Resumo em Inglês:

Abstract The aim of this study was to estimate genetic and phenotypic parameters associated with progenies from the recurrent selection program for grain yield in soybean. The evaluation of S0:1 progenies was in Lavras in the 2015/2016 crop year. The S0:2 progenies were evaluated in Lavras, Nazareno, and Itutinga. The S0:3 progenies were evaluated in Lavras, Ijaci, and Itutinga in the following crop years. The following traits were evaluated: days to flowering, days to full maturity, bottom pod height, plant height, lodging, and grain yield. The expected gain and gain achieved from selection, genetic correlation, and correlated response were estimated. The variance components show variability among the progenies. It was possible to obtain gains from selection for grain yield for all selection intensities (1, 5, 10, 15, 20, 25, and 30%). The variability and the high performance of the progenies indicate that implementation of the recurrent selection program can be successful.

Resumo em Inglês:

Abstract: The objective of this study was to identify self-incompatibility (S) alleles of advanced breeding selections of apple (Malus × domestica Borkh.). The S-alleles of 42 apple genotypes were analyzed by markers using allele-specific PCR amplification and amplicons digested with restriction endonucleases. Among the screened genotypes were cultivars, advanced selections, and accessions of the Apple Germplasm Bank of Epagri (Caçador, Santa Catarina, Brazil). Two S-alleles were identified in 36 genotypes, and only one S-allele was determined in the other six genotypes. In all, eleven S-alleles were identified among all the genotypes evaluated. The S3 and S5 alleles were most frequent (30.2% and 19.8%, respectively). The identification of S-alleles using molecular markers in important apple tree genotypes is useful for determination of compatible parents for breeding programs.

Resumo em Inglês:

Abstract The objective of this study was to investigate diversity, experimental conditions and dynamics of the Irrigated Rice Breeding Program of Minas Gerais - Brazil, by meta-analysis. The target traits were grain yield, plant height and days to flowering. Evaluations were based on estimates of 376 genotypes grown at three locations, in two final comparative trials, in 14 growing seasons. Stability of the overall averages of the traits plant height and days to flowering was observed, indicating an adequate plant height and medium cycle. High average yields (>5,000 kg ha-1), good experimental accuracy and genetic variability were recorded. However, the genetic variability of all traits decreased over time, indicating the need to increase genotypic diversity. The parameter estimates of the morphoagronomic traits studied in time meta-analysis indicated the dynamic nature and good accuracy of the Irrigated Rice Breeding Program of Minas Gerais.

Resumo em Inglês:

Abstract There is an apparent overvaluation in the inbreeding coefficient (IC) formula for a synthetic variety (SV) derived from a mixture of S single crosses and L lines (FSynL,SC) in Zea mays. Therefore, our goal was to derive the exact and general FSynL,SC. For the development of this SV (SynL,SC), an even number of L + 2S unrelated lines whose IC was F (0 ≤ F ≤ 1) was considered. We show that the exact and general formula for FSynL,SC is: FSynL,SC = (2L + S)(1 + F)/[4(L + S)2], and that the ICs and genotypic means of two additional synthetics developed from the same lines (one derived from (L + 2S)/2 single crosses and the other derived from the L + 2S lines) must be equal. Among these three SVs, SynL,SC shows the largest IC.

Resumo em Inglês:

Abstract Euterpe edulis is an endemic species of the Atlantic Forest that is threatened by the unsustainable exploitation of palm heart. Fruit management is an alternative to overcome this problem, promoting income generation, preserving the trees in forest remnants and motivating the implementation of farms for commercial production. In this study, the genetic diversity and structure of four natural populations of E. edulis were evaluated using microsatellite markers and six morphological fruit traits, analyzed with and without the REML/BLUP method. The longitudinal diameter had the strongest influence on the differentiation of genotypes. The genetic differentiation among populations was low and inbreeding was detected within populations among sites. Molecular and morphological data indicated high genetic diversity in the E. edulis populations. The REML/BLUP analysis increased the accuracy of morphology-based estimates of genetic diversity, thus contributing to improve breeding strategies for fruit quality and genetic conservation by use in E. edulis.

Resumo em Inglês:

Abstract: This study aimed to evaluate half-sibling progenies for developing breeding strategies and to select mate clones with adventitious root competence, required for vegetative propagation by mini-cuttings. For rooting, single-bud mini-cuttings of 2 cm length were treated with indolebutyric acid at 2000 mg L-1. At 60 days of cultivation, the mini-cuttings were evaluated for percentages of survival and rooting, number and mean length of the three largest roots, and number of rooted mini-cuttings per mini-stump. These data were analyzed considering the mixed model described for a completely randomized design, an environment, half-sibling progenies, and a single plant per plot, by using the SELEGEN-REML/BLUP software. The 50 genotypes with the highest number of rooted mini-cuttings were selected. The genetic gain was 48.41% for the number of rooted mini-cuttings per mini-stump. Selection for adventitious rooting based on the number of rooted mini-cuttings can be used in mate breeding programs for vegetative propagation by mini-cuttings.

