Genetic and biochemical strategies for regulation of L-ascorbic acid biosynthesis in plants through the L-galactose pathway.

Vitamin C (L-ascorbic acid, AsA) is an essential compound with pleiotropic functions in many organisms. Since its isolation in the last century, AsA has attracted the attention of the scientific community, allowing the discovery of the L-galactose pathway, which is the main pathway for AsA biosynthesis in plants. Thus, the aim of this review is to analyze the genetic and biochemical strategies employed by plant cells for regulating AsA biosynthesis through the L-galactose pathway. In this pathway, participates eight enzymes encoded by the genes PMI, PMM, GMP, GME, GGP, GPP, GDH, and GLDH. All these genes and their encoded enzymes have been well characterized, demonstrating their participation in AsA biosynthesis. Also, have described some genetic and biochemical strategies that allow its regulation. The genetic strategy includes regulation at transcriptional and post-transcriptional levels. In the first one, it was demonstrated that the expression levels of the genes correlate directly with AsA content in the tissues/organs of the plants. Also, it was proved that these genes are light-induced because they have light-responsive promoter motifs (e.g., ATC, I-box, GT1 motif, etc.). In addition, were identified some transcription factors that function as activators (e.g., SlICE1, AtERF98, SlHZ24, etc.) or inactivators (e.g., SlL1L4, ABI4, SlNYYA10) regulate the transcription of these genes. In the second one, it was proved that some genes have alternative splicing events and could be a mechanism to control AsA biosynthesis. Also, it was demonstrated that a conserved cis-acting upstream open reading frame (5'-uORF) located in the 5'-untranslated region of the GGP gene induces its post-transcriptional repression. Among the biochemical strategies discovered is the control of the enzyme levels (usually by decreasing their quantities), control of the enzyme catalytic activity (by increasing or decreasing its activity), feedback inhibition of some enzymes (GME and GGP), subcellular compartmentation of AsA, the metabolon assembly of the enzymes, and control of AsA biosynthesis by electron flow. Together, the construction of this basic knowledge has been establishing the foundations for generating genetically improved varieties of fruits and vegetables enriched with AsA, commonly used in animal and human feed.

Additive and Non-Additive Effects on the Control of Key Agronomic Traits in Popcorn Lines under Contrasting Phosphorus Conditions.

Phosphorus is a non-renewable natural resource that will run out of reserves in the upcoming decades, making it essential to understanding the inheritance of nutrient use efficiency for selecting superior genotypes. This study investigated the additive and non-additive effects of commercially relevant traits for the popcorn crop (grain yield-GY, popping expansion-PE, and expanded popcorn volume per hectare-PV) in different conditions of phosphorus (P) availability in two locations in Rio de Janeiro State, Brazil. Six S7 lines previously selected for P use-L59, L70, and P7, efficient and responsive; and L54, L75, and L80, inefficient and non-responsive-were used as testers in crosses with 15 progenies from the fifth cycle of intrapopulation recurrent selection of UENF-14, with adaptation to the North and Northwest regions of Rio de Janeiro State. Using the Griffing diallel analysis, P use efficiency was predominantly additive in the expression of PE, and non-additive effects were prominent for GY and PV. For obtaining genotypes that are efficient for phosphorus use, it is recommended that heterosis with parents that provide additive gene accumulation for PE be explored.

Meiosis in Polyploids and Implications for Genetic Mapping: A Review.

Plant cytogenetic studies have provided essential knowledge on chromosome behavior during meiosis, contributing to our understanding of this complex process. In this review, we describe in detail the meiotic process in auto- and allopolyploids from the onset of prophase I through pairing, recombination, and bivalent formation, highlighting recent findings on the genetic control and mode of action of specific proteins that lead to diploid-like meiosis behavior in polyploid species. During the meiosis of newly formed polyploids, related chromosomes (homologous in autopolyploids; homologous and homoeologous in allopolyploids) can combine in complex structures called multivalents. These structures occur when multiple chromosomes simultaneously pair, synapse, and recombine. We discuss the effectiveness of crossover frequency in preventing multivalent formation and favoring regular meiosis. Homoeologous recombination in particular can generate new gene (locus) combinations and phenotypes, but it may destabilize the karyotype and lead to aberrant meiotic behavior, reducing fertility. In crop species, understanding the factors that control pairing and recombination has the potential to provide plant breeders with resources to make fuller use of available chromosome variations in number and structure. We focused on wheat and oilseed rape, since there is an abundance of elucidating studies on this subject, including the molecular characterization of the Ph1 (wheat) and PrBn (oilseed rape) loci, which are known to play a crucial role in regulating meiosis. Finally, we exploited the consequences of chromosome pairing and recombination for genetic map construction in polyploids, highlighting two case studies of complex genomes: (i) modern sugarcane, which has a man-made genome harboring two subgenomes with some recombinant chromosomes; and (ii) hexaploid sweet potato, a naturally occurring polyploid. The recent inclusion of allelic dosage information has improved linkage estimation in polyploids, allowing multilocus genetic maps to be constructed.

Rapid adjustments of migration and life history in hemisphere-switching cliff swallows.

