Bioscience in brief
Plant genetics and crop breeding
Where do our crops come from? III. Banana
Bananas are hugely important as food and cash crop for smallholder farmers in Africa: 70 million people in 15 countries in Sub-Saharan Africa depend on bananas and plantains for their livelihood and nutrition.
Wild relatives of cultivated bananas have numerous hard seeds. In these cases seedlessness is a very desirable characteristic. Cultivated bananas are triploid – they have three sets of chromosomes instead of two – and hence they fail to develop seeds, which makes them a very good source of food for humans. Because they are sterile, banana plants need to be propagated by cuttings. This characteristic also has drawbacks: any diseases afflicting the mother plant will also be present in all the plants derived from it. In addition, it is very difficult to improve varieties, for example to introduce resistance to a viral disease, by conventional breeding techniques since it is very problematic, though not totally impossible, to cross-breed them to another type of banana.