Resumo em Inglês:

Abstract The aim of this study was to investigate genetic control of the traits number of days to flowering (NDF) and number of days to maturity (NDM) in a cowpea cross. Genetic parameters were estimated in segregating and non-segregating generations of a cross between two contrasting cowpea genotypes (MNC05-828C-1-9-1 × MNC04-792F-146). No evidence for maternal effect was found for either trait. Broad and narrow sense heritability estimates were above 50%, allowing genetic gains from selection of plants in the F2 generation. High significance of additive gene effects and low contribution of dominance and epistatic effects were detected for both traits. The estimated number of genes controlling the traits was around 4 for NDF and 5 for NDM. The results suggest that early-maturing cowpea self-fertilized cultivars can be developed through standard breeding approaches, meeting the demands of modern agricultural systems for more crop seasons per year and mechanized harvesting.

Resumo em Inglês:

Abstract Lint and fuzz are the two types of fiber that develop on cotton seeds. Lint is an economically important fiber used in the textile industry. Fuzz fibers remain attached to seeds, and reducing the amount of fuzz could improve ginning efficiency. The Gossypium arboreum accession PI 615733 from the United States Department of Agriculture cotton germplasm collection showed the fuzzless trait, where no fuzz fibers were observed on seeds. Accession PI 615733 was crossed with the fuzzy seeded G. arboreum accession PI 529729 to develop an F2 population. Seeds from F1 plants showed no fuzz fiber. For the F2 population of 409 plants, 239 plants were classified as fuzzless and 170 were classified as fuzzy. These data support a two-gene model with incomplete dominance. A greater understanding of the genetic mechanisms controlling fiber development on cotton seeds could contribute to breeding efforts to improve lint fiber yields and quality.

Resumo em Inglês:

Abstract Phenological characteristics and yield potential in eight promising peach hybrids from selection based on fruit quality were studied in this paper. The hybrids flowered from late March to mid-April, and fruit ripened from late August to late September. The FS3, FS4, and FS7 hybrids had the highest density of flower buds. The initial fruit set was quite high (73.9%) and the final fruit set was much lower (32.2%). Fruit weight ranged from 129.8 g (FS4 hybrid) to 178.1 g (FS7 hybrid). The FS3 and FS7 hybrids had the highest yield per 1 m of shoot length (3.5 kg), and the FS2 hybrid had the highest yield per tree (25.3 kg) and the highest yield efficiency (0.30 kg cm-2). The FS2, FS3, and FS7 hybrids stood out based on yield potential. They are good candidates for release as new high-yielding peach cultivars or for use in further breeding efforts.

Resumo em Inglês:

Abstract Forest fragmentation in the Cerrado biome exposes the tree species Myracrodruon urundeuva to the risk of extinction. Thus, the objective of the study was to evaluate silvicultural characteristics related to wood quality, based on genetic parameters estimated in two M. urundeuva progenies from natural populations, assessed in Bauru-SP (PBAU) and Selvíria-MS (PSEL), 31 years after planting. The genetic parameters were estimated according to the REML/BLUP (Restricted maximum likelihood/Best Linear Unbiased Prediction) method using a mixed linear model. The progeny tests detected genetic variation. In PSEL, more positive genetic correlations and a greater number of clusters were observed. Based on the heartwood/sapwood ratio, a higher genetic gain was predicted for PBAU, and for the basic wood density, the genetic gain of the populations was approximately the same. Consequently, the areas of the two progeny tests may be used as future seed orchards to ensure wood quality and long-term ex situ conservation.

Resumo em Inglês:

Abstract: ‘BRS FS307’ is a common bean cultivar with mulatto grain developed for the Northeast of Brazil. Presents the following characteristics: cycle semi-early, yield potential of 4.145 kg ha-1 and a mean yield of 2.703 kg ha-1, i.e., 13.9% higher than that of the control cultivars (BRS Marfim and BRS Agreste).

Resumo em Inglês:

Abstract IMA 5801B2RF is a medium to short season cultivar with high fiber yield potential. The genes Bt cry1Ac and cry2Ab confer resistance to Lepidoptera and cp4-epsps confers tolerance to the herbicide glyphosate. The key feature of this new cultivar is resistance to ramularia leaf spot and root-knot nematode.

Resumo em Inglês:

Abstract The cultivars BRS Careca, BRS Fartura, BRS Duquesa, BRS Curinga, and BRS Golias of Theobroma grandiflorum are characterized by high levels of fruit production and diverse sources of resistance to witches’ broom disease. These cultivars are recommended for replacing the tree canopy of low yielding genotypes or forming new orchards.

Resumo em Inglês:

Abstract The wheat cultivar UTF 25 is recommended for wheat-growing regions 1 and 2 of Paraná and Santa Catarina states. It has a good disease resistance, early cycle, and high grain yield potential, with an average yield of 3.511 kg ha-1. It is classified as bread wheat with white flour.