Many aspects of bird migration are necessarily innate.1 However, the extent of deterministic genetic control, environmental influence, and individual decision making in the control of migration remains unclear.2-8 Globally, few cases of rapid and dramatic life-history changes resulting in novel migration strategies are known. An example is latitudinal trans-hemispheric breeding colonization, whereby a subpopulation suddenly begins breeding on its non-breeding range.9-13 These life-history reversals demand concomitant changes in the timing of migration, feather molt, and breeding if the population is to remain viable.13 Cliff swallows, Petrochelidon pyrrhonota, are long-distance migrants that breed in North America and spend the non-breeding season mostly in South America.14 However, in 2015, a small population switched hemispheres by breeding successfully in Argentina,9 over 8,000 km from the nearest potential source, after presumably failed attempts.15,16 This provided a unique chance to characterize the early mechanisms of change in migratory behavior and phenology and to assess the possibility of double breeding. We tracked cliff swallows with geolocators following their second and fourth breeding seasons in Argentina, documenting inverted seasonality, three new migratory patterns and non-breeding areas (North America, Mesoamerica, and South America), and a shift of molt phenology by approximately 6 months, all possibly arising within a single generation. These birds did not practice migratory double breeding, although some spent the boreal summer in the traditional breeding range. Our data show that fundamental phenological changes occurred very rapidly during colonization and that phenotypic plasticity can underlie profound changes in the life histories of migratory birds.

Emergence and epidemics of a new disease in Araguaia Valley: anthracnosis of cotton caused by Colletotrichum truncatum, varietal reaction and difficulties of chemical control / Epidemias da antracnose do algodoeiro no Vale do Araguaia causada por Colletotrichum truncatum reação de cultivares e dificuldades de controle químico

Cotton culture (Gossypium hirsutum L.) is trending in an upward expansion amidst Brazilian "cerrado". Due this growth, new pathosystems are growing in incidence on tropical fields in the region of Araguaia Valley - MT. Surveys and material collection were conducted out in production areas on two counties (Bom Jesus - MT and Canarana ­ MT), both regions represents a total amount of 50.000 hectares of cultivated area. The region also is characterized by succession areas previously sowed with soybean plants (main cover crop season). Previously surveys revealed the incidence of target spot (Corynespora cassiicola), ramularia spot (Ramularia areola) and cercosporiosis (Cercospora gossypii). Disease incidence is commonly observed on several crop management methods and cultivars. Due to a reduction in efficacy of chemichal control by fungicides spray programs, this disease is increasing and spreading in a faster rate in production areas with previous harvested soybean at the biggest soybean producer group in the world (Bom Futuro). Plants on field were selected due to differences in symptoms, and isolation methods were carried out on PDA (potato-dextrose-agar) before "in vitro" pathogenicity tests conducted on seedlings, detached leaves and bolls (growth chamber conditions of 23°C / photoperiod of 12 hours). After Colletotrichum dextructor sp. pathogenicity confirmation, bioassays were carried out with several different fungicide's groups (i.e. registered for usage on Brazilian jurisdiction). This test consisted of the employment of a solution with 500 ppm of each different fungicide/a.i. that is applied on infected bolls and detached leaves who were inoculated with the target pathogen (concentration of 104 conidia per mL). This test was followed by an infection (%) evaluation during 10 days of incubation. The incidence/prevalence index (%) was also evaluated at different parts of the plant (lower, middle, and upper canopy) on different cultivars/genotypes (130-150 days after sowing). A standard level of control by different fungicides, ranged between 0 to 100% of control. Two groups of cultivars/genotypes were separated after differences on resistance response, one with susceptible traits (FM 985 GLTP) and other with partial resistance traits. No immunity response was observed. We suggest that new efficacy tests should be carried out with combination of varietal response (resistance or tolerance) combined with other chemical fungicides for better understanding of synergism or positive interaction. Valuable information will highlight the best association for greater varietal response and yield against this necrotrophic pathogen (higher B0 ­ initial inoculum) survival during successive years of rotation main crop (cotton x soybean). Isolated spray of benzimidazoles, cupric (except cuprous oxide) and triple associations with triazoles or triazolinthione (prothioconazol) combined with strobilurins and carboxamides should be wisely administrated to manage this disease due to low efficiency (below 50%). New field and laboratory essay must be carried out to input data about resistance risk and clarify damage levels on leaves and bolls impacting yield.

O algodoeiro Gossypium hirsutum L. está em plena expansão no Brasil em área da Bahia e Mato Grosso. Em função dessa expansão novos patossistemas podem ocorrer nas áreas tropicais na região do Vale do Araguaia - MT. Foram realizados levantamentos em áreas de produção nos municípios de Bom Jesus ­ MT e Canarana ­ MT nas áreas de expansão da cultura que atingem mais de 50.000 ha. Nessa região o cultivo é realizado após o cultivo da soja em uma sucessão. São comuns nessas áreas a mancha alvo (Corynespora cassiicola), mancha de ramularia (Ramularia areola) e a Cercosporiose (Cercospora gossypii). Devido as falhas nos programas, com diferentes fungicidas de controle foram realizadas inspeções nas áreas de produção do grupo Bom futuro em diferentes cultivares e sistemas de manejo. Em função da sintomatologia diferenciada e constando-se ser um novo problema foram realizados isolamentos em BDA (batata-dextrose-ágar) e realizados testes de patogenicidade em plântulas, folhas e maçãs destacadas na temperatura de 23o Celsius e regime alternado de luz do dia por 12 horas. Após a confirmação da patogenicidade em plântulas, folhas destacadas, maçãs ou capulhos para Colletotrichum truncatum foram realizados bioensaios com todos os grupos de fungicidas registrados no Brasil. Foram usada a concentração de 500 (mg.kg-1) ppm dos ingredientes ativos, de cada formulação ou fungicida. Após a pulverização dos fungicidas foi em seguida inoculado o patógeno na concentração de 104 conídios por ml. Avaliou-se 10 dias após a incubação a porcentagem de infecção nas folhas destacadas, assim como o percentual de infecção em cada maça inoculada pelo patógeno. Confirmou-se um nível de controle pelos diferentes fungicidas variando de 0 a 100 %, tanto para folhas, como para maças destacadas. Também foi avaliado o índice de prevalência (%), considerando os três terços da planta (terço inferior, médio e superior), em diferentes genótipos em condições de campo na fase final da produção das plantas (130-150 dias). Os genótipos foram suscetíveis (FM 985 GLTP) e muitos genótipos apresentaram resistência parcial. Nenhum genótipo foi imune ao patógeno. Sugere-se a revisão dos programas e manejo com fungicidas visando alternar os melhores ingredientes ativos para o novo patógeno, associado aos genótipos como maior resistência varietal, uma vez que o patógeno pode sobreviver de um ano para o outro em sementes e restos culturais. Fungicidas benzimidazóis, cúpricos (exceto óxido cuproso), benzimidazol + triazol + estrobilurina e carboxamida + triazolintiona + estrobilurina devem ser usados com cautela no controle da doença em função da sua baixa eficiência (abaixo de 50 %), em condições de laboratório (folhas e frutos ­ maçãs destacadas).

