Repeatability and harvest numbers in selecting sugarcane clones

Os objetivos deste trabalho foram estabelecer estimativas dos coeficientes de repetibilidade (r) e determinar a previsibilidade (R2) e o número de medições necessárias das características toneladas de colmos por hectare, toneladas de sacarose no caldo da cana por hectare e teor de sacarose dos colmos, pol porcento cana, em genótipos de cana-de-açúcar. O delineamento experimental utilizado foi o de blocos casualizados, com três repetições em quatro experimentos e quatro repetições nos demais experimentos. As estimativas de repetibilidade foram obtidas pelos métodos estatísticos da análise de variância, componentes principais com base na matriz de correlações e análise estrutural (correlação, r – médio). As estimativas dos coeficientes de repetibilidade revelaram valores muito semelhantes. A repetibilidade média geral nas três características foi superior a 0,60, demonstrando regularidade do desempenho dos genótipos nas várias medições (cortes) e confiabilidade na discriminação genotípica superior a 87%. Verificou-se, nas três características, a necessidade do emprego de no mínimo três cortes, para que a seleção possa ser praticada com previsibilidade do valor real do genótipo acima de 80%.This work aimed at the establishment of the repeatability coefficients (r), determination of the predictability degree (R2) and the needed measurement numbers for tons of cane per hectare, percentage of pol (sucrose) in the juice of cane and tons of pol in the juice of cane per hectare in sugarcane genotypes. A randomized block experimental design, with three replicates in four experiments and four replicates in the other experiments was used. The repeatability estimates were obtained by the statistical methods: anova; main components based on correlation matrix; and structural analysis (correlation, average r). The estimates of the repeatability coefficients showed values with very similar magnitude. The general average repeatability for those three traits was above 0.60, therefore showing regularity in the genotype performance at several measurements (cuts) and reliability in the genotype discrimination that was higher than 87%. The results showed that for those three traits there is a need for the use of, at least, three cuts so that the selection can be accomplished with predictability of a real value above 80% for the genotype

Gene Duplication in the Sugarcane Genome: A Case Study of Allele Interactions and Evolutionary Patterns in Two Genic Regions

Sugarcane (Saccharum spp.) is highly polyploid and aneuploid. Modern cultivars are derived from hybridization between S. officinarum and S. spontaneum. This combination results in a genome exhibiting variable ploidy among different loci, a huge genome size (~10 Gb) and a high content of repetitive regions. An approach using genomic, transcriptomic, and genetic mapping can improve our knowledge of the behavior of genetics in sugarcane. The hypothetical HP600 and Centromere Protein C (CENP-C) genes from sugarcane were used to elucidate the allelic expression and genomic and genetic behaviors of this complex polyploid. The physically linked side-by-side genes HP600 and CENP-C were found in two different homeologous chromosome groups with ploidies of eight and ten. The first region (Region01) was a Sorghum bicolor ortholog region with all haplotypes of HP600 and CENP-C expressed, but HP600 exhibited an unbalanced haplotype expression. The second region (Region02) was a scrambled sugarcane sequence formed from different noncollinear genes containing partial duplications of HP600 and CENP-C (paralogs). This duplication resulted in a non-expressed HP600 pseudogene and a recombined fusion version of CENP-C and the orthologous gene Sobic.003G299500 with at least two chimeric gene haplotypes expressed. It was also determined that it occurred before Saccharum genus formation and after the separation of sorghum and sugarcane. A linkage map was constructed using markers from nonduplicated Region01 and for the duplication (Region01 and Region02). We compare the physical and linkage maps, demonstrating the possibility of mapping markers located in duplicated regions with markers in nonduplicated region. Our results contribute directly to the improvement of linkage mapping in complex polyploids and improve the integration of physical and genetic data for sugarcane breeding programs. Thus, we describe the complexity involved in sugarcane genetics and genomics and allelic dynamics, which can be useful for understanding complex polyploid genomes

Sugarcane (Saccharum X officinarum): A Reference Study for the Regulation of Genetically Modified Cultivars in Brazil

Global interest in sugarcane has increased significantly in recent years due to its economic impact on sustainable energy production. Sugarcane breeding and better agronomic practices have contributed to a huge increase in sugarcane yield in the last 30 years. Additional increases in sugarcane yield are expected to result from the use of biotechnology tools in the near future. Genetically modified (GM) sugarcane that incorporates genes to increase resistance to biotic and abiotic stresses could play a major role in achieving this goal. However, to bring GM sugarcane to the market, it is necessary to follow a regulatory process that will evaluate the environmental and health impacts of this crop. The regulatory review process is usually accomplished through a comparison of the biology and composition of the GM cultivar and a non-GM counterpart. This review intends to provide information on non-GM sugarcane biology, genetics, breeding, agronomic management, processing, products and byproducts, as well as the current technologies used to develop GM sugarcane, with the aim of assisting regulators in the decision-making process regarding the commercial release of GM sugarcane cultivars

Trans-ancestry genome-wide association meta-analysis of prostate cancer identifies new susceptibility loci and informs genetic risk prediction.

