Format: ORAL

Tram Vi1,2, Julie Orjuela1, Philippe Cubry1, Ngan Giang Khong2, Viet Ha Phan4, Pierre Marraccini1,3, Yves Vigouroux1, Valerie Poncet1

1 UMR DIADE, Univ Montpellier, IRD, CIRAD, Montpellier, France. 2 National Key Laboratory of Plant Cellular Biotechnology, Agricultural Genetics Institute, Hanoi, Vietnam. 3 UMR DIADE, CIRAD, Montpellier, France. 4 Western Highlands Agriculture & Forestry Science Institute, Buon Ma Thuot, Vietnam.

Crops are generally cultivated outside of their native range. Optimal climatic suitability for crop production is raising more concerns, especially in the context of climate change. Robusta coffee (Coffea canephora) is indigenous to west and central Africa, but is also widely grown on other continents. Vietnam has been the worlds largest Robusta producer since the 2000s, but is currently facing the risk of yield loss due to climate change. Assessing the suitability of wild genetic material to local climate conditions in Vietnam is essential for sustainable improvement of Vietnamese Robusta coffee. We first compared climatic conditions between native environments in Africa and that in Vietnam, using bioclimatic variables. The wild populations were highly differentiated into five main genetic groups, but only one of these (group ER from DRC) was mainly found in cultivated elite varieties in Vietnam, with a minor proportion of group AG from Gabon and Angola. A negative relationship between climate distance to the native range of group ER and coffee yields at the planted areas was found, and used to predict future coffee yields. The climate distance suggested higher suitability of the minor group (AG) in Vietnam. Using a reference-free approach, more than 18M of k-mers (substrings of sequence reads at 31-bp length) were detected in association with bioclimatic variables. Functional annotation of these candidate k-mers identified putative proteins related to gene regulation. They were used to predict the genetic changes that the wild individuals would require to fit the local environment (genetic offset) in the present and future Genetic offsets revealed variation between the different groups, and also suggested that the most suited genotypes came from the group AG. The results would be useful for planning strategies to improve adaptability of Vietnamese Robusta coffee.