Lysenko and the Screwworm Fly-When Politics Interferes with Science and Public Health.

In the One Health scenario, a deep understanding of the dynamics potentially threatening the development and implementation of useful pest and vector management tools is of key importance. The New World screwworm fly, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), is characterized by a wide host range. It acts as an important agent of myiasis in humans and warm-blooded animals in the Neotropics, and has been eliminated from a wide region through genetic methods. Of note, Serebrovsky had already proposed in 1940 the principles of autocidal control by the translocation of segments between two chromosomes, but his work was negated by Lysenko, based on the negation of Mendelian genetics. This entomological case study emphasizes the danger of politics interfering with science, a still contemporary hot issue. The negation of global warming or current pandemics are further examples of this noxious influence.

Genetics and genomics of uniformity and resilience in livestock and aquaculture species: A review.

Genetic control of residual variance offers opportunities to increase uniformity and resilience of livestock and aquaculture species. Improving uniformity and resilience of animals will improve health and welfare of animals and lead to more homogenous products. Our aims in this review were to summarize the current models and methods to study genetic control of residual variance, genetic parameters and genomic results for residual variance and discuss future research directions. Typically, the genetic coefficient of variation is high (median = 0.27; range 0-0.86) and the heritability of residual variance is low (median = 0.01; range 0-0.10). Higher heritabilities can be achieved when increasing the number of records per animal. Divergent selection experiments have supported the feasibility of selecting for high or low residual variance. Genomic studies have revealed associations in regions related to stress, including those from the heat shock protein family. Although the number of studies is growing, genetic control of residual variance is still poorly understood, but big data and genomics offer great opportunities.

Morphoagronomic characters and partial resistance t o soybean rust in early soybean genotypes / Caracteres morfoagronômicos e resistência parcial à ferrugem asiática em genótipos precoces de soja

Soybean crop, despite the technological evolution, did not reach an average of 4,000 kg ha-1 in Brazil due to the factors of climate, nutritional and soil fertility, genetics and phytosanitary problems. Among them is the rust-soy disease of soybean, caused by the fungus Phakopsora pachyrhizi Syd. & Syd., one of the most severe, with damage up to 100%. Among the management strategies are the use of early genotypes, use of preventive fungicides and cultivars with partial resistance and tolerant to phytopathogen. To obtain resistant cultivars, six dominant genes that condition vertical (qualitative) resistance, have already been reported in the literature, but the stability of this type of resistance is not durable. Therefore, the identification of genotypes that can be used as sources of horizontal (quantitative) resistance is essential to increase the longevity of the cultivars launched in the Brazilian market. This work aimed to evaluate the resistance of 12 soybean genotypes to the pathogen and yield responses. This work was developed at Fazenda do Glória, in Federal University of Uberlândia (UFU), located in the city of Uberlândia, MG, Brazil. In the agricultural year 2015/2016 an experiment was carried out with subplots with or without fungicide Azoxistrobina + Benzovindiflupyr and subsubplots related to the evaluation position in the plant. There were 12 early-cycle genotypes, 10 from the UFU germplasm laboratory (LAGER), a commercial susceptible control, and a knownresistant LAGER control. They were outlined in randomized blocks with four replicates. The experimental plots were represented by two rows of 6 m x 0.5 m, and the 2.5 m 2 area consisted of the two central rows, eliminating 0.5 m at each end of the plot. The LAGER-210 and LAGER-216 genotypes were selected for crop and use value (CUV) studies because they showed partial resistance to rust, short cycle, good morphoagronomic characteristics and higher yields.

