crop, causing great production losses worldwide. This study was developed to estimate the genetic parameters for resistance and agronomic performance, using the REML/BLUP (Restricted Maximum Likelihood/Best Unbiased Linear Prediction) procedure; and compare predicted genetic gains for resistance and agronomic traits, using five selection-index approaches, to determine the most appropriate method for reliably selecting superior genotypes for a new cycle of recurrent selection aimed at effectively increasing the concentration of favorable alleles in the population. The experiment was carried out in the municipality of Campos dos Goytacazes, Rio de Janeiro, Brazil, in a randomized block design consisting of 90 full-sib families (constituting the C₀ population of recurrent selection), involving three replicates with three plants per plot. The following variables were evaluated: mean area under the disease progress curve, number of fruits per plant, total production per plant, fruit length, fruit diameter, average fruit weight, pulp weight, mesocarp thickness, soluble solids content, and pulp yield. Simultaneous selection of superior genotypes was carried out by the selection index approach using the Mulamba and Mock rank-sum index; the additive index; the multiplicative index; the mean rank index adapted from Mulamba and Mock; and the combined selection index. The additive index was the most consistent for the combined selection of the 36 genotypes for the evaluated traits, especially resistance, showing that these genotypes have high genetic potential to form the next population. [ABSTRACT FROM AUTHOR]