Microsatellite Polymorphisms in Cassava Landraces from the Cerrado Biome, Mato Grosso do Sul, Brazil

Abstract

Using nine microsatellite loci, we investigated genetic structure and diversity in 83 Brazilian cassava accessions, including several landraces, in the Cerrado biome in Mato Grosso do Sul, Brazil. All nine loci were polymorphic, averaging 6.00 alleles per locus. Treating each of seven municipalities as a cassava group or population, they averaged 3.5 alleles per locus, with 97% polymorphic loci, high values for observed heterozygosity (0.32) and gene diversity (0.56). Total genetic variability was high (0.668), and most of this genetic variability was concentrated within municipalities (0.577). Cluster and structure analyses divided accessions into two major clusters or populations (K = 2). Also, a significant genetic versus geographic correlation was found (r = 0.4567; P < 0.0260). Migratory routes in the Cerrado are considered main contributors to the region's high cassava diversity and spatial genetic structure, amplifying interactions between traditional farmers and the evolutionary dynamics of this crop.

Genetic divergence among accessions of cassava (Manihot esculenta Crantz) sampled in the Tapajós region, State of Pará, using agronomic characters and microsatellite markers

“…Among the phenotypic descriptors, the ones with agronomic importance are most influenced by the environment; however, they help to identify adapted accessions with productive potential (VIEIRA et al, 2013). Molecular markers are also frequently used in the estimation of genetic divergence in cassava (ASARE et al, 2011;FERREIRA et al, 2008;SIQUEIRA et al, 2010), since they are not affected by the environment and are efficient in the detection of a large number of differences among accessions (KRISHNAMURTHY et al, 2013). However, they have the disadvantage of accessing all the genome and not only the regions expressing traits of agronomic importance (VIEIRA et al, 2011).…”

“…Microsatellites, or SSR (simple sequence repeats) molecular markers, are co-dominant and highly polymorphic markers (SIQUEIRA et al, 2010) with a high abundance in plants (MBA et al, 2001); they are used in studies of genetic divergence.…”

Physicochemical properties of three sugary cassava landraces

“…The Manihot genus (ALBUQUERQUE, 1969;HILLOCKS et al, 2002) may have originated and diversifi ed in Brazil where there is great genetic variety, mainly of local diversity, that is restricted to a few agriculturists. These varieties are known as landraces (SIQUEIRA et al, 2010).…”

Distribution, management and diversity of yam local varieties in Brazil: a study on Dioscorea alataL.

“…This study also showed that there is a clear regionalization in the assignment of popular names for D. alata local varieties, according to their morphology, uses or origin. The role of farmers in maintaining the local agro-biodiversity, whether in home gardens or fields, is important for the maintenance of the genetic diversity of yams and other crops over generations (Chair et al, 2010;Siqueira et al, 2010;Bressan et al, 2011;Veasey et al, 2012). However, for these varieties to be maintained at an on farm conservation basis, agroecological conservation policy goals must be considered, as well as more studies emphasising the importance of yams in rural areas.…”