A soja, mesmo com a evolução tecnológica, não atingiu ainda uma média de produção no Brasil de 4.000 kg ha-1. Isto é devido aos fatores climáticos, nutricionais, genéticos e fitossanitários. Dentre eles está a doença ferrugem-asiática da soja, causada pelo fungo Phakopsora pachyrhizi Syd. & Syd., uma das mais severas, com danos de até 100%. Dentre as estratégias de manejo estão o uso de genótipos precoces, uso de fungicidas de forma preventiva e cultivares com resistência parcial ao fitopatógeno. Para a obtenção de cultivares resistentes, seis genes dominantes, que condicionam a resistência vertical (qualitativa), já foram relatados na literatura, mas a estabilidade desse tipo de resistência não é durável. Portanto, a identificação de genótipos que possam ser utilizados como fontes de resistência horizontal (quantitativa) é primordial para aumentar a longevidade das cultivares lançadas no mercado brasileiro. Este trabalho teve como objetivo avaliar a resistência de 12 genótipos de soja frente ao patógeno e respostas à produtividade. O presente trabalho foi desenvolvido na Fazenda do Glória, na Universidade Federal de Uberlândia (UFU), localizada no município de Uberlândia, MG, Brasil. No ano agrícola 2015/2016 foi conduzido um experimento com subparcelas com ou sem fungicida Azoxistrobina + Benzovindiflupyr e subsubparcelas relacionadas à posição de avaliação naplanta. Foram 12 genótipos de ciclo precoce, sendo 10 provenientes do laboratório de germoplasma da UFU (LAGER), uma testemunha comercial suscetível e uma testemunha do LAGER conhecidamente resistente, delineados em blocos casualizados, com quatro repetições. As parcelas experimentais foram representadas por duas fileiras de 6 m x 0,5 m, sendo que a área útil de 2,5 m² constituiu-se pelas duas fileiras centrais, eliminando-se 0,5 m em cada extremidade da parcela. Os genótipos LAGER-210 e LAGER-216 foram selecionados para estudos de valor de cultivo e uso (VCU) por apresentarem resistência parcial à ferrugem, ciclo curto, boas características morfoagronômicas e maiores produtividades.

BOLA-DRB3 gene polymorphisms influence bovine leukaemia virus infection levels in Holstein and Holstein × Jersey crossbreed dairy cattle.

Bovine leukemia virus (BLV) infections, causing persistent lymphocytosis and lethal lymphosarcoma in cattle, have reached high endemicity on dairy farms. We observed extensive inter-individual variation in the level of infection (LI) by assessing differences in proviral load in peripheral blood. This phenotypic variation appears to be determined by host genetics variants, especially those located in the BoLA-DRB3 MHCII molecule. We performed an association study using sequencing-based typed BOLA-DRB3 alleles from over 800 Holstein and Holstein × Jersey cows considering LI in vivo and accounting for filial relationships. The DBR3*0902 allele was associated with a low level of infection (LLI) (<1% of circulating infected B-cells), whereas the DRB3*1001 and DRB3*1201 alleles were related to a high level of infection (HLI). We found evidence that 13 polymorphic positions located in the pockets of the peptide-binding cleft of the BOLA-DRB3 alleles were associated with LI. DRB3*0902 had unique haplotypes for each of the pockets: Ser13 -Glu70 -Arg71 -Glu74 (pocket 4), Ser11 -Ser30 (pocket 6), Glu28 -Trp61 -Arg71 (pocket 7) and Asn37 -Asp57 (pocket 9), and all of them were significantly associated with LLI. Conversely, Lys13 -Arg70 -Ala71 -Ala74 and Ser13 -Arg70 -Ala71 -Ala74 , corresponding to the DRB3*1001 and *1201 alleles respectively, were associated with HLI. We showed that the specific amino acid pattern in the DRB3*0902 peptide-binding cleft may be related to the set point of a very low proviral load level in adult cows. Moreover, we identified two BOLA-DRB3 alleles associated with a HLI, which is compatible with a highly contagious profile.

Integration of resistant cultivars and fungicides in the control of ramularia leaf spot and yield of cotton / Integração de cultivares resistentes e fungicidas no controle da mancha de ramularia (Ramularia areola) e produtividade do algodoeiro

O algodoeiro é uma das principais espécies cultivadas na região Centro-oeste do Brasil e há grande utilização de fungicidas para o controle da mancha de ramulária (MR), uma doença de relevante importância econômica.  O objetivo deste trabalho foi avaliar o efeito da integração de cultivares considerados resistentes (C) e tratamentos fungicidas (TF) no controle da MR e produtividade de algodoeiro cultivado em Chapadão do Sul, MS. Foi utilizado o delineamento de blocos ao acaso, com quatro repetições e arranjo fatorial de 3 (C) x 7 (TF). As avaliações consistiram na estimativa da área abaixo do progresso da doença total (AACPDT), na parte inferior (AACPDI) e superior (AACPDS) das plantas. Da mesma forma, estratificou-se a produtividade de algodão em caroço e o índice de micronaire nas fibras. Os dados foram submetidos ao teste F e as médias comparadas por meio do teste de Scott-Knott a 1% de probabilidade. Houve interação significativa entre C e TF para AACPDT, AACPDI e AACPDS, menos para produtividade e índice micronaire. Constatou-se que houve: maior produtividade e severidade da mancha de ramulária na região inferior das plantas; não houve diferença de produtividade entre as cultivares; houve efeito de C e TF no índice de micronaire; e os TF não influenciaram significativamente a severidade nas cultivares FMT 705 e FMT 709, resistentes à MR. Estes resultados recomendam a integração de TF e C para o controle da MR do algodoeiro.(AU)

Cotton is one of the main species grown in the Midwest region of Brazil and there is a high use of fungicides to control Ramularia leaf spot (RLS), an important disease caused by Ramularia areola. The objective of this study was to evaluate the integration of resistant cultivars (C) and fungicides treatments (FT) in the RLS control and yield of cotton grown in Chapadão do Sul, MS, Brazil. The experimental design consisted of randomized blocks with four replications and factorial arrangement of C (3) x FT (7). The whole plant area under the disease curve progress (AUDCP-WP) and from the lower (AUDCP-B) and upper (AUDCP-U) half of the plant were all evaluated. Likewise, cotton yield and micronaire index of the fibers were stratified. Obtained data was submitted to the F test and mean values were compared by the Scott-Knott test at 5% probability. There was a significant interaction between C and FT for AUDCP-WP, AUDCP-B and AUDCP-U but not for yield and micronaire index. Higher productivity and severity of RLS in the lower half was observed; there was no difference in productivity between cultivars; effect of C and FT in the micronaire index; and FT had no significant effect on disease severity in the resistant cultivars FMT 705 and FMT 709. These results recommend the integration of FT and C to control RLS of cotton.(AU)

