Abstract BRS A705 is an early-maturing cultivar developed by Embrapa, recommended for irrigated cultivation. The plants have high tillering and moderate resistance to the main diseases. This cultivar has short stature, which confers a greater tolerance to lodging. It presents high yield and long and fine grains of excellent quality. A A70 earlymaturing early maturing Embrapa cultivation diseases stature lodging quality A7

Abstract BRS Pampa CL is a rice cultivar developed by Embrapa, recommended for irrigated cultivation in Rio Grande do Sul State, Brazil. It shows modern architecture, high tiller ing, early cycle, and tolerance to the imidazolinone herbicide Kifix®. It stands out for its high yield potential and excellent grain quality.

Abstract BRS A502 is an upland rice cultivar with a medium cycle, high resistance to lodging, superior yield potential and grains of excellent industrial and cooking quality. The cultivar is indicated for crop rotation and succession in areas under intensive agriculture in the main field crop regions of Brazil.

Resumo O objetivo deste trabalho foi identificar fatores ambientais com efeitos significativos sobre a interação entre genótipos e ambiente (GEI), em canade-açúcar, e produzir mapas temáticos quanto à adaptabilidade produtiva de genótipos para o estado de Goiás, Brasil, por meio do uso integrado de modelos de regressão fatorial e do sistema de informação geográfica (SIG). O estudo foi baseado na produção de açúcar recuperável (ATR), obtida de ensaios de cultivares em campo, em nove localidades. Foram utilizados 14 fatores ambientais, dos quais 11 foram divididos em 10 fases de crescimento da cultura, no total de 113 covariáveis ambientais (ECs). A seleção de ECs foi feita por sucessivas regressões lineares simples, e os respectivos coeficientes de sensibilidade genotípica foram usados para produzir os mapas de adaptabilidade. Aproximadamente 57% dos efeitos da GEI estiveram relacionados às covariáveis longitude, temperatura média na fase de brotação da cultura e temperatura máxima no início da fase de maior crescimento. Para ATR, os clones RB034128 e RB034021 apresentam adaptações produtivas específicas, e a cultivar RB034045 pode compartilhar a área de cultivo com a cultivar-testemunha RB867515.

Abstract The objective of this work was to identify environmental factors with significant effects on the genotype by environment interaction (GEI) of sugarcane, and to generate thematic maps yield adaptability of genotypes for the state of Goiás, Brazil, through the integrated use of factorial regression models and the geographic information system (GIS). The study was based on the yield of recoverable sugar (YRS) from cultivar field trials carried out in nine locations. Fourteen environmental factors were used, out of which 11 were divided into 10 crop growth phases, totaling 113 environmental covariates (ECs). The selection of ECs was done by successive simple linear regressions, and the respective genotypic sensitivity coefficients were used to generate adaptability maps. Approximately 57% of the GEI effects were related to the covariates longitude, average temperature at crop germination phase, and maximum temperature at the beginning of the phase of greatest growth. For YRS, the RB034128 and RB034021 clones show specific yield adaptations, and the RB034045 cultivar can share the growing area with the RB867515 check cultivar.

Periodic assessment of the genetic progress made in recurrent selection programs is essential for assessing the evolution of the programs and identifying the main factors that have contributed to this progress. This study aimed to estimate genetic progress in grain yield, plant height and days-to-flowering achieved in the CNA6 population of upland rice (Oryza sativa L.), after four cycles of recurrent selection; and evaluate the genetic potential of this population to generate superior inbred lines after each selection cycle. The experimental data were obtained from progeny yield trials of each recurrent selection cycle. These trials were carried out in two or three locations per cycle, and consisted of S0:2 progenies and at least three checks. Federer’s augmented block design, with one replication on location (the environment), was adopted. Results revealed genetic progress for grain yield and plant height, with total genetic gains of 375.87 kg ha−1 and -3.90 cm, respectively, during the four selection cycles. The annual relative gain observed for grain yield was 1.54 %. The genetic potential of the population was analysed by the expected proportion of superior inbred lines. The standard adopted as the limit for obtaining superior inbred lines was the average of the checks for each trait. The genetic potential for grain yield and plant height increased during the study period. For days-to-flowering, no genetic gain occurred; however, the genetic potential of the population to generate superior inbred lines for this trait was maintained after the selection cycles.

Association analysis was applied to a panel of accessions of Embrapa Rice Core Collection (ERiCC) with 86 SSR and field data from two experiments. A clear subdivision between lowland and upland accessions was apparent, thereby indicating the presence of population structure. Thirty-two accessions with admixed ancestry were identified through structure analysis, these being discarded from association analysis, thus leaving 210 accessions subdivided into two panels. The association of yield and grain-quality traits with SSR was undertaken with a mixed linear model, with markers and subpopulation as fixed factors, and kinship matrix as a random factor. Eight markers from the two appraised panels showed significant association with four different traits, although only one (RM190) maintained the marker-trait association across years and cultivation. The significant association detected between amylose content and RM190 was in agreement with previous QTL analyses in the literature. Herein, the feasibility of undertaking association analysis in conjunction with germplasm characterization was demonstrated, even when considering low marker density. The high linkage disequilibrium expected in rice lines and cultivars facilitates the detection of marker-trait associations for implementing marker assisted selection, and the mining of alleles related to important traits in germplasm.

