Search

California pistachio growers have traditionally grown only one female cultivar (‘Kerman’) and one male pollenizer (‘Peters’). Starting in 2005, the UC breeding program released several improved cultivars, which are being planted on increasing acreage — and tested now under commercial conditions at multiple sites over multiple years. We conducted six experimental trials in the San Joaquin Valley to evaluate the performance of the UC cultivars ‘Gumdrop’, ‘Golden Hills’ and ‘Lost Hills’ and their associated UC male pollenizers ‘Famoso’, ‘Randy’ and ‘Tejon’ against the performance of the traditional pair, ‘Kerman’ and ‘Peters’. The new cultivars demonstrated a range of earlier bloom and harvest dates than ‘Kerman’ and some improved nut quality characteristics, such as a higher percentage of split, in-shell nuts. Results indicate that by growing the new female cultivars and synchronous pollenizers, producers can avoid the peak harvest period for ‘Kerman’, when equipment and processing facilities are limited, and maintain or improve their yield and nut quality.

Resumo: Este estudo analisou a estrutura populacional de ovinos deslanados do núcleo de conservação do estado do Ceará, Brasil. Os parâmetros populacionais foram estimados com base nos dados genealógicos de indivíduos das raças Santa Inês (SI), Somalis (SO) e Morada Nova (MN), nascidos entre os anos de 2001 e 2014. Os parâmetros estimados foram: número de gerações completas equivalentes (GCE), intervalo entre gerações (IEG), número de fundadores (Nf), número efetivo de fundadores (fe), número efetivo de ancestrais (fa), coeficiente de endogamia (F) e índice de contribuição genética (ICG). O GCE médio foi de 1,82, 2,78 e 1,52 para SI, SO e MN, respectivamente. O IEG foi próximo entre as raças, 3,67 anos em média. O Nf para SI, SO e MN foi igual a 225, 194 e 153, respectivamente. As razões fe/fa foram distantes de 1 nas três populações, o que indica ocorrência de gargalo genético, principalmente para SO. Os coeficientes médios de endogamia foram de 1,81%, 0,78% e 0,78% para SI, SO e MN, respectivamente. O ICG foi de 3,32, 5,38 e 2,87 para SI, SO e MN, respectivamente. Os parâmetros populacionais estimados apontam que parte da genética original desses rebanhos foi perdida, principalmente na população da raça Somalis. [Population structure analysis in sheep without wool in the conservation nucleu]. Abstracts: This study evaluated the population structure of sheep without wool from the conservation nucleus in Ceará State, Brazil. Population parameters were estimated on genealogical records of Santa Ines (SI), Somali (SO,) and Morada Nova (MN) breeds, that were born between 2001 and 2014. The following estimates were obtained: number of complete generation equivalents (GCE), generation intervals (IEG), number of founders (Nf), effective number of founders (fe), effective number of ancestors (fa), inbreeding coefficient (F), and genetic contribution index (ICG). Average GCE was 1.82, 2.78, and 1.52 for SI, SO, and MN respectively. Mean IEG was similar between breeds, 3.67 years. The Nf was 225, 194, and 153 for SI, SO, and MN respectively. The fe/fa ratios were different to 1, which is an indication of genetic bottleneck, mainly for SO. The average inbreeding coefficients were 1.81%, 0.78%, and 0.78% for SI, SO, and MN respectively. The ICG was 3.32, 5.38, and 2.87 for SI, SO, and MN respectively. Estimated population parameters indicate that part of the genetics of these breeds was lost, mainly in Somalis. Made available in DSpace on 2020-02-17T18:13:33Z (GMT). No. of bitstreams: 1 cnpc2020Analisedaestrutura.pdf: 705746 bytes, checksum: 41b3c667bd43340725e8c1ed751a757c (MD5) Previous issue date: 2020

The objective of the present work was the molecular characterization of 11 parents and 101 hybrid progenies of conilon coffee, obtained through diallel crosses from the breeding program of the Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural (Incaper, ES, Brazil). The analyses were performed with 18 Simple Sequence Repeat (SSR) molecular markers, obtaining a total of 32 alleles. SSR markers were classifi ed as moderately informative (PIC = 0.37), being effi cient in characterizing individuals. High genetic diversity was verifi ed in the 112 genotypes, based on the greater values of observed heterozygosity about to the expected heterozygosity (0.55 and 0.44, respectively), negative values for the fi xation index (F) (-0.14), and the formation of distinct groups by UPGMA. These results indicate high genetic variability among the conilon coffee genitors, which remained similar and persisting in the progenies. The average dissimilarity between parents was 0.29 and between progenies 0.34. The progenies 38 and 40 and the parent P11 were considered the most divergent in the study. The genetic variability found can be explored in the genetic breeding of the conilon coffee and guide crossings between diversifi ed and compatible genetic materials, for the composition of novel cultivars for the state of Espírito Santo. Made available in DSpace on 2021-08-11T16:05:14Z (GMT). No. of bitstreams: 1 Molecular-characterization-2021.pdf: 1325066 bytes, checksum: 831f1c9b5a3e8adf022553169fe4e4d8 (MD5) Previous issue date: 2021