Avaliação biológica de machos esterilizados por radiação gama, para utilização em programas de controle populacional de Aedes aegypti (DIPTERA: CULICIDAE) / Biological evaluation of sterilized males by gamma radiation for use in the Aedes aegypti (Diptera: Culicidae) population control programs

Este estudo avaliou o desempenho biológico e reprodutivo de machos de Aedes aegypti esterilizados por radiação gama e seu potencial para uso no controle da espécie, através da técnica do inseto estéril (TIE). A eficácia de esterilização de diferentes doses de radiação gama, 30, 40 e 50 Gy, foi avaliada em machos irradiados (MI) na fase de pupa. O seu efeito sobre a longevidade e competitividade de acasalamento dos MI, sobre a fecundidade e fertilidade das fêmeas acasaladas com estes machos, bem como de fêmeas também irradiadas (FI), foram parâmetros analisados. Os testes de competitividade foram conduzidos em gaiolas teladas (2 X 2 m) em condições simuladas de campo, onde foram liberados machos irradiados e machos não irradiados (MNI), nas seguintes proporções: 5:1, 10:1 e 15:1. Os resultados revelaram que o fitness biológico e reprodutivo dos mosquitos são afetados pela radiação, de modo que os efeitos são diretamente proporcionais a dose de radiação utilizada. O parâmetro de longevidade apresentou diferenças significativas, tanto quando os MI foram analisados de forma individual quanto em grupo. Para a maior dose, MI e FI viveram em média 19,6 ± 2,2 dias e 25,8 ± 2,2 dias, respectivamente, enquanto que no grupo controle, estes valores foram de 24,9 ± 2,5 dias e 30,4 ± 2,5 dias...

This study evaluated the biological and reproductiv e performance of Aedes aegyptimales sterilized by gamma radiation and its potential for use in controlling the species through the Sterile Insect Technique (SIT). The sterilization efficacy of different doses of gamma radiation, 30, 40 and 50 Gy, was assessed in irradiated males (IM) in the pupal stage. The direct effects of gama radiation on the longevity and competitiveness of IM, as well as the effect on the fecundity and fertility of females mated with these males, and also irradiated females (IF), were analyzed. The competitiveness was examined by tests conducted in large cage (2 x 2 meters) in semi field conditions where irradiated males (IM) and non-irradiated males (NIM) were released in the following proportions: 5:1, 10:1 and 15:1. The results revealed that the biological and reproductive fitness of the mosquitoes are affected by radiation, so that the effects are directly proportional to the radiation dose. The longevity parameter showed significant differences...

Reação de cultivares de trigo à ferrugem da folha e mancha amarela e responsividade a fungicidas / Reaction of wheat cultivars to leaf rust and yellow spot and responsiveness to fungicides

Com o objetivo de avaliar a reação de cultivares de trigo à ferrugem da folha, causada por Puccinia triticina, e mancha amarela, causada por Drechslera tritici-repentis, e sua responsividade ao controle químico com fungicidas, foi conduzido experimento de campo durante os invernos de 2009 e 2010, Itaara-RS. As cultivares avaliadas foram 'FCEP 51', 'FCEP 52', 'CD 114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' e 'OR Pampeano'; na safra 2010, a cultivar 'CD 114' foi substituída pela OR Quartzo. Os tratamentos avaliados foram: P1 - testemunha sem aplicação de fungicida; P2 - fempropimorfe (560g ha-1 de i.a.); P3 - azoxistrobina + ciproconazol (60+24g ha-1 de i.a.); e P4 - piraclostrobina + metconazol (60+97,5g ha-1 de i.a.). Após a segunda aplicação, efetuaram-se avaliações semanais de severidade das doenças, cujos dados foram utilizados para o cálculo da Área Abaixo da Curva de Progresso da Doença (AACPD). Também foram determinados a produtividade e o peso do hectolitro. No que se refere à suscetibilidade às doenças, as cultivares estudadas apresentaram respostas distintas de um ano para o outro. Para ferrugem, o comportamento mostrou-se similar em ambos os anos, enquanto que, para mancha amarela, houve variação. Quanto à resposta ao controle químico, ocorreram variações de acordo com o patógeno e com o grau de suscetibilidade das cultivares. O uso integrado de resistência genética e controle químico mostrou-se mais efetivo para ferrugem da folha.

Aiming to evaluate the susceptibility of wheat cultivars to leaf rust and yellow spot and their responsiveness to chemical fungicides, two field trials were carried out, during 2009 and 2010 winter's. The cultivars evaluated were: 'FCEP 51', 'FCEP 52', 'CD114', 'FCEP Campo Real', 'FCEP Cristalino', 'FCEP Nova Era', 'OR Marfim', 'OR Abalone', 'OR Safira' and 'OR Pampeano'. In 2010, the 'CD 114' cultivar was replaced by Quartzo. The treatments were: P1 - Without fungicide application; P2 - fenpropimorph (560g ha-1 of a.i.); P3 - azoxystrobin + cyproconazole (60+24g ha-1 of a.i.) and; P4 - pyraclostrobin + metconazole (60+97,5g ha-1 of a.i.). The severity of leaf rust and tan spots were assessed weekly after the second spray and the data were utilized to calculate the Area Under the Disease Progress Curve (AUDPC). The grain yield and hectoliter weight were assessed at the harvest time. Regarding to susceptibility to diseases, the cultivars had different responses from one year to another. For leaf rust, the behavior was found to be similar in both studies, while for yellow spot was variation. Regarding to the chemical control, response variations were observed according to the pathogen and the susceptibility's degree of the cultivars. The integrated use of genetic resistance and chemical control was more effective for leaf rust.

