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DNA fingerprinting – sifting the fake from the genuine

An improved tool can play a key role in distinguishing open-pollinated maize varieties (OPVs) and ensuring that seed being sold is genuine. DNA fingerprinting, also referred to as DNA profiling, enables one maize variety to be distinguished from another using molecular markers. It is an important way to help ensure that only certified seed enters the market, and to identify individuals or companies that sell fake seed.

A team of CIMMYT scientists has tested a new technique to differentiate OPVs using a more costefficient method of DNA fingerprinting. Their work was published in Crop Science 50: 1-11, and is accessible at the Drought Tolerant Maize for Africa (DTMA) project website.

In January 2010, 61 samples of the OPV ZM 521 taken from various seed lots in Malawi, Zambia, and Zimbabwe underwent the new cost-efficient DNA fingerprinting at Proteios, a laboratory in South Africa. Peter Setimela, maize breeder, and John MacRobert, seed systems specialist, presented the results of these tests to the Zimbabwe Emergency Agricultural Input Project (ZEAIP), the World Bank, and SeedCo Ltd., a seed company in Zimbabwe. ZEIAIP wants to ensure that the seed purchased for relief is genetically pure and genuine, which is also of interested to the World Bank, as it supports seed relief efforts in the country and tries to reduce the dissemination of fake seed.

Using this methodology, the scientists were able to conclusively identify the OPVs, thus ensuring that the correct high-yielding seed of locally-adapted varieties could reach the farmers. Results from the fingerprinting also determined, however, that one hybrid had been mislabeled as ZM521. If this seed had been planted, it would have yielded much lower than expected, and is just one example of the importance of seed purity testing.

In Africa, many farmers grow OPVs rather than hybrid varieties because the seed can be saved and replanted without the yield loss associated with the replanting of hybrid maize seed. Compared to hybrids, OPVs are less uniform and it is easier for seed companies to sell fake or non-certified seed.