Genome-wide selection (GWS) has been becoming an essential tool in the genetic breeding of long-life species, as it increases the gain per time unit. This study had a hypothesis that GWS is a tool that can decrease the breeding cycle in Jatropha. Our objective was to compare GWS with phenotypic selection in terms of accuracy and efficiency over three harvests. Models were developed throughout the harvests to evaluate their applicability in predicting genetic values in later harvests. For this purpose, 386 individuals of the breeding population obtained from crossings between 42 parents were evaluated. The population was evaluated in random block design, with six replicates over three harvests. The genetic effects of markers were predicted in the population using 811 SNP's markers with call rate = 95% and minor allele frequency (MAF) > 4%. GWS enables gains of 108 to 346% over the phenotypic selection, with a 50% reduction in the selection cycle. This technique has potential for the Jatropha breeding since it allows the accurate obtaining of GEBV and higher efficiency compared to the phenotypic selection by reducing the time necessary to complete the selection cycle. In order to apply GWS in the first harvests, a large number of individuals in the breeding population are needed. In the case of few individuals in the population, it is recommended to perform a larger number of harvests. Made available in DSpace on 2021-12-10T12:04:23Z (GMT). No. of bitstreams: 1 Increasing-selection-gain-and-accuracy-2021.pdf: 1757494 bytes, checksum: 5b0fa15ac4d6d60a97f1f3fbf3d0afda (MD5) Previous issue date: 2021

The American oil palm [Elaeis oleifera (Knuth) Cortés] has pronounced importance in oil palm breeding programs. Here, a germplasm bank (GB) of E. oleifera plants collected in the Amazon rainforest in Brazil was submitted to single nucleotide polymorphism (SNP) marker identification, selection, and use, aiming to characterize genetic diversity and population structure and to design a core collection (CC). Five hundred and fifty-three plants from 206 subsamples, collected at 19 localities spread throughout six geographic regions, were submitted to genotyping-by-sequencing analysis. A set of 1,827 high-quality SNP markers was then selected and used to run the genetic diversity and population structure analysis. The genetic diversity found is of moderate degree, and probably only a small portion of the species diversity is represented in the collection. The possible reason for that is the collecting strategy used, which collected subsamples only around the most prominent watercourses in the region. The average degree of genetic differentiation among subsamples is very high, indicating the presence of high interpopulation differentiation. The collection showed a low level of endogamy. The low average gene flow found indicates that genetic isolation caused by drift is occurring, and there is a need to review the conservation strategy. A set of 245 SNPs distributed throughout all 16 chromosomes was used to design CC based on maximizing the strategy of diversity. The optimal adjustment of the validated parameters, maintained while taking fewest subsamples, led to the choice of a model containing 20% of the entire collection as the ideal to form the CC. Made available in DSpace on 2021-01-13T09:05:49Z (GMT). No. of bitstreams: 1 American-oil-palm-2020.pdf: 2338289 bytes, checksum: bd094acf8939bfe8fed55b69aece920c (MD5) Previous issue date: 2020

Wheat (Triticum aestivum L.) is one of the most important crops in the world. Brazil is one of the largest importers of this cereal, and wheat breeding programs are attempting to increase productivity and reduce external dependence. The objectives of this study were to quantify the spring wheat genetic gain in Brazil between 1984 and 2014 using data from multienvironment trials, and to verify if the genetic gain stagnated after the 2000s. This study used a highly unbalanced dataset containing grain yield (GY) data from 187 spring wheat trials that were performed at 25 locations between 2002 and 2015. In total, 126 cultivars, released between 1985 and 2014, were evaluated over 14 crop seasons. The cultivar evaluation indicated that there was a genetic gain in GY of 33.9 kg ha⁻¹ yr⁻¹ (r² = 0.53, P < 0.01), which represents an increase of 1.28% yr⁻¹. The dataset showed a linear regression for the genetic gain and indicates that wheat genetic gain has not stagnated in Brazil after the 2000s.

