A análise de fatores na predição de ganhos por seleção em milho (Zea mays L.).

Analysis of prediction factors in yields by maize selection (Zea mays L.). The history and use of the Factor Analysis in agronomic studies, especially for the prediction of selection yields, is presented. The Factor Analysis was applied on data provided by the evaluation of 166 half-sib families of popcorn at the National Research Center in Maize and Sorghum, Sete Lagoas MG Brazil, in 1997-1998. Selection yield prediction based on scores from the Fator Analysis favored yields in the most important traits. Scores were used for yield prediction by direct and indirect selection and by several selection indices. The Factor Analysis is a useful multivariate method for prediction of selection yields and may either substitute the traditional method or supplement selection by selection indices

Associação entre características da parte aérea e do sistema radicular em mudas de guaranazeiro por correlações canônicas.

Este trabalho teve como objetivo quantificar o grau de asociação entre variáveis de parte aérea e de raízes em mudas clonadas de guaranazeiro, utilizando-se correlações canônicas, a fim de aperfeiçoar o procedimento de seleção de mudas para garantir o aumento da porcentagem de sobrevivência das mudas após o plantio

Influence of antiobiotics on NAA- induced somatic embryogenesis in eggplant (Solanum melongena L. cv. Embu).

The influence of increasing concentrations of naphthaleneacetic acid and the antibiotics cefotaxim?, timentin, kanamycin, and hygromycin on eggplant (Solanum melongena L. cv. Emb£) somatic embryogenesis was investigated. Cotyledon explants were excised from 16 to 20 days old in vitro grown seedlings. NAA promoted somatic embryogenesis, although its concentrations had no influence on the mean number of embryos. Callusing decreased significantly with increasing NAA concenti-ations. Morphogenesis was stopped with 50 to 100 mg L-I kanamycin and 7.5 to 15 mg L-I hygromycin. Although early globular embryos were observed up to 15 mg L-I, further embryo development was inhibited at 10 mg L .1. Interestingly, cefotaxime (250 and 500 mg L -1) promoted a marked effect on enhancing fresh weight of calli, accompanied by decrease in embryo regeneration, whereas timentin concentrations (150 and 300 mg L-I) did not affect embryo differentiation as compared to the control treatment

Interação genótipos x ambiente e estimativas de adaptabilidade e estabilidade de produção em clones de café Conilon.

Os objetivos deste trabalho foram estudar a ?performance?, a interação genótipos x ambientes e efetuar a análise de adaptabilidade e estabilidade de produção de 40 genótipos de café Conilon do Programa de Melhoramento Genético do INCAPER, em dois locais do estado do Espírito Santo em sete colheitas. Para estimação da adaptabilidade e estabilidade foi utilizada a metodologia de Cruz et al. (1989). Verificou-se que as condições edafoclimáticas de Sooretama e Marilândia são favoráveis para obtenção de ganho em produtividade, com o uso dos genótipos do Programa de Melhoramento Café Conilon do Incaper e, que os resultados são importantes para a seleção de clones para adaptação geral, para adaptações em ambientes favoráveis, ambientes desfavoráveis do Estado, para formações de variedades melhoradas e de populações base

Evaluation of Broiler Breeder Housing in High Temperature Brazilian Conditions

An experiment was conducted to investigate the effects of different cooling systems on bird thermal comfort, litter moisture content and the performance of broiler breeders, housed in open facilities at high temperatures conditions in Brazil. The study used Hubber lineage birds, from 26 to 37 weeks of age, in summer and fall conditions, in the Minas Gerais State, Brazil. Two facilities were used, with similar dimensions and construction characteristics, oriented in an east-west direction. Six replicates of six different systems of environmental control were evaluated: (fan jet with polytube and evaporative cellulose pad material, FJS; roof sprinkling (exterior), RSS; internal fogging system, IFS; two horizontal mixing fans directing air into the room, MFS; two roof-top wind-driven turbine ventilators, RVS; and a conventional system as the control, CTL, with ventilation provided solely by wind and no additional cooling. Hatchability, AH, was measured weekly. Results demonstrated that the FJS, IFS and MFS systems, in this sequence, performed best, presenting reduced BGHTI values and improved AH as compared to the other systems. Results obtained from the RVS and the CTL systems were markedly inferior. Litter moisture content (MC) was least in the MFS system while greatest in the FJS system