Study on the genetics of traditional maize in Chile opens up possibilities for crop diversification and resilience to climate change

Through the molecular analysis of choclero corn, a study led by the Agricultural Research Institute (INIA) revealed unprecedented information on the genetic diversity of traditional corn varieties and their role in improving national agricultural crops.

Celeste Skewes, Science in Chile.- Given the current climate crisis, having a variety of foods that can adapt to extreme weather conditions becomes essential for the country’s food security. In this context, the researcher from the La Platina Agricultural Research Institute sought to study the molecular diversity of a staple food of Chilean culture: choclero corn.

Choclero corn is a variety of pre-Columbian corn that is consumed immature and is classified as a vegetable. It has an important cultural and economic value for the country, as it is an essential ingredient in various preparations that characterize Chilean cuisine. Of the 23 races of maize described for Chile, choclero is the only variety cultivated commercially on a large scale, reaching 13.6% of the total national area destined for horticultural production.

Food reserve for future generations

Currently, the Network of Germplasm Banks of INIA has a collection of more than 1,300 accessions – these are representative samples – of traditional varieties of maize collected from different agricultural and peasant areas of the country since the 1950s. Despite being the largest reserve of these seeds in Chile, this abundant heritage of genetic material continues to be underutilized.

“The genetic variation of the species is of fundamental importance as it is a prerequisite for crop improvement strategies, in addition to being the basis for the genetic fingerprint, necessary to differentiate and classify the different types of maize. Local varieties or farmers’ varieties are populations with high genetic variability and adaptability to the agroecological systems where they originated, so many studies highlight the potential of local varieties as a source of new alleles to increase the diversity of gene pools,” he explains. Erika Salazar, PhD in Agricultural Sciences, researcher at INIA La Platina and specialist in the conservation of genetic resources.

The research led by Dr. Salazar aimed to estimate the genetic diversity and population structure of both local maize varieties and pure lines developed by the INIA Maize Improvement Program (currently discontinued), to determine if there are sources significant diversity of alleles in both groups feasible to be used by the current improvement programs for corn choclero existing in Chile.

under the microscope

To study the genetic diversity of choclero maize, the researcher used 10 microsatellite-type molecular markers -tools used to analyze the diversity of the genome in a species- in 34 accessions of traditional varieties of chocleras conserved in the Germplasm Bank of INIA, in addition to 22 pure lines.

“Through this analysis we were able to quantify genetic diversity and understand how it is organized. This allowed us to observe existing structures, that is, on the one hand, groups of very similar varieties grouped together and that distance themselves from other groups of accessions that make up another group. It is precisely these differences between groups -the structure- that are important for a genetic improvement program, since in order to have new variants, genetic distance is needed to develop new combinations and thus have individuals with new characteristics”, explained Dr. Salazar.

A look towards the future

This analysis revealed a great variation between the accessions, both within and between the traditional varieties and the pure lines created. Two different groups of germplasm were found -in addition to subgroups-, in which important differences could be identified in the number of alleles, genetic diversity by locusunique alleles for locus and population structure.

The molecular variability discovered in this study presents key genetic information for corn corn crop improvement programs in the country and sets a precedent for future studies in the area. But, in addition, molecular genetics contributed to determining that not everything classified as a traditional variety in choclero was. In fact, some samples collected in the 1980s corresponded to advanced lines developed by the breeding program maintained by INIA in 1970, which were released into farmers’ fields due to the demand for better quality seed. These antecedents are of great relevance for the conservation and precise documentation of the conserved germplasm. On this, Dr. Salazar concludes: “Future studies based on population genetics, including other collections of genetic resources of other varieties of Chilean maize, will help to understand and explore this gene pool more effectively in breeding programs for maize.” corn”.

https://www.sciencedirect.com/science/article/pii/S0304423817304843