Hélio Wilson Lemos de Carvalho

Adaptabilidade e estabilidade de cultivares de milho no nordeste brasileiro

Forty six maize cultivars were evaluated during two years in 11 different places of Brazilian Northeast Region. Trials were carried out during the biennium 2001/2002 using experimental randomized block design, three repetitions, in order to know the adaptability and stability for cultivars recommendation. It was verified that the cultivars showed differentiated behavior among themselves in the mean of environments. The magnitude of the variance for local x cultivars interaction was more expressive than cultivars x years interaction, which suggests that the evaluations have to be done in a larger number of environments. Evaluated cultivars differed in adaptability and stability, and are very important for Brazilian Northeast Region.

Adaptabilidade e estabilidade produtiva de genótipos de feijão-caupi de porte semi-ereto na Região Nordeste do Brasil

O objetivo deste trabalho foi avaliar a adaptabilidade e a estabilidade da produtividade de graos de 20 genotipos de feijao-caupi de porte semi-ereto, utilizando o modelo de efeitos aditivos principais e interacao multiplicativa. Os ensaios foram conduzidos em 16 ambientes da Regiao Nordeste do Brasil. Os efeitos de genotipos, ambientes e da interacao genotipo x ambiente, e os tres primeiros eixos da analise de componentes principais (ACP) foram significativos. Os dois primeiros eixos da ACP explicaram juntos 55,11% da soma de quadrados da interacao, correspondendo a 83,20% do padrao da interacao genotipo x ambiente. As linhagens TE-97-321G-4, EVX-92-49E e EVX-63-10E apresentaram alta adaptabilidade, mas somente a ultima foi altamente previsivel. A cultivar BRS Guariba e as linhagens EVX-92-49E e TE97-321G-4 expressam melhor potencial genetico em ambientes de alta produtividade.

Inbreeding depression of 28 maize elite open pollinated varieties

The study of inbreeding depression is important for breeding strategies such as use of inbred progenies or extraction of inbreed lines. A diallel of 28 maize open-pollinated varieties was evaluated in 10 environments in the early 1990s. At the same time, S1 populations for each of the 28 varieties were evaluated in the same 10 experiments (environments). Yield reductions of the populations from S0 to S1 (mean of the 10 environments), varied from 34.6% (CMS-01) to 59.2% (CMS-30), with an average of 49.1%. Inbreeding depression was greater in populations with a wider genetic base, which had never been exposed to inbreeding (CMS-30, BR-107, PH4, Cunha, Saracura, Nitrodent, and Nitroflint). Inbred lines with greater yield means should be obtained from the BR-105, BR-111, CMS-01, CMS-03, BR-106, CMS-14c, and CMS-28 populations. The use of parameter estimates generated by analysis of inbreeding depression, allow to make inferences about frequencies of deleterious alleles in the population. The frequencies of favorable alleles in the parents can be obtained by diallel analysis. The association of these two types of information, can provide a better interpretation of the genetic parameters and also can improve the process of selection of parents for either an intra- or an inter-populational breeding program.

Heterotic responses of tropical elite maize accessions from Latin America with Brazilian testers

Little emphasis has been placed on identifying new sources of tropical maize germplasm that can be used in breeding programs. Additional information on the performance and heterotic classification of tropical germplasm is needed. This study was conducted to identify elite maize accessions from Latin America that could contribute to increase the level of heterosis with the best heterotic patterns of Brazil. Seventy-two elite accessions from the Latin American Maize Project (LAMP) were crossed with the testers BR 105 (flint kernel Suwan background) and BR 106 (dent kernel Tuxpeno background). The 72 crosses plus 9 checks were evaluated using a simple 9 ´ 9 lattice in four locations that represent one tropical region. The combined analysis showed highly significant differences among treatments for ear weight and the interaction treatment ´ location was also significant. With both testers better crosses for ear weight were identified in relation to the double cross BR 201 (commercial check). With the tester BR 105, the high parent heterosis ranged from ¾28% to 26%, the accessions SE 032 and PE 001 were selected for further work. With the tester BR 106, the high parent heterosis ranged from ¾35% to 17% and the accessions PE 011 and Pasco 14 were selected for further work. The selected accessions will be improved through recurrent selection schemes to increase yield and improve agronomic traits. Afterwards they can be exploited, within and between heterotic groups, to produce highly productive hybrid combinations, or used per se as improved maize varieties.