Genetic Control of Mosquitoes: population suppression strategies / Controle genético de mosquitos: estratégias de supressão de populações

Over the last two decades, morbidity and mortality from malaria and dengue fever among other pathogens are an increasing Public Health problem. The increase in the geographic distribution of vectors is accompanied by the emergence of viruses and diseases in new areas. There are insufficient specific therapeutic drugs available and there are no reliable vaccines for malaria or dengue, although some progress has been achieved, there is still a long way between its development and actual field use. Most mosquito control measures have failed to achieve their goals, mostly because of the mosquito's great reproductive capacity and genomic flexibility. Chemical control is increasingly restricted due to potential human toxicity, mortality in no target organisms, insecticide resistance, and other environmental impacts. Other strategies for mosquito control are desperately needed. The Sterile Insect Technique (SIT) is a species-specific and environmentally benign method for insect population suppression, it is based on mass rearing, radiation mediated sterilization, and release of a large number of male insects. Releasing of Insects carrying a dominant lethal gene (RIDL) offers a solution to many of the drawbacks of traditional SIT that have limited its application in mosquitoes while maintaining its environmentally friendly and species-specific utility. The self-limiting nature of sterile mosquitoes tends to make the issues related to field use of these somewhat less challenging than for self-spreading systems characteristic of population replacement strategies. They also are closer to field use, so might be appropriate to consider first. The prospect of genetic control methods against mosquito vectored human diseases is rapidly becoming a reality, many decisions will need to be made on a national, regional and international level regarding the biosafety, social, cultural and ethical aspects of the use and deployment of these vector control methods.

Ao longo das duas últimas décadas, morbidade e mortalidade da malária e dengue e outros patógenos tem se tornado cada vez mais um problema de Saúde Pública. O aumento na distribuição geográfica de seus respectivos vetores é acompanhada pela emergência de doenças em novas áreas. Não estão disponíveis drogas específicas suficientes e não há vacinas específicas para imunizar as populações alvo. As medidas de controle de mosquitos atuais falharam em atingir os objetivos propostos, principalmente devido à grande capacidade reprodutiva dos mosquitos e alta flexibilidade genômica. O controle químico se torna cada vez mais restrito devido a sua potencial toxicidade aos seres humanos, mortalidade de organismos não alvos, resistência a inseticida além de outros impactos ambientais. Novas estratégias de controle são necessárias. A técnica do inseto estéril (SIT) é um método de supressão populacional espécie específico e ambientalmente amigável, baseia-se na criação em massa, esterilização mediante irradiação e liberação de um grande número de insetos machos. Liberar insetos carregando um gene letal dominante (RIDL) oferece uma solução a muitas limitações impostas pela técnica do inseto estéril (SIT) que limitaram sua aplicação em mosquitos e ainda assim mantém suas características de ambientalmente amigável e espécie específica. A natureza auto-limitante de mosquitos estéreis tende a deixar alguns empecilhos para uso no campo, de certa forma, menos desafiadores quando comparados a sistemas auto-propagação, característicos de estratégias de substituição de população. Sistemas auto-limitantes estão mais próximos para uso no campo, portanto pode ser apropriado considerá-lo primeiro. A perspectiva de métodos de controle genéticos contra mosquitos vetores de doenças que acometem humanos está rapidamente se tornando uma realidade, muitas decisões terão de ser tomadas em âmbito nacional, regional e internacional com relação a aspectos étnicos, sociais, culturais e de biossegurança para o uso e liberação destes métodos de controle de vetores.

Identification of leaf rust resistance genes in selected Argentinean bread wheat cultivars by gene postulation and molecular markers

Leaf rust, caused by Puccinia triticina Eriks. is a common and widespread disease of bread wheat (Triticum aestivum L.), in Argentina. Host resistance is the most economical, effective and ecologically sustainable method of controlling the disease. Gene postulation helps to determine leaf rust resistance genes (Lr genes) that may be present in a large group of wheat germplasm. Additionally presence of Lr genes can be determined using associated molecular markers. The objective of this study was to identify Lr genes that condition leaf rust resistance in 66 wheat cultivars from Argentina. Twenty four differential lines with individual known leaf rust resistance genes were tested with 17 different pathotypes of leaf rust collected from Argentina. Leaf rust infection types produced on seedling plants of the 66 local cultivars were compared with the infection types produced by the same pathotypes on Lr differentials to postulate which seedling leaf rust genes were present. Presence of Lr9, Lr10, Lr19, Lr20, Lr21, Lr24, Lr25, Lr26, Lr29, Lr34, Lr35, Lr37, Lr47 and Lr51 was also determined using molecular markers. Eleven different Lr genes were postulated in the material: Lr1, Lr3a, Lr3ka, Lr9, Lr10, Lr16, Lr17, Lr19, Lr24, Lr26, Lr41. Presence of Lr21, Lr25, Lr29, and Lr47 could not be determined with the seventeen pathotypes used in the study because all were avirulent to these genes. Eleven cultivars (16.7 percent) were resistant to all pathotypes used in the study and the remaining 55 (83.3 percent) showed virulent reaction against one or more local pathotypes. Cultivars with seedling resistance gene combinations including Lr16 or single genes Lr47 (detected with molecular marker), Lr19 and Lr41, showed high levels of resistance against all pathotypes or most of them. On the opposite side, cultivars with seedling resistance genes Lr1, Lr3a, Lr3a + Lr24, Lr10, Lr3a + Lr10, Lr3a + Lr10 + Lr24 showed the highest number of virulent reactions against local...

