Resumo em Inglês:

Abstract The objective of this research was to select orange-fleshed sweet potato clones with high stability, yield, and β-carotene content in different planting seasons, using a selection index. Joint analysis of experiments and analysis of responsiveness and stability by the GGE biplot method were performed for the variables yield, dry matter percentage, and root flesh color. The variables yield, dry matter, color and stability were used to estimate a selection index. The GGE biplot analysis indicated that there are differences among clones in stability for Yield. However, the percentage of dry matter and color of the roots show low interaction in the different environments. Because of that, stability for yield was included in the selection index, together with yield, dry matter, and root orange color intensity. Finally, the selection index based on stability, yield, dry matter percentage and root color was efficient in the selection of a new biofortified sweet potato cultivar.

Resumo em Inglês:

Abstract Although maize is one of the main crops in the Northeast region, yield is still considered low when compared to other regions. One of the main solutions to increasing yield is the selection of cultivars adapted to the conditions of the Northeast region. Thus, the present study aims to use the Bayesian segmented regression model to evaluate the adaptability and stability of maize. The experiment was set up in a randomized block design with two repetitions, where 25 maize hybrids were evaluated in different states. Initially, the analysis of variance was performed. Then, the Bayesian approach of the segmented regression method was used to select the hybrids regarding adaptability and stability. There was a difference between the genotypes indicated using the a priori distribution and those indicated by the minimally informative a priori distribution. Hybrids 20A55HX, 2B433HX, 2B512HX, and P2830H were considered ideal for the Northeast region.

Resumo em Inglês:

Abstract Adaptation of photoperiod-sensitive japonica rice varieties from long-day (LD) to short-day (SD) conditions is impeded by their extremely early flowering in response to photoperiod change, but the genetic factor underlying this is still elusive. We detected mutations in Hd1 in Zhenjing2400 through gene mapping and sequencing analysis. Genome resequencing of the varieties Zhenjing2400 and Jiahe218 identified single nucleotide polymorphisms (SNPs) in the other flowering-related genes Ehd1, SDG725, OsCOL15, DTH2, and DTH7. We constructed recombinant inbred lines (RILs) derived from a cross between Zhenjing2400 and Jiahe218, and selected homozygous lines with these six genes. We established that photoperiod insensitivity is caused by a defective Hd1 gene. In addition, the effect of Hd1 and Ehd1 on heading date was stronger than that of the other four genes. Measurements of agronomic traits and quality traits in homozygous lines demonstrated the superiority of the hd1 ehd1 genotype for eating quality and photoperiod-insensitive high yield.

Resumo em Inglês:

Abstract The objective of this work was to select black oat genotypes using the MGIDI for simultaneous selection, comparing it with the Smith-Hazel index. The experiment was carried out in Frederico Westphalen/RS and Pato Branco/PR, in a randomized block design, with three replications, with 9 genotypes tested. Days from emergence to flowering and maturation; cutting and plant height; number of tillers; panicle length; tiller, plant, panicle, panicle seed mass, green and dry; and seed yield were obtained. MGIDI selected the genotypes UFSMFW 2-01 and UFSMFW 2-04 for Frederico Westphalen and UFSMFW 2-07 and UFSMFW 2-04 for Pato Branco, which varied compared to the Smith-Hazel index in both environments. MGIDI was efficient in selecting the best black oat genotypes, showing desirable selection gains for most traits.

Resumo em Inglês:

Abstract The Rpi-chc1 gene confers resistance to late blight (LB) in the wild South American species Solanum chacoense. The goal of this study was to enhance our insight into polymorphism of this gene in the genus Solanum, which is the source of valuable donors of resistance to LB. To this end, we analyzed 122 accessions of the working collection, consisting of potato cultivars, complex interspecific hybrids, and representatives of 11 wild Solanum species. We studied the polymorphism of the region of this gene that encodes the most polymorphic LRR domain. As a result, in the species S. chacoense, S. berthaultii, S. tuberosum, S. microdontum, and S. maglia we found previously unknown variants of the Rpi-chc1 gene, which differ in their amino acid sequence from both the functional and non-functional variant of the Rpi-chc1 gene. Therefore, the function of these homologues cannot be unambiguously predicted, but must be further studied.

