Hybridisation is the interbreeding of genetically distinct groups that can lead to introgression – an exchange of genetic material between species. Hybridisation is of conservation concern when an alien invasive species is involved, as it can lead to a loss of local genetic adaptations and genetic diversity. Hybridisation is a significant threat for many dabbling ducks where interbreeding with the closely related invasive Mallard Anas platyrhynchos is extremely common. Phenotypic evidence suggests that Mallard populations in South Africa hybridise with the indigenous Yellow-billed Duck Anas undulata. The aim of this study was to determine the incidence of hybridisation between Yellow-billed Ducks, occurring in central and northwestern South Africa, and introduced Mallards. Genetic variation between Mallards, Yellow-billed Ducks, and their inferred hybrids was assessed using mitochondrial and microsatellite DNA markers. All samples inferred to be hybrids based on the phenotype were found to have Yellowbilled Duck mitochondrial DNA and showed minimal evidence of admixture across the microsatellite markers. Thus, these results do not support the notion that hybridisation between Mallards and Yellow-billed Ducks is prevalent in central and northwestern South Africa. However, hybridisation could be occurring where Mallards are found in higher abundance, such as in the Western Cape Province. Therefore, continued monitoring of this potential hybridisation should be performed frequently and throughout South Africa.

杂交是遗传上不同群体的杂交，这可能导致基因渗入-物种之间遗传物质的交换。当涉及外来入侵物种时，杂交是需要保护的问题，因为杂交会导致当地遗传适应和遗传多样性的丧失。对于许多涉水鸭而言，杂交是一个重大威胁，在这种情况下，与密切相关的入侵野鸭Anas platyrhynchos杂交非常普遍。表型证据表明，南非的绿头野鸭种群与土著黄嘴鸭Anas undulata杂交。这项研究的目的是确定发生在南非中部和西北部的黄嘴鸭之间的杂交发生率，并引入绿头鸭。使用线粒体和微卫星DNA标记评估了野鸭，黄嘴鸭及其推断的杂种之间的遗传变异。发现所有根据表型推断为杂种的样品均具有黄嘴鸭线粒体DNA，并且在微卫星标记上几乎没有混合迹象。因此，这些结果不支持在南非中部和西北部普遍存在野鸭和黄嘴鸭之间的杂交的观点。但是，在野鸭数量较多的地方，例如西开普省，可能发生杂交。因此，