Heritability estimation in early generations of two-way crosses in soybean

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Suckling behaviour of Nelore, Gir and Caracu calves and their crosses

It is reasonable to assume that the knowledge of suckling behaviour contributes to optimal management and selection of beef cattle. However, there is little information about suckling behaviour of some beef cattle breeds. The aim of this study was to describe the suckling behaviour of two zebu (Bos indicus) and one criollo (Bos taurus) breeds, analysing the potential effects of breed and some environmental factors on suckling frequency and duration. Forty cows, 17 Nelore, 14 Gir (both zebu) and 9 Caracu (criollo) were bred in a diallelic crossing design. The cows and resulting calves were kept on pasture from birth to weaning. Their behaviour was recorded weekly during daylight. Three behavioural traits were considered: number of suckling meals (NSM), duration of each suckling meal (DSM) and total suckling duration (TSD). Allosuckling was not observed. The calves suckled at any time during the daylight and the overall means were: NSM = 2.57 +/- 0.05 meals/12 h (from back transformed data), DSM = 9.25 +/- 0.11 min/suckling meal and TSD = 23.76 +/- 0.47 min/12 h. There was an effect of dam's breed on NSM and DSM; the calf's genetic group within breed of cow influenced NSM and TSD when the dams were from the Nelore breed. The age of calf had significant effects on all traits. Males averaged higher NSM and TSD (2.60 +/- 0.03 meals and 25.05 +/- 1.37 min/12 h, respectively) than females (2.12 +/- 0.04 meals and 21.51 +/- 1.55 min/12 h, respectively). The differences in suckling behaviour seem to be produced by a complex combination of genetic and environmental factors, which result in a particular behavioural relationship within mother-offspring pairs. (c) 2006 Elsevier B.V. All rights reserved.

Candidate SNPs for carcass and meat traits in Nelore animals and in their crosses with Bos taurus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of single nucleotide polymorphisms of CAPN1 and CAST genes on meat traits in Nellore beef cattle (Bos indicus) and in their crosses with Bos taurus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Intraspecific crosses resulting in the first occurrence of eight and nine B chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Study of the length of the mouthparts of Africanized, Caucasian and Africanized/Caucasian honey bee crosses, and relationships between glossa sizeand food gathering behavior

Os comprimentos das peças que constituem o aparelho bucal, glossa, paraglossa, estipite, gálea, palpo labial, palpo maxilar, cardo, lorum, mento e pré-mento foram estudados a nível unidimensional em abelhas caucasianas, africanizadas e nos descendentes F1. Somente a paraglossa, estipite, gálea, palpo maxilar, mento e pré-mento mostraram ser diferentes entre esses 2 tipos de abelhas. Essas 6 variáveis foram estudadas nos descendentes F1, tendo sido utilizados 2 tipos de cruzamentos: rainhas caucasianas x machos africanizados (cruzamento 1) e rainhas africanizadas x machos caucasianos (cruzamento 2). Análises multidimensionais também foram realizadas, tendo sido obtidas as distâncias generalizadas de Mahalanobis (D2) entre os parentais e os descendentes F1. Tanto nas análises unidimensionais como nas multidimensionais houve aparente dominância das abelhas africanizadas, mas o número de genes não pôde ser conhecido porque só havia a geração F1 e não houve controle da heterozigosidade das 2 colônias parentais. Os cálculos dos coeficientes de correlações de Spearman mostraram que as abelhas com glossae mais longas coletaram mais xarope de açúcar e voaram mais lentamente da colônia para a fonte de alimento.

PRODUCTIVITY IN MASS CROSSES OF DROSOPHILA-STURTEVANTI - A COMPARATIVE-STUDY OF LABORATORY STOCKS AND RECENTLY COLLECTED FLIES

Drosophila sturtevanti from several geographic origins were analyzed for their capacity to intercross and to yield progeny. Mass intercrosses involving laboratory stocks and recently collected strains were fertile, which suggests that the genetic differentiation among these geographically isolated populations did not affect their reproductive patterns sufficiently to lead to reproductive isolation. Analysis of the number of progeny (productivity) in intracrosses and intercrosses was informative as to the amount of variation this feature exhibits in the laboratory stocks and in the recently collected strains. Also laboratory stocks and recently collected flies shared a positive correlation in that the greater the control productivity of a strain the greater the number of its intercrosses which exhibited reduced productivity.

