Molecular and quantitative genetic analysis of the neotropical tree Campomanesia xanthocarpa (Mart.) O. Berg.

Abstract

Campomanesia xanthocarpa is a fruit tree species of the Myrtaceae family with potential for fruit commercialization; however, studies on the genetic diversity and variability of the species are necessary to make it commercially viable. The objective of this study was to characterize the diversity and intrapopulation spatial genetic structure (SGS) of a C. xanthocarpa population and compare the genetic parameters of quantitative traits between and within open-pollinated progenies. For the analysis of genetic diversity, 80 individuals from a population in the Irati National Forest, Parana, Brazil, were analyzed. The observed (Ho) and expected (He) heterozygosity, fixation index (F), and intrapopulation spatial genetic structure (SGS) were assessed. To analyze the quantitative traits, a field progeny test was installed using a randomized block design with nine progenies, three blocks, and four plants per plot at a spacing of 9 m². Total height (H), basal diameter (dbase), crown length and diameter (Ccrown and dcrown) at two years and nine months of age were measured. For the studied population, Ho and He had an average of 0.478 and 0.717, respectively, with an average fixation index of 0.333, suggesting that the population may be suffering from inbreeding. We found linkage disequilibrium for one evaluated pair of loci. SGS suggested a minimum distance of 25 to 50 m between mother trees for seed collection. For the quantitative genetic analyses, we found that average heritability ranged of 0.15 to 0.55 being considered from moderate (dbase) to high (H, Ccrown and dcrown). The traits H and dcrown were particularly noteworthy and can be used to obtain superior genotypes for the other traits (dbase and Ccrown), since the correlation was significant and high (> 0.80). The results provide applicable information for the implementation of breeding and conservation programs for the species.