Multivariate analysis to quantify genetic diversity and family selection in sour passion fruit under recurrent selection

Brazil is one of the world’s leading producers of sour passion fruit (Passiflora edulis Sims), a specie with high genetic variability. This variability can be exploited in breeding programs to develop cultivars with high yield potential and resistant to biotic and abiotic stress. The aim of the present study was to quantify the genetic divergence in families of full-sibs of sour passion fruit and to select families for a new recurrent selection cycle. Thirty-five families of sour passion fruit in the second cycle of recurrent selection were evaluated. Thirty quantitative descriptors and thirteen qualitative descriptors were measured. Molecular information was obtained using 21 ISSR markers. The data were evaluated through multivariate analysis, using the Ward-MLM procedure. The thirty-five families showed high genetic variability. Four groups were formed, with genetic distances ranging from 267.99 to 4220.00. The greatest dissimilarities between families within groups were observed in group III. The 20, 15, 10 and 5 families with the greatest dissimilarities were selected for recombination in a new recurrent selection cycle. Genetic variability was affected by the number of selected families. The greater the intensity of selection applied, the greater the loss of alleles and the more intense the reduction of the Nei and Shannon indices. The quantification of the population’s genetic diversity by multivariate analysis was efficiently performed, providing enough information for selection based on genetic distance. For a new selection cycle, the greater the number of selected families, the less the genetic variability is or was affected.