Name: RAFAELA BARRETO CAZAROTO GROBÉRIO
Publication date: 27/02/2025
Examining board:
Name |
Role |
|---|---|
| ANDREIA BARCELOS PASSOS LIMA GONTIJO | Examinador Interno |
| EDILSON ROMAIS SCHMILDT | Presidente |
| OMAR SCHMILDT | Examinador Externo |
Summary: Papaya (Carica papaya L.) is a tropical plant of great economic importance, notable for its rapid growth and early production, and is one of the most important and widely cultivated crops in tropical and subtropical regions. However, one of the main challenges of this crop is the limitation of commercially available varieties that meet the demands of domestic and foreign markets. A viable alternative to overcome this limitation is to expand the genetic base of papaya through breeding programs that use hybridization. In this context, three studies were conducted. The first chapter presents a literature review, based on the Scopus database, on the evolution of research on molecular markers in the genetic improvement of papaya from 2013 to 2023. The analysis revealed 30 articles on the use of molecular markers in papaya cultivation during the period evaluated, with the largest number of publications in the years 2014, 2015 and 2019. The second chapter addresses the reduced size of the genotype ‘Baixinho de Santa Amália’ and the shorter petiole length of the ‘Golden Pecíolo Curto’, in addition to the evaluation of new hybrids involving these materials. The experiment was conducted at Fazenda Santa Terezinha, in Linhares-ES, with eight genotypes: four of reduced size, two of normal size and two hybrids. A completely randomized design was used, in split plots, with treatments of application or not of GA (100 ppm) in seedlings at 7 and 14 days after emergence, with evaluations performed at 21 days. Analysis of variance indicated a significant interaction between genotypes and GA application. Normal-sized and hybrid plants presented etiolation, while reduced-sized genotypes maintained limited growth, even after application. These results suggest that the observed characteristics do not result from a deficiency in gibberellic acid production, but possibly from changes in the regulatory domain of the seedling response to gibberellin. The third chapter aimed to evaluate the agronomic characteristics of new papaya genotypes in order to perform a selection for the papaya production system. The experiment was carried out in the municipality of Linhares, Espírito Santo, with a randomized block experimental design. Eight months after planting, fifteen agronomic traits were analyzed in twelve genotypes, six hybrids (BSAG x THB, JS12 x BSAG, BOG x THB, UC01 x BOG, JS12 x BOG and 72/12 x BOG1-3), four lines (BOG1-3, BOG1-12, BOV and BSAG) and two controls (THB and 72/12). Statistical analyses were performed using analysis of variance, Scott-Knott clustering test, genetic diversity analysis and principal component analysis, all using R software. Univariate analyses demonstrated significant differences between genotypes for all agronomic traits. Multivariate analyses were able to form three distinct groups, the first composed of genotypes with reduced size and smaller fruit size, the second group with hybrids with higher fruit weight and the third group with plants with intermediate fruit weight. The papaya varieties BOG1-3, BOG1-12 and BOV were selected for the Solo group and the hybrids JS12 x BOG1-3 and JS12 x BSAG for the Formosa group, these genotypes being interesting alternatives to be explored in new evaluations for later possibility of indication for papaya producers.
