Banca de DEFESA: Livia de Moura Pio

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : Livia de Moura Pio
DATA : 10/07/2025
HORA: 08:00
LOCAL: Unemat - Tangará da Serra
TÍTULO:

STUDY OF INHERITANCE OF FUSARIUS WOUND RESISTANCE AND GENETIC VARIABILITY IN PINEAPPLE ACCESSES VIA MOLECULAR MARKERS

PALAVRAS-CHAVES:

Genetic resistance; DNA markers; genetic improvement; Ananas comosus

PÁGINAS: 30
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Melhoramento Vegetal
RESUMO:

Pineapple (Ananas comosus) is one of the most commercially valued tropical fruits, with Brazil consolidating itself as one of the world's leading producers. Despite its economic importance, these crops face serious phytosanitary challenges, with fusariosis being one of the most devastating diseases, responsible for significant production losses. In addition, studies with molecular markers related to genetic variability studies are still rarely found in the literature on pineapple. Thus, a study on the genetic inheritance of important traits in pineapple cultivation, as well as the genetic-molecular characterization of pineapple accessions, can significantly contribute to a better choice of the most appropriate breeding method for the introgression of alleles carrying traits of interest. Thus, this study aims to analyze the genetic inheritance of resistance to fusariosis in populations obtained from crosses between pineapple cultivars, as well as to evaluate the variability and genetic structure of 18 accessions of the UNEMAT Pineapple Genetic Improvement Program by means of molecular markers. For the first experiment, crosses were performed between resistant (BRS Imperial and BRS Ajubá) and susceptible (Jupi and Gigante de Tarauacá) cultivars. The resulting populations were phenotyped and analyzed for two traits related to genetic resistance to fusariosis, severity and AACPS, using genetic parameters estimated via REML/BLUP. Subsequently, the chi-square test will be applied based on the hypothesis of monogenic inheritance (3:1) to evaluate the segregation of the trait of resistance to fusariosis in the different populations. For the second experiment, the molecular genetic characterization of the 18 pineapple accessions was evaluated using 50 microsatellite markers (SSR). Diversity parameters of the accessions were estimated for each marker considering the entire population, with the aid of the GenAIEx 6.5 program, based on the following parameters: (Na, Ho, He, I, F). Diversity indices were also estimated for each accession individually, considering all loci analyzed. Having (H, F, PIC) as main parameters. The analysis was performed using PowerMarker software. Genetic dissimilarity estimates were converted into numerical code for each allele per locus, forming a matrix used to calculate genetic distances with three different indexes: unweighted index, weighted index and the Smouse and Peakall index, using GENES software. After obtaining the distance matrix, the accessions were grouped based on the dissimilarity matrix, where a dendrogram was constructed by UPGMA cluster analysis, with the aid of R statistical software. The consistency of the clusters was verified based on bootstrap resampling performed by the Pvclust package of R software, using 1000 permutations. The degree of relatedness between the genotypes was estimated based on the Loiselle coefficient via SPAGeDi software. The genetic structure of the population was evaluated by Bayesian analysis in the STRUCTURE software, with 10 simulations being performed for K ranging from 1 to 5, with 25,000 and 75,000 interactions, respectively. The results revealed moderate genetic variability, with clusters that reflect the origin and parentage of the materials. The UPGMA cluster analysis divided the accessions into three distinct groups. The population structure, analyzed by the Bayesian method, indicated the formation of two genetic groups, corroborating the need to introduce new materials to expand the genetic base of the breeding program. The results of this study provide valuable information for the selection of parents in future crosses, aiming at obtaining cultivars with resistance to fusarium wilt, thornless leaves and other desirable agronomic characteristics. The combination of inheritance and genetic diversity analyses proves to be an effective approach to optimize breeding strategies, contributing to the sustainability and development of new pineapple cultivars in Brazil.

MEMBROS DA BANCA:
Presidente - 131991001 - WILLIAN KRAUSE
Interna - 305853001 - EILEEN AZEVEDO SANTOS
Externa à Instituição - DAYANE CASTRO SILVA - UFMT
Externo à Instituição - MARCELO VIVAS - UENF