Resumo em Inglês:

Abstract The aim of this study was to evaluate the genetic variability and performance of the agronomic traits of wheat cultivars in the southern region of Minas Gerais for the purpose of choosing parents for a rainfed wheat breeding program. We evaluated 78 wheat cultivars in two locations in Minas Gerais regarding different agronomic traits. The statistical analyses were carried out using Henderson’s mixed-model approach. The genetic values of the cultivars were predicted, and the heritabilities and accuracies were estimated for selection of cultivars. The cultivar × location interaction was decomposed into its simple and complex fractions. The genetic and environmental correlations between the traits were estimated, and selection was made for multiple traits using the sum of the standardized variables (Z-index). The genetic variance was significant for all the traits, and the cultivar × location interaction was significant. By the Z-index, 15 wheat cultivars more adapted were identified.

Resumo em Inglês:

Abstract This study was conducted to test the significance of adding row and column factors in the frequentist and Bayesian models used in the evaluation of a population of Passiflora edulis, as well as selecting promising genotypes to form the next generation. The following parameters were evaluated: number of fruits, yield, fruit weight, transverse fruit diameter, longitudinal fruit diameter, pulp percentage, skin thickness and total soluble solids. For the Bayesian model, two priors were considered, namely, inverse gamma and a priori distribution with extended parameters. The model with a priori distribution with extended parameters showed lower root mean square error and higher correlation coefficient between observed and predicted values than the inverse gamma model. Furthermore, for a selection intensity of 37%, the mixed and Bayesian models selected practically the same progenies in both experiments. The use of the 5-fold cross-validation technique indicated that both tested models were efficient.

Resumo em Inglês:

Abstract Papaya is a nutritious fruit cultivated worldwide under suitable climate conditions. This plant is polygamous, bearing female, male, and hermaphrodite sex types determined by sex chromosomes XX, XY, and XYh, respectively. In this paper, a molecular sex determination of papaya var. ‘Maradol’ was carried out based on PCR and specific primers. Specific molecular markers resulted in sixty-nine hermaphrodites and twenty-one female plants, matching 100% to the flower morphology. Nevertheless, since the summer stressing conditions rose in the greenhouse, sex reversal to male phenotype was observed in 43% of hermaphrodite plants due to high-temperature conditions. A specific male marker could not detect that change, supporting the proposal that sex reversal is caused by harsh environmental conditions aimed at epigenetic modification and genes related to hormones. Our study demonstrates the effectiveness of molecular sex determination and the importance of controlling the growing requirements of papaya to avoid sex reversal.

Resumo em Inglês:

Abstract The hybrids UENF N01, N02 and N03 have enhanced nitrogen-use efficiency, particularly in terms of N responsiveness, which makes them ideal for low-input cultivation. Even under abiotic stress, popping expansion is not reduced, indicating these hybrids for growth in the N and NW of Rio de Janeiro State.

Resumo em Inglês:

Abstract SCSBRS126 Dueto is a late-maturing high yield performing cultivar released by Epagri/Embrapa/Udesc. It has high tillering capacity, but poor resistance to lodging, medium resistance to blast, with long, slender grains and good sensory/cooking traits, and it has lower sterility under cold stress at microsporogenesis/anthesis and under heat at anthesis.

Resumo em Inglês:

Abstract IAC Herculândia is a Coffea canephora cultivar multiresistant to Meloidogyne exigua, M. incognita, and M. paranaensis to be used as a rootstock for Coffea arabica cultivars. It is a synthetic cultivar resulting from recombination among the clonal cultivars IAC WG, IAC FEBS, IAC PM, IAC LCCBF, and IAC ARM.

Resumo em Inglês:

Abstract IAC VR211 and IAC VM211 were developed for growing in Brazil with the aim of responding to the domestic and export market. The cultivars have a mean cycle of 85 days and yield potential of 2,191 kg ha-1 for IAC VR211 and 1,603 kg ha-1 for IAC VM211.