26 / SEEDWORLD.COM JUNE 2019 IMAGINE YOU’RE WALKING through a grocery store, doing your usual weekly shopping. Everything seems normal, but as you pick up a can, there’s no label. There’s nothing to tell you what the product is, and now you can’t reliably choose anything to eat this week. Now switch gears a little and imagine a germplasm bank. Without the right labeling on different varieties, it’s difficult to tell what’s new and what has already been discovered when working on new research projects. That’s where the Molecular Maize Atlas steps into play. About nine years ago, the International Maize and Wheat Development Center (CIMMYT) started an initiative called the Seeds of Discovery (SeeD). This initiative uses a multipronged strategy to seek solu- tions to facilitate easier access to and use of maize and wheat genetic resources. “One of the aims of SeeD was to best characterize germplasm,” says Sarah Hearne, molecular geneticist and maize lead of SeeD. “At CIMMYT, our international germplasm bank holds in trust one of the largest and most diverse publicly available maize collections in the world.” To combat the lack of labeling stand- ards, SeeD decided to work on a labeling process for the germplasm bank: the Molecular Maize Atlas. The Molecular Maize Atlas is a knowl- edge and information platform that brings genotypic data resources and associated tools together. This genotypic data provides unifying information across landraces and acts as a common back- bone, which other valuable information such as phenotypic data, can be added. “Nine years ago, genotyping and sequencing was getting cheaper, so we could start to characterize everything in the bank using high density genotyping,” Hearne says. “When you think of your school atlases, you had different kinds of infor- mation all layered together on top of a common framework. The Molecular Maize Atlas conceptually does the same thing. It shows what the genotype of a particular maize accession is, where germplasm is from, when it was collected, what envi- ronment it was collected from, any phe- notypic characteristics which have been measured on that accession and other information that when combined gives us very important insight,” Hearne says. For CIMMYT, starting this program accomplished one major goal: it lowered the transaction cost for accessing germ- plasm bank materials for breeders. “Not all genetic diversity is beneficial for breeding and landraces carry a lot of crud with to beneficial variation,” Hearne says. “A lot of breeders are resistant to go With so much germplasm to categorize, what’s the best way to label them? Seeds of Discovery is working on the answer. Alex Martin amartin@issuesink.com THE MOLECULAR MAIZE ATLAS ENCOURAGES GENETIC DIVERSITY to germplasm banks because you never know what you will get, so we use the atlas to make informed selections and lower these transaction costs.” SeeD has also implemented a pre- breeding program to help cross exotic germplasms into more breeder-friendly breeding lines. Hearne says before pre- breeding, exotic varieties looked like a tiger, and they didn’t always behave well. With pre-breeding, the tiger turns into more of a street cat; it resembles some- thing closer to what you would use in an inbred program and is useful as donor materials if you want to develop new inbred lines for hybrids, develop open pollinated varieties for more marginal farming systems or to use in participa- tory plant breeding in landrace-based systems. The Molecular Maize Atlas helps bring landraces into active use via the efforts of germplasm bank users. Currently, examples include the use of landraces in heat tolerant research, development of new drought tolerant breeding lines and participatory maize breeding with smallholder farmers to improve landrace disease tolerance. “We’re encouraging more and more use as we go along,” Hearne says. “We want to see more targeted use of the materials available in the germplasm bank.” Ultimately, SeeD wants to see the benefits of the Molecular Maize Atlas help the entire maize community, including those who have been the custodians of these valuable resources — small holder farmers. SW Sarah Hearne serves as molecular geneticist and maize lead of SeeD. PHOTO: CIMMYT