Relationship Between Ecogeographic Sampling and Phenotypic Diversity of Brazilian Psidium Germplasm Based on Categorical Descriptors

Abstract

Relationships between eco-geographic origin and phenotypic variation were established for 143 Psidium accessions, including "araçá" (a general term for wildgrowing Psidium spp. in Brazil) and guava (P. guajava) species, sampled in 31 different eco-geographic regions of ten Brazilian States. The accessions were characterized for 35 categorical traits according to the International Union for the Protection of New Varieties of Plants (UPOV) descriptors for P. guajava. The correlation between the cophenetic values and the simple matching matrices was 0.55, and the badness-of-fit of the multidimensional scaling was 0.30. Eighty-eight percent of the araçá accessions were grouped together and they clustered according to ecogeographic regions. Clusters of guava accessions were verified only in collections from four Brazilian States, and did not present clustering by specific ecogeographic regions. It was expected that the capturing of rare alleles and the enhancement of the genetic variability of Psidium germplasm could be achieved by sampling accessions according to predefined geographical areas, even for guava germplasm.

Development of single nucleotide polymorphism markers and genetic diversity in guava (Psidium guajava L.)

“…Previous molecular studies of Mexican guava germplasm have reported the lack of association between genetic grouping and geographical origin, mostly when including only local germplasm (Hernández‐Delgado et al, 2007; Sánchez‐Teyer et al, 2010). Likewise, associations between geographic origin and phenotypic diversity in Brazilian germplasm have not been observed (Fernandes‐Santos et al, 2010). Only a few studies have included accessions from different countries, in which case, there are clearer relationships between genetic diversity and geographic origin (Mehmood et al, 2016).…”

“…The lack of molecular resources has limited genetic diversity studies in guava. Only a handful of diversity surveys have been conducted using low‐density marker panels, and these studies have generally been unable to reconstruct perceived associations between genetic, phenotypic diversity, and ecogeographic origin in Mexican (Sánchez‐Teyer et al, 2010), Brazilian (Fernandes‐Santos et al, 2010), and Pakistani guava germplasm (Mehmood et al, 2014). Few comprehensive studies have explored the global genetic diversity and differentiation of guava germplasm, although it undoubtedly exists (Mehmood et al, 2014).…”