Fernando Antonio Souza de Aragão

This study investigated the differences between ripening patterns of two homozygous lineages of melons, yellow A5, a non-climacteric inodorus, and Charentais C1, a climacteric cantalupensis, regarding the physiological processes related to postharvest quality with a focus on carbohydrate metabolism and osmotic potential. Melons underwent significant changes as maturation progressed from 24 to 34 days after pollination (DAP) for the non-climacteric A5 lineage and from 18 to 28 DAP for the C1 climacteric lineage. The most discriminant variables for the non-climacteric pattern of A5 melons were the higher activity of cell wall hydrolase PME and lower firmness, the higher activity of enzymes involved in carbohydrate metabolism, and sucrose accumulation. In contrast, climacteric C1 melons reach physiological maturity at 24 DAP, do not accumulate sucrose, and enzyme β-GAL plays a key role in cell wall breakdown, contributing to softening and to soluble solids content. A5 melons exhibited greater TSS and soluble solids content, and even though the osmotic potential did not change significantly, the VIP results highlighted it as an important variable for discriminating between its maturation stages. Meanwhile, in the C1 melon, the increase in soluble solids content influences the more negative values of osmotic potential, not by changes in TSS content, and thus may be associated with fruit growth.

The objective of this work was to characterize the physicochemical variability of cashew (Anacardium occidentale) nut kernels across 50 accessions of the Brazilian cashew germplasm bank, evaluate the potential of portable near-infrared (NIR) spectroscopy to predict quality parameters and identify accessions with superior lipid content. Proximate analyses of moisture, ash, protein, and lipid contents, in addition to fatty acid profiling, revealed a wide genetic variability among the accessions. Lipid content ranged from 38.17 to 47.90%, and protein content from 13.66 to 22.41%, indicating a significant negative correlation between these constituents. Accessions with a high lipid content presented a high proportion of unsaturated fatty acids (~78%), especially oleic acid (52-56%), evidencing their potential for nutritional and industrial applications. The multivariate regression models based on interval partial least squares applied to NIR spectra of whole kernels showed a satisfactory performance in predicting lipid content. Therefore, portable spectroscopy has potential for rapid phenotyping and high-throughput screening, and accessions with desirable lipid profiles can be used as genetic resources for breeding programs and industrial exploitation.

Melon cultivation is of significant socioeconomic importance, especially in the northeast of Brazil. In breeding programs that employ biotechnological techniques, developing efficient methods of in vitro plant regeneration is essential for this species. The aim of this study was to develop a regeneration protocol using cotyledonary explants. The experimental design was completely randomised in a 2 x 5 factorial scheme, with two melon cultivars ('Piel de Sapo' and 'Cantaloupe') x five concentrations of 6- benzylaminopurine (BAP) (0, 4.44, 8.88, 13.32, and 17.75 μM), with five replications of five test tubes, each containing one explant. The percentage of cotyledons that formed calluses and buds, the number of buds formed per callus, and the fresh weight of the callus were evaluated 35 days after the in vitro inoculation of the explants. Data were submitted to analysis of variance, with the mean values compared between cultivars using Tukey’s test, and regression analysis between the BAP doses. No buds were formed in the culture medium containing no BAP, so it was necessary to add BAP to both cultivars. In the culture medium containing 8.88 μM BAP, 68% of the calluses in 'Cantaloupe' formed buds, while for 'Piel de Sapo', buds were formed by 12% of the calluses only. The 'Cantaloupe' cultivar recorded the highest values for fresh callus weight and number of regenerated buds per explant, indicating a better in vitro response than that of 'Piel de Sapo'.

The objective of this work was to assess sources of resistance to leafminer in melon plant germplasm and identify the most recommended variables associated with antixenosis resistance. A total of 32 genotypes were evaluated for resistance by antibiosis: larval and pupal viability, and antixenosis: mines per leaf, per plant, and per area, in choice and no-choice tests in the laboratory and through morphological characteristics. 'Festival' hybrid is the most promising source of resistance to the leafminer due to antibiosis; however, none of the evaluated genotypes show antixenosis. Mines per area is the most reliable variable to evaluate resistance to leafminers by antixenosis in melon germplasm.

Powdery mildew is one of the most challenging diseases for pumpkin and squash production, as it can cause significant losses in fruit yield and quality. The objective of this study was to evaluate sub-accessions of Cucurbita moschata from the Vegetable Germplasm Bank of the Federal University of Viçosa (BGH-UFV), in Viçosa, Minas Gerais, Brazil, for resistance to powdery mildew (Podosphaera xanthii) in young and adult plants. The physiological race of P. xanthii used in the experiments was identified using nine differentials. Eighty-seven S₀ sub-accessions were evaluated, along with two commercial cultivars of C. moschata as controls. A completely randomized experimental design with three replications was used to evaluate young plants, whereas Federer's augmented block design was used to evaluate adult plants, with seven replications as controls. Inoculation consisted of depositing spores and allowing contact between diseased and healthy plants. Evaluations were based on a subjective rating scale, with estimation of the relative area under the disease progress curve. The P. xanthii used in the experiments was identified as race 2US, making this study the first report of this variant in Minas Gerais. A significant difference was found among the C. moschata sub-accessions regarding their response to powdery mildew, indicating the existence of genetic variability and allowing for the selection of genotypes. Fifteen sub-accessions of the evaluated germplasm were identified as promising sources for developing lines resistant to powdery mildew.

