Generating relevant information for breeding Passiflora edulis: genetic parameters and population structure

Abstract

Passion fruit is an economically important tropical fruit crop with unrealized genetic potential. This study aimed to provide breeders with essential estimates of genetic parameters and of the structure of a typical breeding population. To achieve this, eighty-one progenies derived from the third cycle of recurrent selection were assessed for eight fruit yield and quality traits. First, we evaluated the efficiency of the post hoc implementation of a Row–Col design for data analysis instead of the original randomized complete block design (RCBD). Next, we applied a restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) mixed model to estimate genetic parameters: variance components, heritability, and genetic correlations. The population genetic structure was evaluated using 10 simple sequence repeat (SSR) markers. Results indicate that the post hoc blocking fit the data significantly better or equally to the RCBD. Soluble solids content showed the highest heritability value (0.53 ± 0.087) while yield presented the lowest estimate (0.24 ± 0.090). The 10 SSR loci amplified a total of 29 alleles revealing that the progenies evaluated could be divided into three groups. This grouping information can be used to direct future crosses of this population to maximize heterosis for the traits of interest. Correlations among variables indicate that the number of fruit can be used as a proxy for yield. Future population evaluation studies should consider incomplete block designs to maximize the land and labor resources.