Scientists from the UN in Palmira and CIAT found in cassava genotypes collected in the departments of the Atlántico, Magdalena, Córdoba and Sucre, high genetic variability that could prevent their extinction.
Cassava (Manihot esculenta Crantz) is considered the fourth most important staple food in the world, after rice, wheat and maize. Its role is essential in the diet of millions of people worldwide, since it is an important source of energy in food.
In Colombia, the main growing area is the Caribbean region. There 42% of national production is concentrated. And, as in other countries, it is mostly managed by small cassava producers. However, according to based researchers, these crops made up unidentified local genotypes are improved varieties or are unaware of the extent of its variability.
Professor Franco Alirio Vallejo, one of the directors of the project, explains: "the knowledge of genetic variability of the species facilitates decision-making in breeding and conservation programs. And the germplasm prevents the loss of wild and cultivated varieties, since it expects or reduces genetic erosion."
Therefore, in order to examine them, researchers from the International Center for Tropical Agriculture (CIAT) and the UN in Palmira used microsatellite molecular markers (simple sequence repeat, SSR).
"These markers have been widely used for these studies. 36 have been identified as the most polymorphism and have been used in research with genotypes from other countries," reports, in its bibliography, Adriana Mercedes Alzate, project engineer and researcher.
Scientists say that in some of the previous work done, Colombian varieties have been included from the CIAT`s seed bank.
"However, in the country there have been no studies of genetic variability that include cassava accessions collected directly from the farmers' fields," said Alzate.
The germplasm was collected on small farms that had an area of between 0.5 and 12 hectares and located in the departments of Córdoba, Sucre, Atlantico and Magdalena.
"It was a type of clustered multistage sampling and the existing group of growers in each municipality was considered as a conglomerate. First, the township was randomly selected within each department. Then the properties of each
municipality," points out Professor Vallejo.
They evaluated 717 cassava genotypes collected. Thus, using multiple correspondence analysis (MCA), they established six Genetic differences that account for 81% of the variation.
The coefficient of genetic differentiation between groups (GST) was low (0.18), which indicates, according to Alzate, "that variability is not due to differences between the groups, but differences within each group, hence within these is high."
Professor Vallejo concludes: "The genetic variation measures in this research showed that, in these cassava crops, there is high heterozygosity (HI: 0.56087). This confirms the crosslinking of cassava and its highly heterozygous nature. Its allogamous (cross-pollination) condition favors the segregation and the generation of new genetic variability."
Source: UNA