Resumo em Inglês:

Abstract Glutathione S-transferases (GSTs) are proteins synthesized in plants and responsible for their tolerance to environmental stresses. However, little information is available on the GST gene family of sweet potato, a globally important crop. The genetic evolution of GSTs in sweet potato remains unclear. The present study investigated the GST gene family in sweet potato by transcriptomic and comparative genomic analyses. A total of 51 GSTs were identified. Gene expression analysis showed differential expression patterns of the GSTs between two investigated varieties. Some GST expression levels were either up- or downregulated under oxidative, salinity and drought stresses. The results of the investigation provided new insights on the GST gene family in sweet potato, which may further the understanding of the roles of these genes in regulating abiotic stresses.

Resumo em Inglês:

Abstract Capsicum is represented by peppers and sweet peppers and comprises a group with remarkable genetic variability. Different cultivated Capsicum peppers of Brazil were evaluated by using CMA3 and DAPI specific fluorochromes. There was high polymorphism of highly GC-rich CMA heterochromatic bands among the analyzed species, ranging from six (BAGC 114; C. annuum) to 26 blocks (BAGC 81; C. baccatum). Heterochromatin percentage ranged from 3.14% (BAGC 114; C. annuum) to 8.72% (BAGC 81; C. baccatum), corroborating the variation in the number of heterochromatic bands, particularly those distributed in the terminal and subterminal regions of the chromosomes. The information reported in this paper supports the cytogenetic characterization of the domesticated peppers accessions belonging to the Capsicum Germplasm Active Bank of the Federal University of Piauí (BAGC-UFPI). Moreover, the present data helped to better understand the karyotype features of peppers and provide additional information that could contribute to the improvement and maintenance of Capsicum genetic breeding programs.

Resumo em Inglês:

Abstract The objective of this study was to establish populations to start the breeding program of three species of Corymbia that are not widely planted in Brazil yet. To this end, basic density, bark content and growth of seedlots/provenances were evaluated three years after planting. The experiments consisted of 14 treatments for Corymbia citriodora subsp. variegata (CCV), 15 for C. maculata (CM), and five for C. henryi (CH). The species exhibited high survival, indicating adaptation to the Cwa climate while average coefficients of determination of seedlots exhibited intermediate values. The CCV from the Richmond Range (28º 55’ S) exhibited the highest productivity. The mean annual increment was low (22 to 26 m3ha-1), but the basic density (573 to 613 kg m-³) was high compared to the standard for eucalypts in Brazil. The bark content was close to 15% and varied between and within species.

Resumo em Inglês:

Abstract Angular leaf spot (ALS), caused by the fungus Pseudocercospora griseola, is one of the most important foliar fungal diseases in common bean (Phaseolus vulgaris L.). The search for new sources of resistance to ALS is a promising activity in common bean breeding programs. In this study, the reaction of 416 germplasm accessions from the Universidade Federal de Lavras (UFLA) to P. griseola (race 63-63, the most important and most aggressive race) was assessed under greenhouse conditions (plants in the V2 stage, fully developed unifoliolate leaves). We identified 102 (24.5%) resistant and 314 (75.5%) susceptible accessions. Among the resistant lines, more than half are Carioca grain type lines. This study characterizes the resistance of a wide collection of common bean genotypes. The identification of new accessions resistant to P. griseola is an important step in common bean breeding programs. These lines can continually be incorporated in backcrosses to obtain cultivars resistant to ALS.

Resumo em Inglês:

Abstract Soybean (Glycine max L.) is one of the four most important crops in the world. The creation of new commercial varieties is a long-term activity that requires from seven to eight years from the beginning of the cross design up to registration for commercialization of cultivars. Rapid generation advance (RGA) is a technique that consists of controlling external factors that affect plant growth with the aim of shortening the sowing to harvest cycle. In the present study, an optimized method is described that can accelerate soybean breeding by means of RGA using inexpensive facilities and that can be easily applied by breeders. Our breeding method uses a modified cold storage chamber fitted with fluorescent lamps delivering a 12/24 h light photoperiod, while temperature is set at 24 °C. This method allows development of up to 5 generations per year instead of the 1-2 generations currently possible under field or greenhouse conditions.

