Location: Corn Host Plant Resistance ResearchTitle: Toward Cost-Effective Fingerprinting Methodology to Distinguish Maize Open-Pollinated Varieties) Author
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2009
Publication Date: 3/1/2010
Citation: Warburton, M.L., Setimela, P., Franco, J., Cordova, H., Pixley, K., Banziger, M., Dreisigacker, S., Bedoya, C., Macrobert, J. 2010. Toward a Cost-Effective Fingerprinting Methodology to Distinguish Maize Open-Pollinated Varieties. Crop Science. 50:467-477. Interpretive Summary: Determining the identity of open pollinated varieties (OPV) of crop plants is a complicated procedure. Unlike self pollinated, hybrid, or cloned varieties, each individual in the OPV is genetically different from all others. However, it is possible to genetically fingerprint at the population level using molecular genetic markers and a sufficiently large number of individuals drawn at random from the population (generally, 15 or more). Fingerprinting a maize population will make it possible to police the claims of seed providers about the identity of the seeds they provide to farmers. In Africa, if seeds are sown that are unadapted to the growing environment, the season’s crop and the farmer’s livelihood can be ruined. The identity and purity of the seeds being provided to farmers on the market or in disaster relief efforts are sometimes suspect, as unscrupulous or untrained dealers may mix or substitute, for example, cheaper grain from food aid shipments for certified OPV seed. Molecular genetic markers can be used in a labor and cost saving bulking technique to unambiguously identify maize OPVs, protect breeder’s rights, and farmer’s livelihoods.
Technical Abstract: In Africa, many smallholder farmers grow open pollinated maize varieties (OPVs), as they allow seed recycling and out-yield traditional farmer’s (unimproved) landraces. One popular OPV, ZM521 released by the International Maize and Wheat Improvement Center (CIMMYT), has been provided to farmers, often by Non-Governmental Organizations (NGOs) who help farmers gain access to improved seeds, particularly following disasters in which original seed is lost. However, NGOs often rely on local seed suppliers to provide the seed, and in some years the seeds provided to the farmers are suspected not to be of the promised variety. Here we present methodology to prove within a high level of confidence if two samples of seeds are the same genetic population or not, despite the difficulties involved in fingerprinting heterologous populations. In addition to the actual heterogeneity within populations, these difficulties include sampling errors, differences due to seed sources (the fields or years in which the seeds were multiplied), and possible mixing of seed or flow of pollen from neighboring fields. Despite these confounding sources of variation, we show the possibility to conclusively identify each population. This methodology will allow breeders, seed companies, government agencies and NGOs to ensure that the correct seed of high yielding, locally adapted OPVs reach farmers and generate the highest yields possible in their fields.