Allelic database and divergence among Psidium accessions by using microsatellite markers.

Area of Science:

• Plant genetics
• Agricultural science
• Molecular biology

Background:

• Guava (Psidium guajava) is an important fruit crop with diverse germplasm.
• Understanding genetic variability is crucial for effective breeding and conservation efforts.
• The Embrapa Semiárido collection houses valuable guava and related Psidium species.

Purpose of the Study:

• To assess genetic diversity within guava accessions and wild Psidium species.
• To guide genetic resource management and breeding strategies, particularly for interspecies crosses.
• To inform conservation efforts by identifying patterns of genetic diversity distribution.

Main Methods:

• DNA extraction using the CTAB method.
• Microsatellite marker analysis with polymerase chain reaction (PCR).
• Genetic similarity analysis using Jaccard coefficient, UPGMA dendrogram, and Analysis of Molecular Variance (AMOVA).

Main Results:

• High genetic variability (ΦST = 0.238) was observed among accessions.
• Five distinct genetic groups were identified, including guava, P. guineense, P. friedrichsthalianum, and P. cattleianum.
• Significant genetic similarity (>80%) between P. guineense and some guava accessions suggests potential for interspecies hybridization.

Conclusions:

• The study highlights substantial genetic diversity within the analyzed Psidium collection.
• P. guineense presents a promising source for interspecies hybridization with guava.
• Recommendations include expanding accession collection across Brazilian states to capture broader genetic diversity.