O objetivo deste trabalho foi avaliar, por meio de análise dialélica, o potencial de dez variedades de arroz-vermelho para a implementação de um programa de melhoramento. A identificação de genitores foi feita com dez variedades, em um cruzamento dialélico completo sem recíprocos. As variedades e seus 45 cruzamentos foram avaliados nas gerações F1 e F3, quanto às suas características agronômicas, em delineamento em blocos ao acaso. Para o caráter produção de grãos, foram avaliados: a heterose do cruzamento (H), o efeito varietal (v), a heterose média (h), a heterose varietal (h) e a heterose específica (s) em cada geração, além da capacidade geral de combinação (g) dos genitores. Foram detectadas diferenças significativas entre as variedades genitoras, quanto às características agronômicas avaliadas, e foram considerados mais promissores, para a seleção de novas linhagens, os cruzamentos 'AL03/PB13' e 'PB05/PB10', em razão das estimativas favoráveis dos parâmetros relacionados à produtividade, à diversidade genética e à capacidade de combinação de seus genitores.

The objective of this work was to evaluate, using the diallelic analysis, the potential of ten varieties of red rice for the implementation of a breeding program. The identification of parents was performed with ten lendraces was performed with in a complete diallel crossing without reciprocals. The varieties and their 45 diallel crosses were evaluated in generations F1 and F3 for agronomic traits in a randomized block design. For the yield character, the following characteristics were evaluated: varietal effect, varietal heterosis and specific heterosis in each generation, plus the general combining ability. Significant differences among parents for the traits evaluated were detected; and the crosses 'AL03/PB13' and 'PB05/PB10' were considered the most promising for selection of elite lines of red rice for the favorable parameter estimates related to yield, genetic diversity and combining ability of their parents.

Os ganhos genéticos para produtividade obtidos pelo programa de melhoramento do arroz irrigado por inundação na Região Nordeste do Brasil no período de 1984 a 1993 foram estimados visando avaliar a eficiência do programa e traçar novas estratégias. Esta estimativa foi feita a partir dos dados de 59 ensaios regionais de rendimento conduzidos pelas empresas de pesquisa agropecuária do Nordeste, em cooperação com a Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão (CNPAF), Goiânia, GO. O método estatístico utilizado baseia-se em médias ajustadas por modelo linear generalizado. O ganho genético médio estimado foi de 54,9 ± 14,4 kg/ha/ano (0,8%). Nos últimos três anos houve uma tendência de interrupção dos ganhos. A pequena magnitude dos ganhos para produção nesta região podem ser atribuídos ao direcionamento do programa de geração de linhagens da Embrapa para qualidade de grãos e resistência a doenças, às diferenças ambientais existentes entre Goiânia e a Região Nordeste e ao pequeno número de ensaios conduzidos. A genealogia das linhagens foi traçada e verificou-se que os principais ancestrais são os mesmos das cultivares recomendadas. A base genética das linhagens é estreita, o que também pode estar contribuindo para a obtenção de pequenos ganhos genéticos para produtividade.

The genetic gains for yield obtained by the breeding program of irrigated rice in the Northeast Region of Brazil from 1984 to 1993 were estimated to evaluate the program efficiency. This estimation was done based on data from 59 regional field trials conducted by the Northeastern farm research institutions in cooperation with Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão (CNPAF), Goiânia, GO, Brazil. The statistical method used was based on adjusted means by generalized linear model. The estimated mean genetic gain was 54.9 ± 14.4 kg/ha-1/yr-1 (0,8%). However, in the last three years, there was a tendency of interrupting the gains. The small gain obtained for yield in the referred region may be attributed to the strategy adopted by the line breeding program of Embrapa, which has priority for grain quality and disease resistance, the environmental differences between Goiânia and the Northeast Region and the small number of trials conducted. The genealogy of the lines was traced back and it was identified that the main ancestors are mostly the same as the released varieties. The genetic base of the lines is narrow, which may be contributing to the small genetic gains obtained for yield.

Os ganhos genéticos obtidos pelo melhoramento de caracteres quantitativos podem ser estimados utilizando resultados de ensaios regionais de avaliação de linhagens e cultivares. Um novo método estatístico para esta estimativa é proposto, o qual consiste em quatro passos: a) análise conjunta da série de dados dos ensaios regionais através de um modelo linear generalizado de forma a obter as médias ajustadas dos genótipos e a matriz de covariâncias destas médias; b) para o grupo de genótipos avaliados em cada ano, cálculo da média aritmética das médias ajustadas obtidas na análise conjunta; c) comparação direta dos anos, conforme as médias aritméticas obtidas, e d) estimativa de um ganho genético médio, por regressão. Aplicando-se o método de quadrados mínimos generalizado, é calculada uma estimativa ponderada do ganho genético médio no período. Este método permite um melhor cancelamento das interações genótipo x ano e genótipo x ensaio/ano, resultando assim em estimativas mais precisas. Este método pode ser aplicado a dados desbalanceados, o que possibilita a estimativa dos ganhos genéticos em séries de ensaios multilocais de qualquer amplitude e duração.

The genetic gain obtained by breeding programs to improve quantitative traits may be estimated by using data from regional trials. A new statistical method for this estimate is proposed and includes four steps: a) joint analysis of regional trial data using a generalized linear model to obtain adjusted genotype means and covariance matrix of these means for the whole studied period; b) calculation of the arithmetic mean of the adjusted genotype means, exclusively for the group of genotypes evaluated each year; c) direct year comparison of the arithmetic means calculated, and d) estimation of mean genetic gain by regression. Using the generalized least squares method, a weighted estimate of mean genetic gain during the period is calculated. This method permits a better cancellation of genotype x year and genotype x trial/year interactions, thus resulting in more precise estimates. This method can be applied to unbalanced data, allowing the estimation of genetic gain in series of multilocational trials.