As severe weather and evolving crop diseases threaten farmers’ livelihoods and global food security, scientists are using novel DNA tools and informatics to unearth high-value traits from vast maize and wheat seed collections, for use in breeding climate-resilient varieties to feed the future.
Thousands of years ago, the domestication of maize and wheat from wild grasses sustained the rise of great civilizations. Migration, trade and conquest eventually spread those grains to every corner of the world. Some varieties became tolerant to dry conditions, others to heat, frost, local diseases, and long or short growing seasons, over centuries of selection and breeding by farmers.
Realizing that modern varieties would supplant these locally-adapted “landraces,” breeders and other specialists began to gather and conserve them in organized, cataloged collections in refrigerated genebanks.
“The genetic variation stored in the CIMMYT genebank, comprising 150,000 wheat collections and 28,000 maize collections, is crucial to developing the stress resistant maize and wheat varieties of the future,” says Kevin Pixley, Director of CIMMYT’s Genetic Resources Program, “but plant breeders are often reluctant to use that diversity.”
The reason, explains Pixley, is that the unique and valuable traits from landraces come with many genes for less desirable, wild characteristics, which have to be removed through repeated crosses and selection. This multiplies the time and cost of creating elite varieties.
“It’s like extracting and purifying gold from deep mines, so engineers and artisans can craft it into specialized products for industrial or personal use,” Pixley explains, adding that DNA markers and other advanced technologies are now bringing the “gold” of seed collections within reach of crop breeders.
“To help breeders, CIMMYT is crossing landraces with elite varieties to develop ‘bridging germplasm’ halfway in performance between unimproved and elite lines, but with increased stress adaptation or quality traits from the landraces.”