Top crosses de linhagens S2 de milho shrunken-2 em função da endogamia do testador

Pós-graduação em Agronomia (Horticultura) - FCA

Cytogenetic and morphologic approaches of hybrids from experimental crosses between Triatoma lenti Sherlock & Serafim, 1967 and T. sherlocki Papa et al., 2002 (Hemiptera: Reduviidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

MELHORAMENTO do TRIGO: XXXI. HERDABILIDADES E CORRELAÇÕES ENTRE TRÊS CARACTERÍSTICAS AGRONÔMICAS em POPULAÇÕES HÍBRIDAS

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Características anatômicas e morfométricas do ligamento oblíquo do cotovelo de eqüinos

Neste trabalho, algumas características anatômicas e morfométricas do ligamento oblíquo do cotovelo do eqüino foram descritas em dez animais adultos, sem raça definida, que não apresentavam afecções dos órgãos locomotores. O ligamento oblíquo origina-se dorsal à fossa radial do úmero, atravessa obliquamente a superfície cranial do cotovelo e se divide em uma porção longa, que se insere na tuberosidade radial, e em outra curta, que se une à porção longa do ligamento colateral medial. Foram efetuadas medidas visando a obter o comprimento e a largura máximas entre a origem e a inserção do ligamento oblíquo, não sendo observadas diferenças (P>0,05) nas comparações feitas entre os sexos e os antímeros. O ligamento oblíquo contribui no efeito mola e na manutenção da estabilidade da articulação do cotovelo do eqüino. Pela particularidade de sua localização, cranial à articulação, o ligamento oblíquo possui ação frenadora, impedindo a extensão completa da referida articulação.

A quantitative nature of somatic embryogenesis in soybean

The objectives of this research were to investigate the genetic parameters associated with the in vitro formation of somatic embryos in soybean and to determine the effect of light intensity on the embryogenic capability of F-1, F-2, and backcross (RC1P1 and RC1P2) progenies derived from crosses between embryogenic (IAS-5 and Embrapa-1) and nonembryogenic (Parana) cultivars. Immature cotyledons (4-6 mm in length) derived from the parental lines, F-1, F-2, RC1P1, and RC1P2 were grown for 90 d on the inductive N10 medium, after which the number of somatic embryos was recorded. Chi-square tests for goodness of fit showed that the genetic component of the somatic embryogenesis trait is controlled in a quantitative manner by approximately 10 genes. A normal distribution for somatic embryo formation in the F-2 generations was observed reinforcing the quantitative nature of the trait. Variation in light intensity (8-12 and 27-33 mu mol m(-2) s(-1)) had no effect on somatic embryo formation in the parental material tested.

Genetics of resistance to powdery mildew (Microsphaera diffusa) in Brazilian soybean populations

Crosses between resistant and susceptible soybean cultivars were performed and the F2 populations were obtained to study the inheritance of soybean resistance to powdery mildew and to estimate the number and action of genes related to resistance. The reaction to powdery mildew was studied in a greenhouse and pots carrying plants with symptoms were distributed among the pots carrying the genotypes to be tested as a source of inoculum. Individual plants were scored according to the method of Yorinori (1997), with modifications, and classified as resistant or susceptible. The results showed that adult soybeans plants can present resistance to powdery mildew, which is controlled by one major gene with a dominant effect.

Validation of microsatellite markers for assisted selection of soybean genotypes resistant to powdery mildew

Powdery mildew is one of the most serious diseases of soybean and is found in all producing countries. The purpose of this study was to validate microsatellite markers previously identified as associated with resistance to powdery mildew in soybean. The study was conducted in two F, parent populations with contrasting resistance to powdery mildew, In the analysis 10 SSR primers were used for the populations. and tour polymorphic markers were identified for cross I (MGBR95-20937 x IAC-Foscarin 31) and three for cross 2 (MGBR-46 x Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) 48). The Chi-square analysis of the phenotypic evaluation confirmed the expected segregation (3: 1) of a dominant gene related to resistance. The polymorphic markers also segregated as expected (1:2:1). The markers Sat 366 and Sat 393 in the crosses 1 and 2. respectively, located at 9.41 and 12.45 cM from the gene. were considered promising for marker-assisted selection for resistance to powdery mildew in soybean. at a selection efficiency of 92.7% and 60.3% respectively.