Genetic control of the angular leaf spot reaction in common bean leaves and pods

Information about genetic control of plant reaction to pathogens is essential in plant breeding programs focusing resistance. This study aimed to obtain information about genetic control of the angular leaf spot reaction in leaves and pods from common bean (Phaseolus vulgaris L.) line ESAL 686. This line was crossed with cultivars Jalo EEP 558 (resistant), Cornell 49-242 (resistant) and Carioca MG (susceptible). Generations F1, F2 and backcrosses (BC11 and BC21) were obtained. In the dry season (2009), parents and respective populations were evaluated for angular leaf spot reaction under field conditions. Disease severity was evaluated on leaves and pods using diagrammatic scales. Severity scores were obtained and mean and variance genetic components were estimated for both. Segregation of F2 generation was analyzed for some crosses. Different genes control angular leaf spot reaction in leaves and pods. Mean and variance components showed predominance of additive effects. Heritability was high, however, was greater on pods than on leaves which indicated that leaf reaction is more influenced by the environment.

Genetic control of the angular leaf spot reaction in common bean leaves and pods

Information about genetic control of plant reaction to pathogens is essential in plant breeding programs focusing resistance. This study aimed to obtain information about genetic control of the angular leaf spot reaction in leaves and pods from common bean (Phaseolus vulgaris L.) line ESAL 686. This line was crossed with cultivars Jalo EEP 558 (resistant), Cornell 49-242 (resistant) and Carioca MG (susceptible). Generations F1, F2 and backcrosses (BC11 and BC21) were obtained. In the dry season (2009), parents and respective populations were evaluated for angular leaf spot reaction under field conditions. Disease severity was evaluated on leaves and pods using diagrammatic scales. Severity scores were obtained and mean and variance genetic components were estimated for both. Segregation of F2 generation was analyzed for some crosses. Different genes control angular leaf spot reaction in leaves and pods. Mean and variance components showed predominance of additive effects. Heritability was high, however, was greater on pods than on leaves which indicated that leaf reaction is more influenced by the environment.

Controle genético da regeneração in vitro em progênies de Eucalyptus grandis / Genetic control of in vitro regeneration of Eucalyptus grandis

Com o objetivo de avaliar o controle genético da regeneração direta in vitro a partir de plântulas de Eucalyptus grandis, foram utilizadas sementes de 10 progênies de polinização aberta da população base, origem Atherton, localizada em Anhembi, Estado de São Paulo. Vinte dias de cultivo após a germinação, 196 segmentos distais dos hipocótilos por progênie foram inoculados in vitro num Delineamento em Blocos Completos Aleatorizado Generalizado, com duas unidades experimentais por bloco e sete repetições por bloco, usando a interação blocos por progênie como estimadora do erro experimental. Após 14 semanas de cultivo, foram feitas avaliações da regeneração. Houve diferenças significativas de regeneração entre as progênies (P<0,0001) com extremos de regeneração de 11 por cento a 60 por cento. A herdabilidade no sentido restrito entre as médias das unidades experimentais do caráter foi alta (h2m=0,94), indicando que houve um forte controle genético na regeneração in vitro dentro da população. Houve também alta variabilidade dentro da amostra estudada, assim como um forte efeito do progenitor materno sobre a regeneração.

The genetic control of in vitro direct regeneration was tested on seedlings of ten open-pollinated progenies from the base population of Atherton origin of Eucalyptus grandis at University of São Paulo (Brazil). Seeds were germinated in vitro, after twenty days, distal hypocotyls segments from 196 seedlings per progeny were inoculated in culture media at Generalized Complete Randomized Block Design, with two experimental units per block and seven repetitions, using the interaction blocks by progenies as an estimate of the experimental error. At week 14 from the inoculation bud induction was evaluated. Regeneration among progenies were significantly different (P<0.0001). Regeneration varied from 11 to 60 percent. The narrow-sense heritability between means of experimental units for in vitro regeneration was height. (h2m=0.94), indicating a strong genetic control of the trait within the population and also a high maternal effect. High variability within the study sample was found.

Controle genético da regeneração in vitro em progênies de Eucalyptus grandis

The genetic control of in vitro direct regeneration was tested on seedlings of ten open-pollinated progenies from the base population of Atherton origin of Eucalyptus grandis at University of São Paulo (Brazil). Seeds were germinated in vitro, after twenty days, distal hypocotyls segments from 196 seedlings per progeny were inoculated in culture media at Generalized Complete Randomized Block Design, with two experimental units per block and seven repetitions, using the interaction blocks by progenies as an estimate of the experimental error. At week 14 from the inoculation bud induction was evaluated. Regeneration among progenies were significantly different (P 0.0001). Regeneration varied from 11 to 60%. The narrow-sense heritability between means of experimental units for in vitro regeneration was height. (h2m=0.94), indicating a strong genetic control of the trait within the population and also a high maternal effect. High variability within the study sample was found.