Adaptabilidade e estabilidade de produção de cultivares de milho no nordeste brasileiro

Twenty five cultivars of maize (Zea mays L.) were evaluated in 1994, in twelve different environments of the Northeast Region of Brazil. The trials were arranged in randomized block designs with three replications aiming to obtain knowledge concerning to the adaptability and yield stability of the cultivars in each environment. The significant effects related to environment, cultivars and cultivars x environments interaction gave the evidence of outstanding differences among that parameters. The hybrids showed better performance than the varieties, yielding in average 22.5% higher in relation to the environmental variations. Only the Cargill 505 and AG 510 hybrids showed poor adaptability in unfavorable environments. Taking in account the means presented by the varieties, CMS 39 was the most adjusted to the optimal genotype proposed in the model. None of the materials studied gave a determination coefficient (R2) lower than 80%, indicating a good production stability.

Estimativas de parâmetros genéticos na população de milho CPATC-3 em dois locais de Sergipe

From 1999 to 2001, the maize population CPATC-3 was submitted to three selection cycles among and within half sib families in two sites of Sergipe State in order to obtain genetic parameters estimates and to verify the behavior of the genetic variability for ear weight. In each selection cycle, 196 half sib families were evaluated in a completely randomized block design with two replications per local and the recombination of the best families within the same agricultural year was made. The results showed highly significant differences among the families from the base population and for all selection cycles, evidencing the genetic variability presence for ear weight. The genetic parameters estimates showed that the maize population CPATC-3 presents genetic variability for increasing ear weight and offers good perspectives to continue the breeding program.

Common bean cultivar BRS Ametista with large Carioca grains and disease resistance

BRS Ametista is a common bean cultivar with Carioca grain and yields similar to cultivar Perola, but with larger grain size, resistance to anthracnose and Fusarium wilt. It is recommended for 18 states in all regions of Brazil and can be planted on over 95% of the area used for common bean in the country.

Adaptabilidade e estabilidade de comportamento de cultivares de milho em treze ambientes nos tabuleiros costeiros do nordeste brasileiro

The potential of the Brazilian Northeast coastal tablelands for corn production and the adaptability and stability of sixteen corn cultivars were evaluated at thirteen environments of this region in 1994/95 on a randomized block design experiment with three replications. The large potential of this coastal strip for corn production was evidenced by the obtained yield, highlighting the hybrids, on the coastal tablelands of Piaui, Sergipe and Bahia States, where corn would become a major crop option for the growers. Pooled variance analysis showed significant difference for environments and cultivars, and the interactions environment x cultivar, which were inconsistent. Hybrids had better adaptation than varieties and populations; they are recommended for higher input situations. The AG 510 hybrid showed good adaptation to low and high input conditions, and therefore is recommended for both situations. The BR 5011, BR 5028, BR 106 and BR 5033 varieties had reasonable yields and are suitable for small and medium corn growers.

BRS Esteio: common bean cultivar with black grain, high yield potential and moderate resistance to anthracnose

BRS Esteio is a common bean cultivar with black grains of excellent cooking quality, suited for cultivation in 21 Brazilian States. In 77 trials of Value for Cultivation and Use, the cultivar had a normal cycle (90 days), an average yield of 2,529 kg ha-1, which is 8.1% higher than that of the control cultivars, a high yield potential (4,702 kg ha-1), upright growth, tolerance to lodging, and moderate resistance to anthracnose.

COMPORTAMENTO DE HÍBRIDOS DE MILHO SELECIONADOS E NÃO SELECIONADOS PARA ASI SOB ESTRESSE DE ÁGUA NO FLORESCIMENTO E NO ENCHIMENTO DE GRÃOS

Com o objetivo de verificar se a posicao da semente na espiga afeta diferentemente a produtividade e outros caracteres da planta e se essa diferenca pode ser ampliada por meio de ciclos seletivos, foi conduzido o presente trabalho. Para isto, na safra 1995/1996, foram semeadas, em lote isolado, cerca de 3.000 plantas da populacao CMS-39 e, por ocasiao da colheita, tomadas 300 espigas ao acaso. De cada espiga, foram coletadas sementes das extremidades e, posteriormente, as sementes da ponta de cada espiga foram misturadas e o mesmo foi realizado com as sementes da base. Esse procedimento foi repetido de modo analogo por cinco ciclos seletivos. As dez subpopulacoes, cinco da ponta e cinco da base, foram avaliadas em experimentos conduzidos nas safras 2000/2001 e 2001/2002. O delineamento utilizado foi o de blocos casualizados, com seis repeticoes, segundo esquema de parcelas subdivididas. Os tratamentos nas parcelas foram os cinco ciclos seletivos e, nas subparcelas, a origem das sementes, ponta ou base. Foram considerados os caracteres numero de dias para o florescimento masculino e feminino, altura de espiga e produtividade de graos. Constatou-se que a origem da semente da ponta ou da base nao alterou a expressao de varios caracteres avaliados e nao foi possivel, com a precisao experimental obtida, detectar efeito da selecao indireta para o vigor de polen pela posicao dos graos na espiga, em todos os caracteres considerados.