Variability and genetic structure of yellow passion fruit (Passiflora edulis f. flavicarpa Degener) in Colombia using microsatellite DNA markers

Abstract

Colombia is one of the leading producers of yellow passion fruit but the genetic studies based on molecular markers from commercial plantations have not been considered to select interesting market material. The goal of this study was to assess the genetic variability and the population structure of 51 Colombian commercial yellow passion fruit accessions (102 individuals), and to provide the necessary information for prospective selection and breeding programs. Thus, a total of six microsatellites were amplified with 58 alleles identified and an average of 9.66 alleles per locus, including nine private and 31 rare. Diversity indexes showed polymorphic information content values of 0.74 (PIC), an observed (Ho) and expected (He) heterozygosity average of 0.52 and 0.78, respectively. Spatial distribution showed the greatest allelic richness (11 to 14) in most of the Valle del Cauca accessions. The average genetic distance among accessions was 0.68, and the cluster analysis showed three main groups poorly supported (bootstrap <50%), with slight geographical structure and high differentiation between individuals of the same accession. Structure analysis indicated K=4 as the genetic structure's uppermost hierarchical level, while Bayesian clustering showed a division of individuals into four genetically distinct groups. The low geographic structure and high variability of the accessions could be explained by allogamy and seed exchange frequency among farmers. Results issued suggest a complementary agro-morphological assessment to establish total genetic variability and implement a breeding program through assisted selection of superior genotypes in search of more productive and resistant cultivars to phytosanitary problems.

Characterization of the genetic diversity in Passiflora spp. in the Boyacá Department, Colombia

“…The average value of Nei-Li genetic diversity was 0.40, consistent with that expected for cross-pollinated species and with the values observed in studies on genetic diversity in Passiflora (Santos et al, 2011;Oluoch et al, 2018;Oliveira et al, 2019;Vianna et al, 2019). Ocampo et al (2017), when evaluating the diversity and genetic structure of P. edulis f. flavicarpa in Colombia with microsatellites, found an average genetic distance of 0.683 and that the structuring of the groups was not consolidated and could vary, just as in this study it was observed that the internal branches of the dendrogram were moderately compatible (bootstrap ≥ 50%) and ratified the grouping between some materials of the same department. The relationship between individuals of the same species was low and did not present a geographical pattern according to the origin of each material.…”

“…The AMOVA showed that 64% of the variation observed in the evaluated Passiflora materials was explained by the component within the groups, and 36% was explained by the differentiation between the groups, so it is necessary to consider subdivision levels and hierarchy greater than those contemplated in this study, in addition to the high levels of variation at the intraspecific level, which should be used for management and conservation strategies of this plant genetic resource (Table 4), which has also been reported in other genetic diversity studies on Passiflora using this marker (Ocampo et al, 2017;Oluoch et al, 2018;Fonseca-Trujillo et al, 2019). In interspecific analyses, a higher polymorphism rate in combination with a higher average number of bands amplified per primer is indicative of high genetic diversity (Cerqueira-Silva et al, 2012).…”

“…The similarity rates were not so high since they are allogamous species, with sexual reproduction preferred, so there was manifest variability with no consistent formation of groups in terms of geographical origin or species, but there was lax distribution of the materials in terms of the evaluated municipalities, with inter-and intraspecific variability that can be used to obtain new planting materials. The lack of group structuring according to the geographical origin or species probably derive from the self-incompatibility found in most Passiflora species and the cross-pollination (Ocampo et al, 2017). The presence of exotic species such as gulupa or curuba also made a great contribution to the total genetic diversity observed in each group (Figure 2).…”

“…Despite the productive potential, a limiting factor in the development of this crop in Colombia is the incidence of pests and diseases, generating significant losses in yield (Ocampo et al, 2013). On the other hand, there is a need for breeding programs that offer cultivars with higher genetic and phytosanitary quality that respond to the needs of farmers (Ocampo et al, 2017).…”

“…Other research conducted in Colombian on P. ligularis accessions (sweet granadilla) suggests that the cultivated germplasm has high variability (He = 0.96), with a slight genetic structure (Bernal et al, 2014). Ocampo et al (2017) studied the genetic diversity and population structure of 51 Colombian passion fruit accessions (P. edulis Sims f. flavicarpa O. Deg.)…”