Sebastião Márcio de Azevedo

The tomato (Solanum lycopersicum L.) is one of the most important vegetables from an economic, social, and nutritional point of view, being widely consumed throughout the world, both fresh and processed. Due to its importance, this crop is a constant focus of genetic improvement programs that seek to develop superior genotypes, such as higher quality, yield, and disease resistance. Thus, the aim of this study was to select experimental indeterminate Italian tomato hybrids with high yield, superior fruit quality, and resistance to TSWV (tomato spotted wilt virus) via molecular markers. The trial was conducted in the municipality of Ijaci, southern Minas Gerais, Brazil. A randomized block design was used, with 16 hybrids (12 experimental and 4 commercial controls), four replications, and five plants per plot. Evaluations were carried out for yield, fruit quality, and resistance to TSWV under natural infection and through molecular markers to identify the Sw5 gene. Six experimental hybrids stood out in terms of high yield, with hybrid TO-014 being superior to the others, presenting better size and higher commercial classification. Most genotypes showed few defects, revealing good qualitative characteristics, with the exception of three hybrids (TO-004, TO-042, and TO-134), which demonstrated greater susceptibility to TSWV. Seven experimental hybrids were considered resistant to TSWV because they carry the Sw-5 gene and did not show symptoms of infection in the field. Six of these hybrids also stood out in terms of yield and fruit quality, demonstrating that resistance to the virus has a direct impact on productive characteristics.

The objective of this work was to estimate the genetic parameters and correlations of characteristics related to production and color in kale and to select the best genotypes based on REML/BLUP estimates. The experiment was carried out in a completely randomized block design, with three replicates. The treatments consisted of 34 experimental kale clones. The parameters evaluated were: total leaf yield (TLY), number of commercial leaves (NCL), average leaf mass (ALM), number of shoots (NS), chlorophyll content (CC), and colorimetric patterns of luminosity (L), chroma (C), and hue (h) of the leaves. Genetic parameters, genotypic and phenotypic correlations, and genetic values were estimated. The kale genotypes UFLA 06, UFLA 14, UFLA 16, UFLA 22, and UFLA 34 have good productive characteristics and intense green color, with high heritability. The characteristics TLY, NCL, ALM, NS, CC, and colorimetric patterns of L and C present high heritability in kale. TLY shows a positive correlation with the NCL and the ALM in kale. The genotypes UFLA 02, UFLA 04, UFLA 13, UFLA 25, UFLA 31, and UFLA 32 stand out for their productive characteristics, but not in high levels of antioxidants. The NCL presents positive correlation with the NS, which does not benefit seed production.

The objective of this work was to estimate the optimal number of harvests for the reliable selection of zucchini (Cucurbita pepo) hybrids through the repeatability coefficient. The experimental design was randomized complete blocks with 33 treatments (31 experimental hybrids and 2 commercial ones) and four replicates, with six plants per plot. Fifteen harvests were carried out. Seven morphoagronomic fruit characteristics were evaluated, and repeatability coefficients were estimated using four statistical methods. The repeatability coefficients ranged from low to moderate, regardless of the studied characteristic. For a high-precision selection (R2≥90%), a high number of evaluated harvests was required, especially for traits related to fruit yield, as follows: 30 to 54 harvests for selection based on total yield; and 43 to 83 harvests for commercial yield, which varied according to the statistical estimation method. The principal component analysis based on the covariance matrix required the least number of harvests for a satisfactory selection precision. Fifteen harvests are sufficient for a satisfactory selection of all evaluated characteristics, with a precision above 70%.

The tomato is one of the most economically, socially and nutritionally important vegetables, presenting high added value. The culture allows high profit for the producers, but it is a high risk activity due to, specially, the sensibility of some varieties to climate conditions as well as multiple plagues and diseases that attack the culture. Therefore, the search for new hybrids with more tolerance to biotic and abiotic factors is extremely important to attend to the demand of the culture’s productive chain. The objective of this work was to demonstrate the importance of multivariate and univariate techniques in evaluating the level of similarity among hybrids of the tomato plant of the salad group with the purpose of diagnosing possible groups in relation to the variables analyzed. A total of 23 hybrids of tomato from the salad group were evaluated; of those, 9 were commercial hybrids and 14 were experimental hybrids. Throughout the conduction of the experiment, the productive characters of the culture were evaluated as well as the characteristics of the fruits and the agronomic characters of the plant. For the productive characters and the characteristics of the fruits, the multiple factor analysis was performed, and the averages were compared by the Scott-Knott test. For the agronomic characters of the plant, the exploratory data analysis was used with the correspondence analysis. The commercial hybrids studied present a high degree of similarity among them, with more than 77% of the materials with strong or high similarity with the other materials. Meanwhile, for the experimental hybrids, this result is seen in only 42.86% of the materials. The experimental hybrids 3124, 3139, and 3126 present higher divergence when compared to the other materials studied. They are, therefore, recommended to increase the genetic base of the tomato plant’s breeding program.

The identification of genotypes with greater capacity for flowering and seed production is crucial for greater efficiency in the genetic improvement of the sweet potato crop. Thus, the objective of this work was to evaluate the flowering capacity and the production of botanical seeds in sweet potato genotypes. The work was carried out in the municipality of Lavras, located in the southern region of Minas Gerais, Brazil. Twenty-two sweet potato genotypes belonging to the germplasm bank of the Federal University of Lavras (UFLA) were evaluated. The characteristics evaluated were the flowering period (days), the number of viable seeds, the total weight of viable seeds, the weight of 1000 seeds and the percentage of germination. The obtained data were analyzed by means of descriptive statistics, study of correlations and analysis of main components. The sweet potato genotypes evaluated showed a high capacity for flowering and production of botanical seeds. Flowering usually starts 125 days after planting and extends on average for 72 days. Considering future recombination to promote flowering capacity, seed production and greater germination, genotypes BD-05, BD-26 and BD-44 should be prioritized.