Resumo em Inglês:

Abstract Bacterial pustule is an important soybean disease caused by Xanthomonas citri pv. glycines, but information about genetic resistance to this pathogen is scarce. This study aimed to investigate soybean genetic resistance to bacterial pustule in the flowering stage through association analysis, characterization of candidate SNP markers, and identification of protein-coding genes potentially regulating defense processes. Therefore, 109 soybean cultivars genotyped with a 6k Illumina platform were assessed for disease severity. A genome-wide analysis revealed a total of 13 SNPs significantly associated. Through protein annotation, we identified three markers located inside the coding regions of uncharacterized protein LOC100779077, histone-lysine N-methyltransferase SUVR4, and ABC-transporter B family member-9. Nucleotide polymorphism on the first two of these markers produces a non-synonymous polymorphism with polarity shift from hydrophobic to polar amino acid. It is convenient to prioritize these three candidate markers for validation procedures with the purpose of using them in marker-assisted soybean breeding programs.

Resumo em Inglês:

Abstract Human consumption of vegetable soybeans is increasing, and consequently, breeding programs need to be encouraged and optimized. Therefore, there is a need to understand the relationship between the traits evaluated in the R6 (full seed) and R8 (full maturity) stages and estimate genetic divergence. At two sites and two crop seasons, we evaluated 42 progenies (F6 generation) from crosses between vegetable soybean genotypes and three commercial cultivars. In general, we found significant coincident correlations between environments. Positive and significant correlations between pod width (PWR6) and hundred-seed weight (HSW) and between PWR6 and hundred-pod weight (HPW) suggest the possibility of replacing the labor-intensive process of obtaining HSW and HPW by estimating PWR6, which is faster and easier to apply. The unweighted pair-group method arithmetic average analysis allocated soybean genotypes into six major clusters. Furthermore, information from the present work may guide practical actions in breeding programs.

Resumo em Inglês:

Abstract Diallel designs are widely used in plant breeding to select parents and to study trait inheritance. The present work aimed to present a method to evaluate two divergent groups of parents, in which one group is used as a tester of the contrasting group. Each parent is crossed with a balanced mixture of seeds from the parents of the other group, and the parents and topcrosses are experimentally evaluated. Two groups of ten inbred maize lines were used to obtain intergroup topcrosses and biparental crosses in a diallel scheme. The data were subjected to analysis of variance and parameter estimation using the two models. The results showed the reliability of the method for the evaluation of lines and prediction of means of hybrid populations and can be recommended when the number of parents to be evaluated is large, making it difficult to evaluate biparental crosses in a diallel scheme.

Resumo em Inglês:

Abstract Tomato is the second most important vegetable crop in the world after potato. Its production is hindered by fungal and viral diseases. Control of these diseases requires a significant investment that represents up to 40% of the production costs. Marker-assisted gene pyramiding is a powerful breeding tool which allow the rapid constitution of breeding lines with broad spectrum of resistance against diseases. Nevertheless, the accuracy and rapidity of introgression of genes of interest are some of the most critical barriers to successful application. In this paper, we use a simple and rapid method that combines duplex PCR for two important virus resistance genes (i.e., Sw-5 and Tm-22) and uses the linkage between genes Tm-22 and Forl to speed the introgression of these resistance genes into a “Pomodoro di Sorrento” tomato line. The method was used through six generations of backcrossing followed by three generations of selfing and resulted in a homozygous resistant line.

Resumo em Inglês:

Abstract BRS Deni is a super-sweet corn open-pollinated variety, developed and released by the Brazilian Agricultural Research Corporation (Embrapa) that combines high yield and good ear and grain quality and lower production costs. The grain can be consumed fresh or canned.