Allelic database and divergence among Psidium accessions by using microsatellite markers

Abstract

ABSTRACT. This study aimed to investigate the genetic variability among guava accessions and wild Psidium species of the Embrapa Semiárido germplasm collection by using microsatellite loci to guide genetic resources and breeding programs, emphasizing crosses between guava and other Psidium species. DNA was extracted using the 2X CTAB method, and polymerase chain reaction products were analyzed on 6% denatured polyacrylamide gels stained with silver nitrate. The unweighted pair-group method using arithmetic average dendrogram generated from the distance matrix of the Jaccard coefficient for 183 alleles of 13 microsatellite loci was used for visualization of genetic similarity. The number of base pairs was estimated using inverse mobility method based on the regression of known-size products. Analysis of molecular variance was performed using total decomposition between and within guava accessions. The accessions showed similarity from 0.75 to 1.00, with the dendrogram presenting cophenetic value of 0.85. Five groups were observed: the first included guava accessions; the second, P. guineense accessions; the third, one accession of P. friedrichsthalianum; and the last 2 groups, P. cattleianum. The genetic similarity among P. SSR Psidium allelic database and accession divergence guineense and some guava accessions were above 80%, suggesting greater possibility to obtain interspecies hybrids between these 2 species. The genetic variability between the accessions was considered to be high (Φ ST = 0.238), indicating that guava genetic variability is not uniformly distributed among the 9 Brazilian states from where the accession were obtained. Obtaining a greater number of accessions by Brazilian states is recommended in order to have greater diversity among the species.

Genetic divergence among Psidium accessions based on single nucleotide polymorphisms developed for Eucalyptus

“…The largest number of accessions were clustered in group I, comprising 44 of the 53 accessions, formed exclusively by guava accessions. The same grouping pattern was observed by da Costa and Santos (2013) based on microsatellite markers and Briceño et al (2010) among Venezuelan accessions of guava and other species of Psidium such as P. guineense. The highest similarity (100%) was observed among the accessions GUA62BA and GUA109RS collected in different regions, Antonio Gonçalves, BA, and Pelotas, RS, respectively.…”

“…The similarity among accessions ranged from 0.58 to 1.00 reflecting the existence of high genetic variability among studied accessions. High genetic variability was also reported by da Costa and Santos (2013) among the 61 Psidium accessions of that same collection evaluated by microsatellite marker. Corrêa et al (2011) also reported high genetic variability among 88 Psidium accessions, with similarities ranging from 0.28 to 0.98 based on AFLP markers.…”

“…DNA was extracted according to the method proposed by Doyle and Doyle (1990) with modifications as described by da Costa and Santos (2013). The DNA was quantified on 0.8% agarose gel stained with ethidium bromide by visually comparing the intensity of the DNA bands extracted with those of bands of Lambda phage DNA.…”

“…The amplification program consisted of denaturation of the initial cycle at 94°C for 4 min; 37 cycles at 94°C for 45 s, 54°C for 60 s, and 72°C for 60 s; and one stage of final extension at 72°C for 5 min. Amplified PCR products were separated on 6% polyacrylamide gels as described by da Costa and Santos (2013).…”

“…Valdés-Infante et al (2007) reported the characterization of guava accessions of Cuban origin with microsatellites. da Costa and Santos (2013), in a study of four Psidium species, comprising 61 accessions, reported similarity between P. guajava and P. guineense of 82.4% through SSR markers. Kidaha et al (2014) characterized 58 guava cultivars in Kenya through SSR and ISSR markers.…”