Molecular characterization of guava Psidium guajava in Cereté, Córdoba, Colombia

Abstract

Guava (Psidium guajava L.) is the most cherished cultivated fruit species in the Myrtaceae family, and it is a perennial tree native to tropical America. The objective of this study was to determine the genetic variability of Psidium guajava in Cereté (Colombia) using SSR markers. DNA extraction was performed using the Mini-prep method with modifications. Nine microsatellites were amplified using the PCR Touchdown technique. Genetic-population parameters such as the number of alleles, effective number of alleles, observed heterozygosity, expected heterozygosity, fixation index, Hardy-Weinberg equilibrium, and polymorphic information content were calculated using PopGene 1.31 software. The number of alleles varied between 4 for markers mPgCIR13, mPgCIR20, mPgCIR23, and 8 for marker mPgCIR19, respectively. The average value of effective number of alleles was 3.722, observed heterozygosity was 0.217, and expected heterozygosity was 0.254. The average fixation index was 0.101. Hardy-Weinberg equilibrium tests revealed significant differences in the markers. The FIS coefficient had an average value of 0.385, the FIT coefficient showed an average of 0.490, and the FST coefficient had a value of 0.178. Genetic distance analysis showed that Mateo Gómez was closely related to Retiro de los Indios, while Rabolargo appeared to be the most distant population. The study revealed low genetic variability within and between the populations studied, possibly, reflecting the type of asexual propagation applied in guava crops.