Cosme Damião Cruz

Repetibilidade de características do fruto de aceroleira

The objective of this paper was to estimate the repeatability coefficient (RC) of the fruit traits such as height (FH), diameter (FD), weight (FW), C vitamin (VitC), total soluble solids (TSS), pulp weight/fruit weight relation (PFR) and the titrable acidity (TA), while the number of measures that should be performed for an efficient selection of the genotypes under evaluation were determined. Analysis were made using the ANOVA, principal components and structural analysis methodology. The estimates of the RC for FH, FD, FW, VitC and TA demonstrated high regularity at the superiority of the individuals from one cycle to another, so the evaluation of two cycles was enough to predict the individuals real value with R2 above 90%. To TSS, in average, eight evaluation cycles were necessary to reach a R2 above 90%. PFR showed to be highly irregular, so the evaluation of at least 26 cycles turned to be necessary in order to reach a R2 above 90%. Such an irregularity was attributed to the method used in analyzing the characteristic, then the search for a more accurate and stable method was necessary.

Divergência genética em linhagens de pimentão em relação à eficiência nutricional de fósforo

Avaliaram-se 10 linhagens de pimentao (Capsicum annuum L.) quanto a eficiencia nutricional em relacao ao P, bem como a dose de P mais adequada para estudos geneticos, e o carater que mais contribuiu para a divergencia genetica. O experimento foi conduzido em casa de vegetacao, em solo, na Universidade Federal de Vicosa. Os tratamentos foram distribuidos em arranjo fatorial 10 x 5 x 4, constituidos de 10 linhagens, cinco doses de P (0, 250, 500, 750 e 1.000 mg de P/kg de solo) e quatro repeticoes, em delineamento de blocos casualizados. Em cada dose de P aplicada ao solo foi realizada uma analise multivariada. Constatou-se variabilidade genetica entre as linhagens estudadas em todas as doses de P adicionadas ao solo, sendo a dose 250 mg de P/kg de solo a que melhor discriminou as linhagens; portanto, a mais indicada para estudos geneticos. Com essa dosagem, constatou-se que a producao de materia seca da parte aerea foi o carater que mais contribuiu para a divergencia genetica entre as linhagens, podendo ser um parâmetro adequado para selecao em estudos geneticos.

Análise de trilha do rendimento do feijoeiro e seus componentes primários em monocultivo e em consórcio com a cultura do milho

Path analysis of grain yield (basic variable) and its primary components (explicatory variables) was worked in common bean in monoculture and intercropped with maize. In general, the results were similar in both cropping systems. Among the explicatory variables studied, only the number of pods per plot showed a good combination of path coefficient and correlation, both high, in monoculture and intercropped. It could be concluded that the character number of pods per plot has an important influence on grain yield, which may be of great value for genetic gains in this character, by indirect selection.

Considerações sobre duas metodologias de análise de estabilidade e adaptabilidade

Thirty one commercial maize hybrids were evaluated in the southern Mato Grosso State, Brazil, 16 being regular crop (1996/97) and 15 in the late of sowing (February ending and the beginnig of March, 1997) making possible analyses of stability and adaptability for each period. Each experiment was carried out in randomized block design with three repetitions. The metodologies of EBERHART & RUSSELL (1966) (univariate analysis), LIN & BINNS (1988) (univariate analysis) and modifications by CARNEIRO (1998) (univariate and multivariate analysis) were applied. Significant effects were verified for environment, hybrids, hybrids x environment interactions and combined deviations. The majority of the hybrids showed wide adaptability and good stability according to EBERHART & RUSSELL (1966) methodology. The methodology of b1iN & BINNS (1988) modified by CARNEIRO (1998) was more discriminant than EBERHART & RUSSELL (1966) and because of that, more efficient and suitable for analysis of stability and adaptability. The multivariate analysis allowed to understand better the performance of the genotypes being an important complemental tool in the genotype indication in agreement with their performance.

Alocação de fotoassimilados em folhas e frutos de cafeeiro cultivado em duas altitudes

The objective of this work was to evaluate the allocation of carbohydrates in fruits of Arabic coffee plant during the period comprised among the anthesis and maturation in two different altitudes, as well as, the variation in its content in leaves of these productive branches. The experiment was constituted of the coffee plant variety (Coffea arabica L.) Catuai IAC-44 cultivated at 720 and 950 m above the sea level in Martins Soares, Minas Gerais State, Brazil. The experimental design was completely randomized with three repetitions using split- plot in time scheme. The altitude of 720 m contributed to an acceleration in the accumulation of starch, total soluble sugar, reducing sugar and non-reducing sugar in coffee plant fruits. The accumulation of starch in the altitude of 720 m preceded the accumulation in the altitude of 950 m, presenting larger earning percentage in the fruit fast expansion stadium. In this stadium, carbohydrate concentrations in leaves in the 3 rd and 4 th leave pairs of productive branches decreased abruptly indicating that this is the most critic period for the carbohydrate concentrations in leaves. Altitude influenced the extension of the cycle, as well as the assimilate accumulation by fruits and that variation in coffee plant leaves.

