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 Cultivar BRS A706 CL is a new rice cultivar, resistant to herbicides of the chemical group of imidazolinones, with a yield potential of 15,635 kg ha-1. It has intermediate maturation, lodging tolerance, the stay green trait, moderate rice blast resistance, a high milling yield and premium 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.

Abstract BRS A501 CL is the first upland rice cultivar with tolerance to the broad-spectrum herbicide Kifix®. It has a medium-length cycle, high stability of whole grain yield at processing, good disease tolerance and a high grain yield.

Abstract BRS 901 and BRS 902 are red pericarp rice cultivars developed by Embrapa for irrigated and rainfed lowland production systems in Brazil. These cultivars have medium and early maturation cycles, respectively, and both have high grain yield potential, good lodging tolerance and short to medium length grains.

Abstract BRS Catiana is an irrigated rice cultivar with a medium cycle and excellent grain quality, suited for cultivation in 17 Brazilian states. It has a high yield potential (15,535 kg ha-1) and a mean yield of 7,253 kg ha-1, wide adaptation and late senescence (stay green trait).

Abstract BRS Pampeira is a rice cultivar developed by Embrapa, recommended for irrigated cultivation in Brazil. It shows modern architecture, with high tillering and tolerance to lodging. It stands out for its high yield potential, medium cycle and good grain quality.

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.

O N é o nutriente de maior importância para a produtividade do arroz (Oryza sativa L.). Este trabalho teve por objetivo avaliar a resposta de cultivares de arroz de terras altas em função de diferentes doses e épocas de adubação nitrogenada. Utilizou-se o delineamento experimental em blocos casualizados com parcelas subsubdivididas, com quatro repetições. Foram estudadas cinco cultivares de arroz (BRS MG Curinga, BRS Monarca, BRS Pepita, BRS Primavera e BRS Sertaneja), três épocas de aplicação de N (100 % na semeadura; 50 % na semeadura e 50 % no perfilhamento; e 100 % no perfilhamento) e quatro doses de N (0, 50, 100 e 150 kg ha-1). As cultivares avaliadas responderam ao incremento de doses e à época de aplicação de N, destacando-se BRS Primavera e BRS Sertaneja como as mais produtivas quando as doses de N foram distribuídas 50 % na semeadura e 50 % no perfilhamento, enquanto a cultivar BRS Monarca apresentou a melhor resposta à adubação nitrogenada quando todo o N foi aplicado no perfilhamento.

Nitrogen is the most important nutrient for rice (Oryza sativa L) yields. This study aimed to evaluate the response of upland rice cultivars to N rate and application times in a randomized block design, in subdivided plots with four replications. The studied factors were five rice cultivars (BRS MG Curinga, BRS Monarca, BRS Pepita, BRS Primavera, and BRS Sertaneja), three application times (100 % at planting, 50 % at planting - 50 % at tillering and 100 % at tillering) and four N rates (0, 50, 100, and 150 kg ha-1). All cultivars responded to increased rates and different times of N application, especially BRS Primavera and BRS Sertaneja, which were the most productive when 50 % N rates were applied at sowing and 50 % at tillering. The response of cultivar BRS Monarca to N fertilization was best when 100 % of the fertilizer was applied at tillering.

O objetivo deste trabalho foi determinar o potencial produtivo e a interação entre genótipos e ambientes em 550 acessos da Coleção Nuclear de Arroz da Embrapa. O desempenho, a adaptação e a estabilidade produtiva de cada genótipo foram avaliados por meio da metodologia de análise dos efeitos principais aditivos e interações multiplicativas (AMMI), em nove experimentos de campo, realizados em seis Estados, em condição de sequeiro e irrigada, durante três anos agrícolas. Foi realizada a análise por meio de modelos lineares mistos, e as estimativas de componentes de variância foram obtidas pelo método de máxima verossimilhança residual (REML), com aplicação do procedimento de melhor predição linear não viesada (BLUP) para a predição dos valores genéticos dos efeitos aleatórios (EBLUP) associados a cada um dos acessos. O grupo de acessos com melhor desempenho foi o de linhagens e cultivares brasileiras (LCB), conforme o esperado. No entanto, foram identificadas variedades tradicionais (VT) entre os genótipos mais produtivos, o que mostra o potencial deste grupo de germoplasma em contribuir com novas fontes de variabilidade genética para programas de melhoramento. Foram identificados acessos superiores quanto à estabilidade, adaptabilidade e produtividade de grãos, entre os quais destacam-se CA880078, CA840182 e CNA00091.

The objective of this work was to determine the productive potential and the genotype by environment interaction of 550 accessions of the Embrapa's Rice Core Collection. The performance, and yield adaptability and stability of each genotype was evaluated using the additive main effects and multiplicative interactions (AMMI) approach, in nine field experiments, carried out in six Brazilian states, under dry and irrigated conditions, during three years. The linear mixed model analysis was performed, and the estimates of the variance components were obtained by the residual maximum likelihood (REML), using the best linear unbiased prediction (BLUP) procedure for the prediction of the genotypic values of random effects (EBLUP) associated with each accession. The group of accessions with better performance was the one of lines and cultivars from Brazil (LCB), as expected. However, traditional varieties (VT) were identified among the best yielding genotypes, which shows the potential of this germplasm group to contribute as a new source of genetic variability to breeding programs. Superior accessions were identified for their stability, adaptability and grain yield, among which CA880078, CA840182 and CNA00091 stand out.

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.

Objetivando avaliar os progressos obtidos pelo programa de melhoramento genético do arroz (Oryza sativa L.) irrigado, desenvolvido no meio-norte do Brasil, foram analisados os dados de produtividade de grãos, floração média, altura de planta e acamamento das linhagens componentes de 37 ensaios comparativos avançados, conduzidos de 1984 a 1997. Além das testemunhas (`Cica 8' e `Metica 1'), 89 linhagens foram contempladas neste estudo. Nesse período, o ganho médio anual de produtividade foi de apenas 0,3%, significativo (p < 0,05), porém de baixa magnitude. As correlações genéticas estimadas pelos métodos convencional e indireto foram de magnitudes semelhantes. Das seis cultivares recomendadas para cultivo no período avaliado, a Diamante proporcionou ganhos consideráveis quanto à qualidade dos grãos, em comparação com as testemunhas.

Data from 37 advanced yield trials, conducted from 1984 to 1997, were analyzed to evaluate the genetic progress made by the Brazilian Mid-north Region irrigated rice (Oryza sativa L.) breeding program. The following traits were measured: grain yield, days to flowering, plant height, and lodging. These trials had 89 breeding lines and two checks (`Cica 8' and `Metica 1'). During these 14 years of experiments, the annual gain for grain yield was small and equal to 0.3%, but statistically significant (P < 0.05). The genetic correlations estimated by the conventional and indirect methods were similar. Out of the six cultivars recommended for the region during this period, the cultivar Diamante provided significant gains for grain quality, when compared to the checks.