Prostate cancer is a highly heritable disease with large disparities in incidence rates across ancestry populations. We conducted a multiancestry meta-analysis of prostate cancer genome-wide association studies (107,247 cases and 127,006 controls) and identified 86 new genetic risk variants independently associated with prostate cancer risk, bringing the total to 269 known risk variants. The top genetic risk score (GRS) decile was associated with odds ratios that ranged from 5.06 (95% confidence interval (CI), 4.84-5.29) for men of European ancestry to 3.74 (95% CI, 3.36-4.17) for men of African ancestry. Men of African ancestry were estimated to have a mean GRS that was 2.18-times higher (95% CI, 2.14-2.22), and men of East Asian ancestry 0.73-times lower (95% CI, 0.71-0.76), than men of European ancestry. These findings support the role of germline variation contributing to population differences in prostate cancer risk, with the GRS offering an approach for personalized risk prediction

Sugar cane seedling inoculation with Xanthomonas albilineans for breeding purpose

O principal objetivo deste trabalho foi o estudo da inoculação precoce com Xanthomonas albilineans em plântulas de cana-de-açúcar. Foram conduzidos dois experimentos em condições de estresse quanto à fertilidade do solo e disponibilidade de água: um deles na fase de plântulas e outro na fase clonal. A população inicial foi de 3.744 plântulas de doze progênies e a fase clonal incluiu 44 clones selecionados daquela população inicial. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e a análise foi feita por testes não paramétricos. A partir dos resultados obtidos foi possível estabelecer as seguintes conclusões principais: - A inoculação precoce deve ser encarada como um método que proporciona uma pressão de seleção uniforme à doença na população a ser selecionada, tanto na fase de plântula como, principalmente, na fase clonal; - A inoculação estudada reduz os custos de melhoramento uma vez que os índices de seleção nas plântulas inoculadas pode ser até 55% inferior ao das não inoculadas, devido a eliminação de genótipos suscetíveis, em sua maioria; - A recomendação de optar-se pela inoculação precoce com Xanthomonas albilineans depende da importância da doença nas condições locais e do tamanho da população a ser selecionada, pois podem ser descartados clones intermediários e ate alguns resistentes; - Em programas de melhoramento nos quais a Escaldadura-das-folhas é encarada como doença de menor importância, ou para se evitar rigor excessivo, não e recomendável a referida inoculação precoce em plântulas que serão submetidas a ambientes de estresse.The main purpose of this work was to study the early inoculation of Xanthomonas albilineans in sugar cane seedlings. Two trials were carried out under stressing conditions concerning soil fertility and water availability. They consisted of seedling stage and clonal stage, respectively. The initial population was 3744 seedlings from thirteen progenies and the clonal stage comprised 44 clones selected from the initial population. The experiments were planted in a split-plot arrangement of a complete randomized block design. From the results obtained it was possible to establish the following main conclusions: - The early inoculation must be faced as a method that provides a uniform disease se1ection pressure on the popu1ation to be screened, not on1y in the seedling stage but mainly in the clonal stage; - The studied inoculation reduces breeding costs as the selection index can be 55% lower in the inoculated seedlings than in noninoculated, due to the discard of susceptible seedlings; - The adoption of the early inoculation method with Xanthomonas albilineans depends on the importance of the disease to local conditions and the size of the population to be screened since intermediate clones can be discarted and even some resistant ones; - In breeding programs where leaf scald is faced as a minor disease or to avoid excessive rigour, seedlings under stressing conditions shouldn't be submitted to inoculation

Sugar cane seedling inoculation with Xanthomonas albilineans for breeding purpose