Genetic redundancy in cassava (Manihot esculenta Crantz) presents a challenge to efficient management of genetic resources. This study aimed to identify and define the ge-netic structure of duplicates in cassava germplasm from various Embrapa research units, using single-nucleotide polymorphism (SNP) markers. We evaluated 2,371 accessions with 20,712 SNPs. The identification of duplicates was performed based on multilocus genotypes (MLG), adopting a maximum genetic distance threshold of 0.05. The population structure was defined based on discriminant analysis of principal components (DAPC). A total of 1,757 unique and 614 duplicate accessions were identified. The redundancy of the collections ranged from 17% (Belém, PA/Brazil) to 39% (Petrolina, PE/Brazil), with an average of 21%. This redundancy between different research units is probably due to the historical sharing of accessions, as well as collections carried out in the same region, or even to the intense germplasm exchange between farmers with different genotype names. In terms of genetic structure, the 250 principal components explained 88 % of the genetic variation of the SNP markers and defined the hierar-chical structure of the duplicate cassava germplasm in 12 groups. Since heterotic groups have not yet been identified for cassava, crosses between accessions of the 12 DAPC groups may be promising. All MLGs were allocated within the same DAPC group, corroborating duplicate analyses yet still revealing high variability between groups that were quite distinct based on the first two discriminant functions. Our results contribute to optimizing the conservation of genetic resources, together with understanding diversity and its use in crop improvement. Made available in DSpace on 2019-07-26T01:05:19Z (GMT). No. of bitstreams: 1 Indetification2019.pdf: 383917 bytes, checksum: f897b166e953b68695c64ed637c829d6 (MD5) Previous issue date: 2019

Fusarium wilt of lettuce, caused by the soilborne fungus Fusarium oxysporum f. sp. lactucae, affects all major lettuce production areas in California and Arizona. In trials at UC Davis, we found that lettuce cultivars differ significantly in susceptibility to the disease, with some leaf and romaine types highly resistant under all test conditions. For more susceptible cultivars, disease severity is strongly influenced by inoculum levels and ambient temperature. Management of Fusarium wilt requires an integrated approach that includes crop rotation to reduce soil inoculum levels and the use of resistant cultivars during the warmest planting windows.

A Embrapa Suínos e Aves, em uma de suas linhas de pesquisa, vem desenvolvendo estudos em genômica com foco em problemas locomotores, tanto em aves como em suínos. Em aves, a variação genética normal de características de integridade óssea e os fatores genéticos associados à BCO estão sendo investigados.

Foram avaliadas e selecionadas as famílias provenientes do programa de melhoramento do tomateiro da UFU, com potencial para processamento industrial e comparados seus desempenhos com os híbridos mais utilizados pelos produtores na região de Patos de Minas. O ensaio foi conduzido na EE Fazenda Barreiro da Unilever Bestfoods Brasil, em Patos de Minas. Utilizaram-se 30 famílias de tomateiro e os híbridos Heinz 9553, Heinz 7155N2 e Hypeel 108. As Parcelas constituíram-se de linhas duplas espaçadas 0,5 m entre si, com 10 m de comprimento, irrigadas por gotejamento. O espaçamento entre as linhas duplas foi de 1,3 m e a população de 27 mil plantas por hectare. O delineamento experimental foi de blocos ao acaso, com quatro repetições. A semeadura foi realizada em 19/05/01. O rendimento de polpa mostrou correlações fenotípicas e genotípicas positivas com a produção total, produção de frutos comerciais, % de sólidos solúveis totais, coloração do suco, número de frutos maduros por planta e pH e negativa com acidez total titulável. Destacaram-se a família UFU 06 e os três híbridos comerciais. Tomato families originated from the processing tomato breeding program of the Universidade Federal de Uberlandia were evaluated and selected and compared to the performance with the most planted hybrids in Patos de Minas, Brazil. The experiment was conducted in the E. E. Barreiro, Unilever Bestfoods, in Patos de Minas. Thirty tomato families and the hybrids Heinz 9553, Heinz 7155N2 and Hypeel 108 were used. Experimental plots consisted of two lines, each one 10 m long, spaced 0,5 m from each other and irrigated with drip irrigation. The space between each double row was 1,3 m and the population of 27 thousand plants per hectare. The experimental design was a randomised complete block with four repetitions, installed on 05/19/01. The paste yield showed positive phenotypic and genotypic correlation with total fruit yield, commercial fruit yield, percentage of total soluble solids, juice coloration, number of mature fruits per plant and pH and negative correlation with the total titled acidity. Best results were observed in the family UFU 06 and in the commercial hybrids.