DNA Fingerprinting for Cultivar Identification
Most cranberry fruits look very similar. Over time, cultivated bogs have become contaminated with non-cultivar types. Contamination can come from many sources including encroachment of cultivated bogs by wild-types and establishment of seedlings from dropped fruit. These situations have created problems in the industry when attempting to characterize a particular cultivar for cultural attributes.
There are two basic methods to improve crops. The traditional method is through selective breeding. The most successful and widely cultivated cranberries and other crops are the direct result of years of careful breeding. Breeding however has its drawbacks. Breeding is very time consuming and can take many years before a new cultivar can be developed. Part of the reason breeding can take so long is because undesirable genes are often transferred to progeny along with the desirable genes. The undesirable genes have to then be removed through subsequent crosses. Another limitation of breeding is that the genes available for crop improvement are limited to plants that can be sexually crossed with the crop of interest.
The advent of molecular biology has given rise to a new approach to crop improvement. Genes for specific characteristics, such as disease resistance, can now be directly inserted into elite cultivars. This technology requires many steps that vary from crop to crop. We are now developing the methods to insert genes into cranberry, a process referred to as 'transformation'.