Genetic structure of a worldwide germplasm collection of Prunus armeniaca L. reveals three major diffusion routes for the varieties issued from the species’ centre of origin

Authors: BOURGUIBA, HEDIA - University Of Tunis El Manar; SCOTTI, IVAN - Inland Northwest Research Alliance, Inra; SAUVAGE, CHRISTOPHER - Consultant; ZHEBENTVAEVA, TATIANA - Clemson University; Ledbetter, Craig; KRSKA, BORIS - Mendel University; REMAY, ARNAUD - Biogeves; D'ONOFRIO, CLAUDIO - University Of Pisa; IKETANI, HIROYUKI - National Agricultural Research Organization - Japan (NARO); CHRISTEN, DANILO - Agroscope; KRICHEN, LAMIA - University Of Tunis El Manar; TRIFI-FARAH, NEILA - University Of Tunis El Manar; LIU, WEISHENG - Liaoning Research Institute Of Pomology; ROCH, GUILLAUME - Cep Innovation; AUDERGON, JEAN-MARC - Inra, Génétique Animale Et Biologie Intégrative , Jouy-En-josas, France

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2020
Publication Date: 5/25/2020
Citation: Bourguiba, H., Scotti, I., Sauvage, C., Zhebentvaeva, T., Ledbetter, C.A., Krska, B., Remay, A., D'Onofrio, C., Iketani, H., Christen, D., Krichen, L., Trifi-Farah, N., Liu, W., Roch, G., Audergon, J. 2020. Genetic structure of a worldwide germplasm collection of Prunus armeniaca L. reveals three major diffusion routes for the varieties issued from the species’ centre of origin. Frontiers in Plant Science. https://doi.org/10.3389/fpls.2020.00638.
DOI: https://doi.org/10.3389/fpls.2020.00638

Interpretive Summary: Apricot is an important crop with nearly 600,000 hectares under production worldwide for fresh and dry fruit consumption as well as for many industrial products. This perennial crop grows on six of the world’s seven continents and has its center of origin in China and Central Asia. Throughout many times in history, apricot has been dispersed to distant geographical regions intentionally, and through human intervention and selection, new forms were developed and propagated for their superior attributes. These routes of dispersion were investigated through the sampling of nearly 900 apricot accessions that were selected and developed in the world’s different apricot growing regions. Microsatellite markers were applied to the sampled apricots to examine the genetic diversity among the many accessions. Analyzed data from the marker set revealed five major clusters that corresponded closely with the different geographic regions from which the apricots were developed. The highest level of genetic diversity was confirmed among apricot accessions from China and Central Asia, and a gradient of lower genetic diversity was observed in apricots developed in regions distant from the center of origin. These results provide an opportunity to identify genomic regions of apricot that are associated with site-specific quality attributes as well as for identifying efficient accessions for a core germplasm collection that represent the extent of apricot diversity.

Technical Abstract: The characterization of the largest worldwide representative data set of apricot (Prunus armeniaca L.) germplasm was performed using molecular markers with the aim to analyze the patterns of genetic diversity and structure of the cultivated apricot genetic resources and to decipher the history of diffusion and use of this species around the world. A common set of 25 microsatellite markers was applied to genotype a total of 890 apricot accessions across different collections from the centre of origin to the more recent regions of apricot culture. A Bayesian model-based clustering approach showed that diversity was organized in five differentiated genetic clusters (FST = 0.174), with a clear association with the apricot accessions geographical regions of origin. Accessions from China and Central Asia were clustered together and enclosed the highest levels of diversity, confirming an origin in this region. A loss of genetic diversity was observed from the centre of origin to both western and eastern zones of recent apricot culture. Altogether, our results revealed that apricot spread from China and Central Asia, defined as the centre of origin, following three major diffusion routes with a decreasing gradient of genetic variation in all the phylums. The present work thus constitutes a decisive step in the understanding of the worldwide history of diffusion of apricot as well as in the field of conservation of available genetic resources. The data offer an objective opportunity for defining an apricot core collection useful for further identification of genomic regions associated with commercially important horticultural traits through genome-wide association studies to sustain apricot breeding programs.