Genetic structure of apple accessions maintained ex situ in Bosnia and Herzegovina examined by microsatellite markers

Abstract

In order to identify possible mislabeling of the apple accession maintained ex situ in Srebrenik and to gain insight into the genetic structure of the conserved germplasm, 14 accessions from the collection were genotyped using 10 SSR (Simple Sequence Repeats) markers. Obtained SSR profiles were then added to an existing database constructed for previously characterized 24 traditional and 13 international, reference apple cultivars maintained at the same collection. Bayesian analysis implemented in the STRUCTURE program grouped 42 out of 51 analyzed apple accessions (38 traditional and 13 international) into three RPPs (reconstructed panmictic populations) with probability of membership qI higher than 75%. Almost all international, reference cultivars grouped in RPP3, whereas traditional B&H cultivars from the Srebrenik collection grouped in all three RPPs. Large and significant differentiations between all three individual RPPs were detected through the analyses of molecular variance and confirmed with FCA (factorial correspondence analyses). NJ cluster analysis, based on the Bruvo genetic distance, revealed that out of 38 traditional B&H apple cultivars, analyzed in the study, 'Ljepocvjetka', 'Bobovec' and 'Bobovec J' grouped closest to the international reference cultivars. Available date indicates that unlike a large number of B&H apple cultivars which were introduced during the reign of the Ottoman Empire, 'Ljepocvjetka' and 'Bobovec' were probably introduced at a later date. Cluster analyses also enabled the detection of one synonym and three homonyms within the collection. In four cases, previously conducted identification based on phenotypic analyses was confirmed by genetic analyses. Results of the structure analyses indicate a heterogeneous genetic structure of the analyzed accessions. This characteristic of the B&H apple germplasm could be useful for future breeding programs.

U cilju sticanja uvida u genetsku strukturu germplazme jabuke održavane ex situ u Srebreniku, 14 aksešna iz date kolekcije genotipizirano je korišćenjem 10 SSR markera. Dobijeni SSR profili dodati su već postojećoj bazi podataka sačinjenoj od prethodno karakteriziranih 24 tradicionalnih i 13 internacionalnih, referentnih sorti koji se održavaju u istoj kolekciji. Bayesian analiza sprovedena u STUCTURE računarskom programu grupisala je 42 od 51 analiziranog aksešna jabuke (38 tradicionalnih i 13 internacionalnih) u tri RPP-a (rekonstruisane panmiktičke populacije) sa verovatnoćom članstva ql veće od 75%. Gotovo sve internacionalne, referentne sorte grupisale su se u RPP3, dok se tradicionalne BiH sorte iz Srebrenika mogu naći u sva tri RPP-a. Visoka i statistički značajna diferencijacija uočena je između pojedinačnih RPP-ova i dodatno potvrđena sa FCA (faktorska korespondentna analiza). NJ klaster analiza, bazirana na Bruvo genetskoj udaljenosti, otkrila je da od 38 ispitivanih tradicionalnih BiH sorti jabuke, 'Ljepocvjetka', 'Bobovec' i 'Bobovec J.' se grupišu najbliže internacionalnim, referentnim sortama. Dostupni podaci ukazuju da za razliku od velikog broja BiH sorti jabuke koje su introdukovane tokom vladavine Osmanskog carstva, 'Ljepocvjetka' i 'Bobovec' su verovatno introdukovane na ove prostore nešto kasnije. Klaster analiza je takođe omogućila detekciju jednog sinonima i tri homonima unutar kolekcije. U četiri slučaja, prethodno sprovedena identifikacija na osnovu fenotipa je potvrđena genetskim analizama. Rezultati analize genetske strukture ukazuju na heterogenu strukturu analiziranih aksešna. Ova karakteristika BiH germplazme jabuke može biti interesantna za buduće oplemenjivačke programe.