Evidence of an additional centre of apple domestication in Iran, with contributions from the Caucasian crab apple Malus orientalis Uglitzk. to the cultivated apple gene pool.

Divergence processes in crop-wild fruit tree complexes in pivotal regions for plant domestication such as the Caucasus and Iran remain little studied. We investigated anthropogenic and natural divergence processes in apples in these regions using 26 microsatellite markers amplified in 550 wild and cultivated samples. We found two genetically distinct cultivated populations in Iran that are differentiated from Malus domestica, the standard cultivated apple worldwide. Coalescent-based inferences showed that these two cultivated populations originated from specific domestication events of Malus orientalis in Iran. We found evidence of substantial wild-crop and crop-crop gene flow in the Caucasus and Iran, as has been described in apple in Europe. In addition, we identified seven genetically differentiated populations of wild apple (M. orientalis), not introgressed by the cultivated apple. Niche modelling combined with genetic diversity estimates indicated that these wild populations likely resulted from range changes during past glaciations. This study identifies Iran as a key region in the domestication of apple and M. orientalis as an additional contributor to the cultivated apple gene pool. Domestication of the apple tree therefore involved multiple origins of domestication in different geographic locations and substantial crop-wild hybridization, as found in other fruit trees. This study also highlights the impact of climate change on the natural divergence of a wild fruit tree and provides a starting point for apple conservation and breeding programmes in the Caucasus and Iran.

Beauty will save the world, but will the world save beauty? The case of the highly endangered Vavilovia formosa (Stev.) Fed.

MAIN CONCLUSION: Vavilovia formosa (Stev.) Fed. is a scientifically valuable common ancestor of the plant tribe Fabeae and also important in breeding and agronomy studies of the cultivated Fabeae, but it is close to extinction. A concerted academic and geovernmental effort is needed to save it. Since 2007, an informal international group of researchers on legumes has been working to increase awareness of Vavilovia formosa (Stev.) Fed., a relict and endangered wild-land relative to crop plant species. A majority of the modern botanical classifications place it within the tribe Fabeae, together with the genera vetchling (Lathyrus L.), lentil (Lens Mill.), pea (Pisum L.) and vetch (Vicia L.). V. formosa is encountered at altitudes from 1,500 m up to 3,500 m in Armenia, Azerbaijan, Georgia, Iran, Iraq, Lebanon, Russia, Syria and Turkey. This species may be of extraordinary importance for broadening current scientific knowledge on legume evolution and taxonomy because of its proximity to the hypothetical common ancestor of the tribe Fabeae, as well as for breeding and agronomy of the cultivated Fabeae species due to its perenniality and stress resistance. All this may be feasible only if a concerted and long-term conservation strategy is established and carried out by both academic and geovernmental authorities. The existing populations of V. formosa are in serious danger of extinction. The main threats are domestic and wild animal grazing, foraging, and early frosts in late summer. A long-term strategy to save V. formosa from extinction and to sustain its use in both basic and applied research comprises much improved in situ preservation, greater efforts for an ex situ conservation, and novel approaches of in vitro propagation.

New insight into the history of domesticated apple: secondary contribution of the European wild apple to the genome of cultivated varieties.

The apple is the most common and culturally important fruit crop of temperate areas. The elucidation of its origin and domestication history is therefore of great interest. The wild Central Asian species Malus sieversii has previously been identified as the main contributor to the genome of the cultivated apple (Malus domestica), on the basis of morphological, molecular, and historical evidence. The possible contribution of other wild species present along the Silk Route running from Asia to Western Europe remains a matter of debate, particularly with respect to the contribution of the European wild apple. We used microsatellite markers and an unprecedented large sampling of five Malus species throughout Eurasia (839 accessions from China to Spain) to show that multiple species have contributed to the genetic makeup of domesticated apples. The wild European crabapple M. sylvestris, in particular, was a major secondary contributor. Bidirectional gene flow between the domesticated apple and the European crabapple resulted in the current M. domestica being genetically more closely related to this species than to its Central Asian progenitor, M. sieversii. We found no evidence of a domestication bottleneck or clonal population structure in apples, despite the use of vegetative propagation by grafting. We show that the evolution of domesticated apples occurred over a long time period and involved more than one wild species. Our results support the view that self-incompatibility, a long lifespan, and cultural practices such as selection from open-pollinated seeds have facilitated introgression from wild relatives and the maintenance of genetic variation during domestication. This combination of processes may account for the diversification of several long-lived perennial crops, yielding domestication patterns different from those observed for annual species.