Germplasm Diversity and Plant Breeding Programs

Selecting the germplasm to use is the most important step as it will affect every result of your work from this point forward. Available germplasm resources can include cultivated varieties and landraces (traditional varieties), wild species or relatives, commercial cultivars and other breeding lines (Figure 10).

Figure 10:  A field illustration of a gene bank:  the potato collection at the IPK genebank, Germany Image from the IPK genebank,

Improved cultivars (and even landraces) are often associated with low genetic diversity, especially in the self-pollinated species.

However, increasing diversity by introgression from wild relatives can be complicated by the existence of crossing barriers or poor hybrid fertility. Sometimes, these can be overcome by the use of techniques such as embryo rescue, etc.   Figure 11 shows the embryo rescue of grape seeds.

Figure 11: Embryo rescue is essential to overcome hybrid infertility. Photo from USDA-ARS image gallery