O principal objetivo deste trabalho foi o estudo da inoculação precoce com Xanthomonas albilineans em plântulas de cana-de-açúcar. Foram conduzidos dois experimentos em condições de estresse quanto à fertilidade do solo e disponibilidade de água: um deles na fase de plântulas e outro na fase clonal. A população inicial foi de 3.744 plântulas de doze progênies e a fase clonal incluiu 44 clones selecionados daquela população inicial. O delineamento experimental foi de blocos ao acaso com parcelas subdivididas e a análise foi feita por testes não paramétricos. A partir dos resultados obtidos foi possível estabelecer as seguintes conclusões principais: - A inoculação precoce deve ser encarada como um método que proporciona uma pressão de seleção uniforme à doença na população a ser selecionada, tanto na fase de plântula como, principalmente, na fase clonal; - A inoculação estudada reduz os custos de melhoramento uma vez que os índices de seleção nas plântulas inoculadas pode ser até 55% inferior ao das não inoculadas, devido a eliminação de genótipos suscetíveis, em sua maioria; - A recomendação de optar-se pela inoculação precoce com Xanthomonas albilineans depende da importância da doença nas condições locais e do tamanho da população a ser selecionada, pois podem ser descartados clones intermediários e ate alguns resistentes; - Em programas de melhoramento nos quais a Escaldadura-das-folhas é encarada como doença de menor importância, ou para se evitar rigor excessivo, não e recomendável a referida inoculação precoce em plântulas que serão submetidas a ambientes de estresse.The main purpose of this work was to study the early inoculation of Xanthomonas albilineans in sugar cane seedlings. Two trials were carried out under stressing conditions concerning soil fertility and water availability. They consisted of seedling stage and clonal stage, respectively. The initial population was 3744 seedlings from thirteen progenies and the clonal stage comprised 44 clones selected from the initial population. The experiments were planted in a split-plot arrangement of a complete randomized block design. From the results obtained it was possible to establish the following main conclusions: - The early inoculation must be faced as a method that provides a uniform disease se1ection pressure on the popu1ation to be screened, not on1y in the seedling stage but mainly in the clonal stage; - The studied inoculation reduces breeding costs as the selection index can be 55% lower in the inoculated seedlings than in noninoculated, due to the discard of susceptible seedlings; - The adoption of the early inoculation method with Xanthomonas albilineans depends on the importance of the disease to local conditions and the size of the population to be screened since intermediate clones can be discarted and even some resistant ones; - In breeding programs where leaf scald is faced as a minor disease or to avoid excessive rigour, seedlings under stressing conditions shouldn't be submitted to inoculation

Evolution of the potential productivity of the main sugarcane varieties grown in the State of São Paulo in the last fifty years

