PDF(Pubmed)
Abstract：
OBJECTIVE: Plant breeders are increasingly turning to crop wild relatives (CWRs) to ensure food security in a rapidly changing environment. However, CWR populations are confronted with various human-induced threats, including hybridization with their nearby cultivated crops. This might be a particular problem for wild coffee species, which often occur near coffee cultivation areas. Here, we briefly review the evidence for wild Coffea arabica (cultivated as Arabica coffee) and Coffea canephora (cultivated as Robusta coffee) and then focused on C. canephora in the Yangambi region in the Democratic Republic of the Congo. There, we examined the geographical distribution of cultivated C. canephora and the incidence of hybridization between cultivated and wild individuals within the rainforest.
METHODS: We collected 71 C. canephora individuals from home gardens and 12 C. canephora individuals from the tropical rainforest in the Yangambi region and genotyped them using genotyping-by-sequencing (GBS). We compared the fingerprints with existing GBS data from 388 C. canephora individuals from natural tropical rainforests and the INERA Coffee Collection, a Robusta coffee field gene bank and the most probable source of cultivated genotypes in the area. We then established robust diagnostic fingerprints that genetically differentiate cultivated from wild coffee, identified cultivated-wild hybrids and mapped their geographical position in the rainforest.
RESULTS: We identified cultivated genotypes and cultivated-wild hybrids in zones with clear anthropogenic activity, and where cultivated C. canephora in home gardens may serve as a source for crop-to-wild gene flow. We found relatively few hybrids and backcrosses in the rainforests.
CONCLUSIONS: The cultivation of C. canephora in close proximity to its wild gene pool has led to cultivated genotypes and cultivated-wild hybrids appearing within the natural habitats of C. canephora. Yet, given the high genetic similarity between the cultivated and wild gene pool, together with the relatively low incidence of hybridization, our results indicate that the overall impact in terms of risk of introgression remains limited so far.
METHODS: We collected 71 C. canephora individuals from home gardens and 12 C. canephora individuals from the tropical rainforest in the Yangambi region and genotyped them using genotyping-by-sequencing (GBS). We compared the fingerprints with existing GBS data from 388 C. canephora individuals from natural tropical rainforests and the INERA Coffee Collection, a Robusta coffee field gene bank and the most probable source of cultivated genotypes in the area. We then established robust diagnostic fingerprints that genetically differentiate cultivated from wild coffee, identified cultivated-wild hybrids and mapped their geographical position in the rainforest.
RESULTS: We identified cultivated genotypes and cultivated-wild hybrids in zones with clear anthropogenic activity, and where cultivated C. canephora in home gardens may serve as a source for crop-to-wild gene flow. We found relatively few hybrids and backcrosses in the rainforests.
CONCLUSIONS: The cultivation of C. canephora in close proximity to its wild gene pool has led to cultivated genotypes and cultivated-wild hybrids appearing within the natural habitats of C. canephora. Yet, given the high genetic similarity between the cultivated and wild gene pool, together with the relatively low incidence of hybridization, our results indicate that the overall impact in terms of risk of introgression remains limited so far.
摘要：
目的：植物育种者越来越多地转向作物野生近缘种（CWR），以确保快速变化的环境中的粮食安全。然而,CWR人群面临各种人为威胁，包括与附近种植的作物杂交。对于野生咖啡物种来说，这可能尤其是一个问题，经常发生在咖啡种植区附近。这里,我们简要回顾了野生阿拉伯咖啡（作为阿拉伯咖啡种植）和canephora咖啡（作为罗布斯塔咖啡种植）的证据，然后重点研究了刚果民主共和国扬甘比地区的canephora。在那里,我们研究了雨林中栽培的C.canephora的地理分布以及栽培和野生个体之间杂交的发生率。
方法：我们从Yangambi地区的家庭花园中收集了71个C.canephora个体，从热带雨林中收集了12个C.canephora个体，并对其进行了基因分型测序（GBS）。我们将这些指纹与来自天然热带雨林和INERA咖啡收藏的388个C.canephora个体的现有GBS数据进行了比较，罗布斯塔咖啡田基因库和该地区最有可能的栽培基因型来源。然后我们建立了强大的诊断指纹，从基因上区分野生咖啡，鉴定的栽培野生杂种，并绘制了它们在热带雨林中的地理位置。
结果：我们在具有明显人为活动的区域中鉴定了栽培基因型和栽培野生杂种，以及在家庭花园中种植的C.canephora可以作为作物到野生基因流的来源。我们在热带雨林中发现的杂种和回交相对较少。
结论：在其野生基因库附近种植C.canephora导致了在C.canephora的自然栖息地中出现的栽培基因型和栽培野生杂种。然而，鉴于栽培基因库和野生基因库之间的高度遗传相似性，加上杂交的发生率相对较低，我们的结果表明,到目前为止,在渗入风险方面的总体影响仍然有限.
方法：我们从Yangambi地区的家庭花园中收集了71个C.canephora个体，从热带雨林中收集了12个C.canephora个体，并对其进行了基因分型测序（GBS）。我们将这些指纹与来自天然热带雨林和INERA咖啡收藏的388个C.canephora个体的现有GBS数据进行了比较，罗布斯塔咖啡田基因库和该地区最有可能的栽培基因型来源。然后我们建立了强大的诊断指纹，从基因上区分野生咖啡，鉴定的栽培野生杂种，并绘制了它们在热带雨林中的地理位置。
结果：我们在具有明显人为活动的区域中鉴定了栽培基因型和栽培野生杂种，以及在家庭花园中种植的C.canephora可以作为作物到野生基因流的来源。我们在热带雨林中发现的杂种和回交相对较少。
结论：在其野生基因库附近种植C.canephora导致了在C.canephora的自然栖息地中出现的栽培基因型和栽培野生杂种。然而，鉴于栽培基因库和野生基因库之间的高度遗传相似性，加上杂交的发生率相对较低，我们的结果表明,到目前为止,在渗入风险方面的总体影响仍然有限.