Com o objetivo de avaliar o controle genético da regeneração direta in vitro a partir de plântulas de Eucalyptus grandis, foram utilizadas sementes de 10 progênies de polinização aberta da população base, origem Atherton, localizada em Anhembi, Estado de São Paulo. Vinte dias de cultivo após a germinação, 196 segmentos distais dos hipocótilos por progênie foram inoculados in vitro num Delineamento em Blocos Completos Aleatorizado Generalizado, com duas unidades experimentais por bloco e sete repetições por bloco, usando a interação blocos por progênie como estimadora do erro experimental. Após 14 semanas de cultivo, foram feitas avaliações da regeneração. Houve diferenças significativas de regeneração entre as progênies (P 0,0001) com extremos de regeneração de 11% a 60%. A herdabilidade no sentido restrito entre as médias das unidades experimentais do caráter foi alta (h2m=0,94), indicando que houve um forte controle genético na regeneração in vitro dentro da população. Houve também alta variabilidade dentro da amostra estudada, assim como um forte efeito do progenitor materno sobre a regeneração.

Controle genético da regeneração in vitro em progênies de Eucalyptus grandis

The genetic control of in vitro direct regeneration was tested on seedlings of ten open-pollinated progenies from the base population of Atherton origin of Eucalyptus grandis at University of São Paulo (Brazil). Seeds were germinated in vitro, after twenty days, distal hypocotyls segments from 196 seedlings per progeny were inoculated in culture media at Generalized Complete Randomized Block Design, with two experimental units per block and seven repetitions, using the interaction blocks by progenies as an estimate of the experimental error. At week 14 from the inoculation bud induction was evaluated. Regeneration among progenies were significantly different (P 0.0001). Regeneration varied from 11 to 60%. The narrow-sense heritability between means of experimental units for in vitro regeneration was height. (h2m=0.94), indicating a strong genetic control of the trait within the population and also a high maternal effect. High variability within the study sample was found.

Com o objetivo de avaliar o controle genético da regeneração direta in vitro a partir de plântulas de Eucalyptus grandis, foram utilizadas sementes de 10 progênies de polinização aberta da população base, origem Atherton, localizada em Anhembi, Estado de São Paulo. Vinte dias de cultivo após a germinação, 196 segmentos distais dos hipocótilos por progênie foram inoculados in vitro num Delineamento em Blocos Completos Aleatorizado Generalizado, com duas unidades experimentais por bloco e sete repetições por bloco, usando a interação blocos por progênie como estimadora do erro experimental. Após 14 semanas de cultivo, foram feitas avaliações da regeneração. Houve diferenças significativas de regeneração entre as progênies (P 0,0001) com extremos de regeneração de 11% a 60%. A herdabilidade no sentido restrito entre as médias das unidades experimentais do caráter foi alta (h2m=0,94), indicando que houve um forte controle genético na regeneração in vitro dentro da população. Houve também alta variabilidade dentro da amostra estudada, assim como um forte efeito do progenitor materno sobre a regeneração.

Herança da inflorescência composta da cultivar de feijão-caupi cacheado / Inheritance of composite inflorescence of cowpea cacheado cultivar

O feijão-caupi [Vigna unguiculata (L.) Walp.] apresenta inflorescência simples. Entretanto, foram identificados dois genes mutantes recessivos ci e bp que condicionam a produção de inflorescência composta na espécie. Essa característica também foi constatada na cultivar local Cacheado. Objetiva-se com este trabalho determinar o controle genético dessa característica. Foram realizados dois cruzamentos Freezergreen x Cacheado e Bettegreen x Cacheado. Os cruzamentos e a obtenção das gerações F1, F2 e retrocruzamentos, com ambos parentais, foram realizados em casa-de-vegetação. No experimento de campo foi utilizado o delineamento de blocos casualizados com quatro repetições. Cada parcela foi representada por uma fileira de 10,0 m, com espaçamento entre fileiras de 0,80 m e dentro da fileira de 0,50 m, sendo cultivada uma planta por cova. Esse experimento foi conduzido sob irrigação por aspersão convencional, na Embrapa Meio-Norte, em Teresina, Piauí, nos anos 1998/1999. O teste de chi2 foi usado para a análise dos dados. As segregações das gerações F2 se ajustaram à proporção de 3 inflorescências simples: 1 inflorescência composta e as dos retrocruzamentos com o parental Cacheado à proporção de 1 inflorescência simples: 1 inflorescência composta. A partir desses resultados depreende-se que a inflorescência composta presente na cultivar cacheado tem herança monogênica recessiva.

Cowpea [Vigna unguiculata (L.) Walp.] presents simple inflorescence. However, two recessive mutant genes ci and bp that produce composite inflorescence were identified in cowpea. This characteristic was also observed in the brazillian local cultivar Cacheado. The aim of this work was to investigate the genetic control of the composite inflorescence of Cacheado Cultivar. Two crosses were performed Freezergreen x Cacheado and Bettegreen x Cacheado. The crosses and the F1, F2 and the backcrosses were obtained in greenhouse. In the field trial the randomized complete block design with four replications was used. Each plot was represented by a row of 10 m long with 20 plants. The spacing between rows was of the 0,80 m. The experiment was carried out in the field, under irrigation by conventional aspersion at Embrapa Meio-Norte, Teresina city, Piauí Statate, the years of 1998 and 1999. The Qui Square test was used to analyse the data. The segregation pattern in both F2 generations fitted the 3 simple inflorescences: 1 composite inflorescence ratio and the backcrosses to the Cacheado cultivar fitted the 1 simple inflorescence: 1 composite inflorescence ratio. The inheritance study showed that composite inflorescence of the Cacheado cultivar is controlled by a single recessive gene.