Ensuring the quality attributes of cashew kernels is essential for selecting superior genotypes with agro-industrial potential. Therefore, this study characterized cashew nut accessions from the Cashew Germplasm Bank regarding kernel quality standards and identified genotypes with optimal characteristics for the industry. The characterization included key industrial indicators such as peeling efficiency, average kernel mass, class, type, and industrial yield, evaluated in 47 different accessions. Through multivariate cluster analysis and principal component analysis, the accessions revealed four distinct groups, exposing correlations among various industrial indicators. The analysis revealed a diverse genetic profile within the Cashew Germplasm Bank. A notable finding is that 80.85% of the accessions group together, displaying predominant features—easy peeling, an average mass exceeding 2.5 g, categorized as super large (SLW) and large (LW), and uniformly white-colored kernels. Correlations found include a negative relationship between kernel mass and class and positive associations between class and industrial yield, as well as between industrial yield and peeling efficiency. The study reveals substantial variability in cashew nut germplasm with respect to quality traits, highlighting its invaluable potential for identifying and selecting superior genotypes adapted for agro-industrial purposes. Particularly promising are Group 4 accessions, such as BGC632, BGC589 and BGC127, presenting attributes indicative of high-quality kernels.

Monosporascus cannonballus Pollack & Uecker and Macrophomina phaseolina Tassi (Goid) are phytopathogenic fungi responsible for causing "root rot and vine decline" in melon (Cucumis melo L.). Currently, cultural management practices are predominantly employed to control these pathogens, as the use of pesticides not only has detrimental environmental impacts but has also proven ineffective against them. These fungi have already undergone molecular characterization, and their genomes are now available, enabling the targeted search for protein targets. Therefore, this study aimed to identify novel target proteins that can serve as a foundation for the development of fungicides for effectively managing these pathogens. The genomes of M. cannonballus (assembly ASM415492v1) and M. phaseolina (assembly ASM2087553v1) were subjected to comprehensive analysis, filtration, and comparison. The proteomes of both fungi were clustered based on functional criteria, including putative and hypothetical functions, cell localization, and function-structure relationships. The selection process for homologs in the fungal genomes included a structural search. In the case of M. cannonballus, a total of 17,518 proteins were re-annotated, and among them, 13 candidate targets were identified. As for M. phaseolina, 30,226 initial proteins were analyzed, leading to the identification of 10 potential target proteins. This study thus provides new insights into the molecular functions of these potential targets, with the further validation of inhibitors through experimental methods holding promise for expanding our knowledge in this area.

Melon is a pollinator-dependent crop that relies mainly on bees to set fruits. However, manselected varieties vary in their attractiveness to flower visitors, and some flower genders and melon types may be less visited than others, harming pollination. We investigated the nectar composition of male, female and hermaphrodite flowers of 270 individuals of five commercial melons Cucumis melo (Cantaloupe, Charentais, Galia, Piel de Sapo, and Yellow), and its role in flower visit by Apis mellifera foragers. We found that melon nectar is composed mainly of sugars and amino acids such as tyrosine, phenylalanine, tryptophan, and flavonoids kaempferol3-O-neohesperidoside, luteolin hexoside, and kaempferol rhamnoside. But the amount of these chemical compounds varies among the flower genders. We also developed an accurate regression model to predict the number of bee visits to melon flowers based on the nectar composition. Our results indicate that nectar composition plays little role in bee discrimination among flowers of different melon types but is essential to the honeybee choice between flower gender. The amounts of phenylalanine (49.40%) and tryptophan (12.05%) in the nectar are related to bee preference for hermaphrodite flowers. More visits to hermaphrodite flowers contribute to setting and developing well-formed fruits, increasing productivity.

The melon is of socio-economic importance, especially in the north-east of Brazil. Obtaining homozygous lines has been an obstacle in breeding programs. In vitro androgenesis is one alternative, requiring the development of protocols for anther culture. The aim of this work was to study the effect of auxins and cytokinins on callus induction in anthers of the Goldex hybrid yellow melon. Two experiments were conducted in a completely randomised design, with 25 replications. In the first experiment, in a 3 x 3 factorial scheme, the treatments comprised concentrations of 6-furfurylaminopurine - KIN (0.0, 3.0 and 6.0 mg L-1) and indolylacetic acid - IAA (0.0, 3.0 and 6.0 mg L-1), added to Murashige and Skoog (MS) medium. In the second experiment, six treatments were tested: MS with no growth regulator; MS + 0.20 mg L-1 6-benzylaminopurine (BAP); MS + 0.20 mg L-1 naphthaleneacetic acid (NAA); MS + 0.45 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D); MS + 0.20 mg L-1 BAP + 0.20 mg L-1 NAA; and MS + 0.20 mg L-1 BAP + 0.45 mg L-1 2,4-D. The following were evaluated 60 days after anther inoculation: induction percentage, oxidation intensity, colour, texture, and the area and fresh weight of the callus. The auxins (IAA, NAA and 2,4-D) and cytokinins (KIN and BAP) induce callogenesis in anthers, but only in combination, the most suitable being 0.20 mg L-1 BAP + 0.45 mg L-1 2,4-D. The calli have a beige colour, friable texture and medium oxidation, with a strong association between the fresh weight and the area.