Diversidade genética e anatomia foliar em acessos de mandioca (Manihot esculenta Crantz)

Abstract

Cassava is found among the main sources of carbohydrates in the world for both food and feed. Consumed both fresh and processed as food or as industrialized products. Various techniques intended to improve the cultivation of cassava have been applied, such as the use of molecular markers and the study of anatomy. This work consists of two experiments. In the first experiment, DNA was amplified 14 microsatellites primers, of which 12 were polymorphic and amplified a total of 26 alleles with two to four alleles per loci. The amplification products were separated by polyacrilamide gel electrophoresis. The genetic similarity was estimated by Dice coefficient and cluster analysis by UPGMA, using the NTSYS program. The diversity parameters were achieved using the POPGENE program. The similarity coefficient ranged from 0.16 to 0.96. The average of observed heterozygosity was 0.18 and 0.46 for expected heterozygosity. One can conclude that the SSR marker was efficient in the study of genetic diversity among the accessions studied. In the second experiment, fully expanded leaves of 13 cassava genotypes were collected and analyzed for quantitative changes under optical microscopy. The genotypes showed great anatomical plasticity for most of the leaf tissue, and the changes occurred in stomatal characteristics, thickness of tissues and in the phloem and xylem. Genotypes UFLA E, IAC 14 and UFLA J are characterized by presenting adaptability to xeric conditions and other genotypes to mesophytes conditions. Thus, the genotypes show desirable characteristics for different environmental conditions.