No presente trabalho procurou-se, através de ensaios de campo, mensurar o incremento em produtividade proporcionado pelas variedades melhoradas de cana-de-açúcar no Estado de São Paulo. Para compor os ensaios escolheram-se variedades de importância nesse Estado, da década de 40 até a primeira metade dos anos 90, que, cronologicamente foram: Co290, Co419, CB41-76, IAC48-65, NA56-79, SP70-1143, SP71-1406 e SP71-6163, além da RB72454, que está adquirindo proeminência, e RB835089, em início de adoção. Os viveiros de mudas foram instalados a partir de setembro de 1992, submetendo-se os colmos inicialmente ao tratamento térmico por 52?C por 30 minutos para eliminar o efeito do raquitismo-da-soqueira (Clavibacter xyli subsp. xyli). Os ensaios foram instalados nos meses de março e abril de 1994, em três municípios de regiões representativas da cultura: Santa Bárbara D'Oeste, Araras e Jardinópolis. Instalou-se ainda um experimento para determinação da curva de maturação das variedades, em Araras. Além da obtenção dos dados diretamente ligados à produção agroindustrial conduziram-se os seguintes acompanhamentos complementares: medições de falhas em cana-planta e soca, perfilhamento, avaliação de sintomas de ferrugem, medição da altura dos colmos, avaliação da intensidade de florescimento e de chochamento. As avaliações de falhas em cana-planta e cana-soca, forneceram dados que são coerentes com o perfil de brotação que as variedades contemporâneas, incluídas nos ensaios, apresentam em lavoura comercial. Partindo das melhores para as piores variedades para essa característica, a ordem foi a seguinte: SP70-1143, NA56-79, IAC48-65, CB41-76, SP71-1406, Co290, RB835089, RB72454, SP71-6163, Co419. Quanto às curvas de maturação, a variedade NA56-79 foi a mais precoce, enquanto as variedades SP70-1143 e RB72454 superaram as demais quanto aos teores de sacarose no final de safra, confirmando o perfil das mesmas. Quanto aos rendimentos agrícolas a intensidade de ferrugem (Puccinia melanocephala H. & P. Syd), doença de aparecimento recente no Brasil influenciou o posicionamento relativo entre as variedades, prejudicando variedades suscetíveis em Santa Bárbara D'Oeste, onde a intensidade de sintomas foi maior. A diferença a favor da variedade mais produtiva, RB835089 (altamente resistente à ferrugem), e de liberação mais recente, em relação à mais antiga, Co290, foi de 23% para toneladas de colmos para hectare (TCH) e 36% para toneladas de pol por hectare (TPH). Considerando-se as diferenças a favor, para os mesmos parâmetros, entre a variedade RB835089 e a menos produtiva, SP71-6163, obteve-se valores de 104% para TCH e 112% para TPH. Em ordem decrescente de produtividade as variedades se posicionaram para TCH na seguinte forma: RB835089, RB72454, SP70-1143, Co290, CB41-76, Co419, NA56-79, IAC48-65, SP71-1406 e SP71-6163. Quanto à TPH, seguindo o mesmo critério, a ordem foi a seguinte: RB835089, RB72454, SP70-1143, Co419, Co290, NA56-79, IAC48-65, CB41-76, SP71-1406 e SP71-6163. Conclui-se que o melhoramento genético têm logrado propiciar ganhos de produtividade com novas variedades, e que a alteração de ambiente, especialmente pela incidência de novas doenças, pode levar à degenerescência de variedades.The aim of this research was to determine productivity increase achieved by growing genetically improved sugarcane (Saccharum spp.) varieties in the State of São Paulo in the last fifty years. Ten expressively grown varieties in this state from the fourties until the first half of the ninities were chosen to install three experiments. Chronologically the varieties were the following: Co290, Co419, CB41-76, IAC48-65, NA56-79, SP70-1143, SP71-1406 and SP71-6163, besides RB72454, which is becoming prominent, and RB835089, which is beguining to be adopted by the growers. The nurseries used for planting were first stablished in September of 1992, the initial stalks were submitted to hot-water treatment for 52?C/30 min. with the objective of eliminating the ratoon stunting disease effect (Clavibacter xyli subsp. xyli). The experiments were set in March and April, 1994 in Santa Bárbara D'Oeste, Araras and Jardinópoiis, Counties which present characteristics represent the main traditional sugarcane planting area. In Araras, another field experiment was set to determine the varieties maturation curve. Besides those data which directly compose agroindustrial productivity, the following complementary evaluations were performed: failure in germination of plant cane and ratoon, tillering, rust (Puccinia melanocephala H. & P. Syd) incidence, stalk height, flowering and pithing. Data on germination failure in both plant cane and ratoon were valuable parameters representing ratooning performance of those sugarcane varieties included in the experiments, when grown in commercial fields. Regarding to that parameter the following order, from the best variety to the worst one, was observed: SP70-1143, NA56-79, IAC48-65, C841-76, SP71-1406, Co290, R8835089, R872454, SP71-6163, Co419. Based on the maturation curve it can be concluded that NA56-79 was the best early-maturing variety; the varieties SP70-1143 and RB72454 presented the highest sugar content at the end of the harvesting season. These data conform to the known characteristics of those varieties. Concerning cane yield, rust incidence degree played a major role in the relative ranking between the varieties, decreasing the yield of those susceptible ones in Santa Bárbara D'Oeste, were the disease occurred more intensively, as expected. The most productive variety, RB835089, which is highly resistant to rust produced 23% more tons of cane per hectare and 36% more tons of sugar per hectare than Co290, the most ancient variety of the studied period. Differences between RB835089 and the least productive variety, SP71-6163, were 104% and 112% in tons of cane and tons of sugar per hectare respectively. In decreasing order, concerning productivity in tons of cane per hectare, the following ranking was observed: R8835089, RB72454, SP70-1143, Co290, C841-76, Co419, NA56-79, IAC48-65, SP71-1406 and SP71-6163. Concerning tons of sugar per hectare, and adopting the same criterion, the following order was observed: RB835089, RB72454, SP70-1143, Co419, Co290, NA56-79, IAC48-65, CB41-76, SP71-1406 and SP71-6163. Based on these data it can be concluded that the recently improved sugarcane varieties have presented better yields as compared to the formerly grown varieties, even after changes in the environment induced by the onset of rust