Caracterização morfoagronômica e molecular de acessos tradicionais de mandioca de mesa oriundos do Paraná e Santa Catarina

Abstract

This study aimed to characterize the sweet cassava traditional accessions and estimate the genetic diversity using morphological and agronomic traits and molecular microsatellite (SSR). The accessions were provided by the Cassava Germplasm Bank of the Universidade Estadual de Maringá, and were collected in peri-urban and rural areas in the states of Paraná and Santa Catarina, totaling 144 accesses. Statistical analysis was performed using multivariate analysis. The matrix of genetic differences were obtained by Average Euclidean Distance in nine quantitative traits and 25 qualitative characteristics (multicategoric) through the similarity index, and through CS Chord Distance used for 25 microsatellite loci. The results indicated that the most divergent combinations of traditional accessions in relation to the qualitative characteristics suitable for further hybridizations in breeding programs occurred in BGM 688 Ld x BGM 353 To, while combinations for quantitative characteristics were BGM 689 Ld x (BGM 526 SM, BGM 499 SM, BGM 39 Ci, BGM 424 SM, BGM 686 Ld, BGM 453 SM, BGM 358 To, BGM 459 SM, BGM 443 SM, BGM 446 SM, BGM 473 SC, BGM 423 SM, BGM 481 SC, BGM 444 SM, BGM 475 To, BGM 32 Ci, BGM 488 SC, BGM 490 SC e BGM 374 To). Regarding molecular markers most loci were considered polymorphic, with an average of 3.36 alleles per locus. Polymorphism Information Content (PIC) values ranged from 0.123 to 0.738 GA SSRY 101 to SSRY to 28. The observed heterozygosis values ranged from 0.000 for SSRY to 0.979 for GA 12, with an average of 0.644. In relation to the genetic diversity the mean value was 0.557 ranging from 0.132 for SSRY 101 to 0,775 for SSRY 28. The most divergent combinations for C. S. Chord Distance indicated for future hybridization in breeding programs were: BGM 444 SM x BGM 15 Mgá, BGM 525 SM x BGM 497 Bts, BGM 444 SM x BGM 684 Ld, BGM 451 SM x BGM 687 Ld, BGM 459 SM x BGM 444 SM, BGM 13 Mgá x BGM 497 Bts, BGM 499 Bts x BGM 689 Ld, BGM 15 Mgá x BGM 436 SM e BGM 689 Ld x BGM 35 Ci, which showed flowering and low incidence of cassava bacterial blight, root rot and super elongation. The Population Structure Analysis revealed the occurrence of 10 groups defined by the probabilistic method. The results showed the existence of large genetic divergence between the sweet cassava accessions in the collection sites.