Diversidade genética e química em germoplasma de gengibre (Zingiber officinale)

Abstract

Chemical and genetic diversity of ginger germplasm (Zingiber officinale) Plant genetic resources exhibit a true and potential value for agriculture due to their importance in breeding and conservation programs. This study aimed to characterize the genetic and chemistry diversity of ginger germplasm of Genetics Department of the ESALQ/USP, through 18 phenotypic descriptors, 13 AFLP markers combinations and chemical composition analysis of essential oil. The germplasm was combined by accessions coming from diferent Brazilian states, along with some accessions introduced from Colombia. During the collection, 34 farmers were interviewed in three states: São Paulo (SP), Espírito Santo (ES) and Paraná (PR). Ginger is mainly cultivated by small farmers whose main income source is agriculture. In the chemical composition analysis, a total of 61 compounds were identified. The accessions presented chemical variability according to the analysis of variance. The essential oil was rich in monoterpenes (82.35%), being the geranial (20.41%) and the neral (13.36%), both referred to as citral, the most abundant compounds. The α-zingiberene, 1,8-cineole, linalool and β-phellandrene compounds were relevant in the chemical diversity analysis of the accessions, while the dendrogram based on the complete linkage method (LC-VD) classified the germplasm into two groups: landraces and cultivars accessions. In the agromorphologic characterization, qualitative traits showed little variation, while moderate to low variability was observed for quantitative traits, although some divergent accessions were identified. The principal component analysis explained 82% of the total variation in the first three components, wherein the accessions distribution on the scatter plot was consistent with the groups formed by the Tocher method, with the Gen-18, Gen-24, Gen-65 and Gen-42 accessions as the most divergent ones from the phenotypically germplasm. In the molecular characterization, 13 AFLP markers combinations generated an average of 113.5 polymorphic loci, with a ratio of 96.85% of polymorphism in the overall collection. Estimates of Nei genetic diversity (H j), Shannon index (I) and alleles effective number (n e) were higher in Colombian accessions (0.501; 0.396 and 1.508, respectively). The AMOVA showed that most of the variation (63%) occurs between the two countries and the F ST =0.153 index suportted this result, indicating high genetic differentiation between Brazilian and Colombian accessions. The groupings provided by Structure and the dendrogram based on Jaccard coefficient complement were consistent with each other and showed that Brazilian accessions are genetically similar. In general, there is no influence of the accesses geographic origin in the chemical, phenotypic and molecular grouping pattern. The introduction of new genetic materials in Brazil, will certainly contribute to a broader genetic basis of this species.

Caracterização fenotípica e molecular de Zingiber officinale roscoe cultivado no norte de Mato Grosso, Brasil

“…Os estudos de caracterização, os bancos de germoplasma e, consequentemente, os programas de melhoramento genético da espécie estão concentrados na Ásia, região de maior produção mundial, sendo escassos os trabalhos que avaliam o germoplasma brasileiro (AKSHITHA et al, 2019;BABU et al, 2017;BASAK et al, 2019;BLANCO et al, 2015;BLANCO et al, 2017;DAS et al, 2020).…”

“…padrão de união semiséssil. Com exceção da forma da lígula (FL), a homogeneidade dos demais descritores (ML, PF, DF, OF e PUF) também foi observada porBlanco (2015), ao avaliar acessos de Z. officinale oriundos da Colômbia e de diferentes estados do Brasil e mantidos no Banco de Germoplasma da ESALQ/USP, sendo que está similaridade demonstrou a baixa variabilidade genética da espécie, o que pode ser atribuído à reprodução por propagação vegetativa.…”