Adaptabilidade e estabilidade via regressão não paramétrica em genótipos de café

The objective of this work was to evaluate a methodology of phenotypic adaptability and stability analyses of coffee genotypes based on nonparametric regression. The technique used differs from other techniques because it reduces the influence of extreme points resulting from the presence of genotypes whose answers to a certain environment are too different on the estimation of the adaptability parameter. Data from an experiment studying the average yield of 40 coffee (Coffea canephora) genotypes in a randomized block design with six replicates were used to evaluate the method. The genotypes were evaluated along five years (1996, 1998, 1999, 2000 and 2001) in two locations (Sooretama and Marilândia, ES, Brazil), in a total of ten environments. The methodology proposed proved adequate and efficient, since it eliminates the disproportionate effects induced by the presence of extreme points and avoids misleading recommendations of genotypes in terms of adaptability.

Seleção de genitores de Eucalyptus grandis e de Eucalyptus urophylla para produção de híbridos interespecíficos utilizando REML/BLUP e informação de divergência genética

RESUMO – Foram avaliadas 363 progenies de meios-irmaos de Eucalyptus urophylla e de 245 progenies de meios-irmaos de E. grandis, visando a selecao de genitores para a producao de hibridos interespecificos em cruzamentos controlados em dialelo circulante, com base em seus valores geneticos preditos. Os ensaios foram conduzidos em Guanhaes, MG, no delineamento de blocos casualizados com cinco repeticoes, parcelas lineares de seis plantas para E. urophylla e oito plantas para E. grandis, no espacamento de 3,0 x 2,0 m. Os parâmetros geneticos foram estimados adotando-se modelos mistos com uso do procedimento REML/BLUP (maxima verossimilhanca restrita/melhor predicao linear nao viesada) para diâmetro a altura do peito (DAP), altura total (ALT) e volume individual (VOL). A predicao dos valores geneticos foi feita somente para (DAP), caracteristica que foi utilizada para selecao. Em E. urophylla, foram obtidas as estimativas de herdabilidade no sentido restrito de 0,2785 e de acuracia da ordem de 61%, e em E. grandis, herdabilidade de 0,2247 e acuracia de 53%. A selecao dos 100 genitores de cada especie individualmente proporcionara ganhos geneticos na ordem de 20,6% em E. urophylla e de 16,4% em E. grandis. Ganho genetico para DAP em torno de 35,0% podera ser obtido com o cruzamento dos 10 individuos selecionados para cada especie, portadores das maiores estimativas de divergencia genetica.

Fatores que afetam a germinação do grão de pólen do maracujá: meios de cultura e tipos de agrotóxicos

Temperature, culture medium, incubation period and pH for yellow passion fruit (Passiflora edulis f. flavicarpa) pollen germination, as well the effect of agrotoxics were studied. Temperature of 28 ± 0.5°C, culture medium with 50 g/L of sacarose, 0.2 g/L of boric acid and 1.0 g/L of calcium nitrate showed better germination of P. edulis f. flavicarpa pollen. No effect of the incubation period (17 and 48 hours) was registered for pollen germination of this plant. Percentage of pollen germination of P. edulis f. flavicarpa was not affected by the acaricid Dicofol + Tetradifon and by the insecticides Cartap, Fenpropathrin, and Abamectin. There was a small reduction in pollen germination in the presence of insecticides Malathion, Fenthion, Thrichorfon, Vamidothion, Deltamethrin, Methyl Parathion and the spreader-sticker N-dodecil benzen sodium sulphate. Ethion and Lambdacyhalothrin had severe effect on pollen germination of this plant.

Inferências genéticas na produção e qualidade de tomateiro sob cruzamento dialélico

Genetic inferences on the performance of five tomato cultivars (Ângela I.5100, Floradade, IPA-05, Jumbo AG-592 and Santa Clara) and their p(p - 1)/2 hybrids for production characteristics and fruit quality were obtained through Haymans methodology (1954). The results showed a favorable situation for breeding to production characteristics, but not for content of soluble solids, total carotenoids, and content of betacarotene. The data evidenced low variability in the cultivars studied.

Abordagem bayesiana para avaliação da adaptabilidade e estabilidade de genótipos de alfafa

The objective of this work was to propose a Bayesian approach for the Eberhart & Russell method to evaluate the phenotypic adaptability and stability of alfafa (Medicago sativa) genotypes, as well as to evaluate the efficiency of the use of prior informative and noninformative distributions. Data from a randomized block design experiment evaluating the forage dry weight of 92 genotypes were used. The Bayesian methodology proposed was implemented in the free software R by the MCMCregress function of the MCMCpack package. To represent the noninformative prior distributions, a probability distribution with high variance was used; and, to represent the informative prior, a meta‑analysis concept was adopted, characterized by the use of information provided by previous studies. The comparison between the prior distributions was done using the Bayes Factor, with the BayesFactor function of the MCMCpack package, which indicated that an informative prior is more appropriate under the conditions of this study.