Clonal selection within the apricot varieties Trevatt and Moorpark

Barossa Valley selections of 5 Trevatt and 4 Moorpark apricot varieties were compared over 3 seasons for their characteristics as drying apricots.Although there was a lack of significant differences between Trevatt clones, enough differences occurred in the Moorpark varieties to suggest that many quality attributes, particularly fruit weight, diameter, pH, and drying ratio, can be improved through rigorous selection from a wide and diverse population. The data suggest that different clones may be better suited to particular sites or management systems. A large experimental error was noted and attributed to the variability in seedling rootstock material and the unknown viral status of the scions and rootstocks.

Peanut Breeding for Leafspot Resistance in Wide and Narrow Intrarow Spacings1

Sixteen peanut (Arachis hypogaea L.) genotypes were grown without the use of fungicides for two years in two planting arrangements, one an intrarow spacing typically used in commercial production (5 cm between plants) and the other typically used in breeding selection plots (30 cm between plants). At 10-day intervals throughout each growing season the proportion of necrotic leaf area caused by leafspots (Cercospora arachidicola Hori and Cercosporidium personatum (Berk. & Curt.) Deighton), leafspot disease rating (0-9), and stage of vegetative growth (v stage) were assessed. Leafspot disease ratings of genotypes spaced 30-cm apart were significantly correlated with the ratings of genotypes in 5-cm spacing. There was no interaction between genotypes and spacing. Percentage necrotic area in 30-cm and 5-cm plantings was significantly correlated. However, large experimental error and complex interactions among spacings, genotypes, and time of observation lessened the value of this method of disease assessment. While the correlation of v stage in the two spacings was highly significant, differences among genotypes were not consistent.

Determination of initial velocities of enzymic reactions from progress curves

The present communication describes a novel method for estimating initial velocities (v) of enzyme-catalysed reactions. It is based on an approximation of experimental data obtained by the cubic spline function. The initial velocity of a reaction is calculated as a derivative of the approximating function at a time value equal to zero. The proposed method is usable on a computer with a FORTRAN IV program. The method can be successfully used in such cases as substantial extents of substrate conversion, the inactivation of an enzyme in the course of a reaction, the existence of large experimental error or when the reaction mechanism is unknown.

Drying Spanish Peanut Pods with Short Duration, High Temperature Air Cycled Daily1

Freshly harvested Spanish peanut pods were dried with three different treatments in a controlled temperature and humidity environment. Each treatment included a different combination of temperature above 35°C and time held above this temperature. This procedure, or cycle of time and temperature, was repeated every 24 hours until a wet basis moisture content of approximately 10% was reached. A statistical analysis was conducted to determine whether or not there was any significant difference between treatments. At the 0.1 level of significance, statistical difference between treatments could not be shown. However, on the average, high temperature drying affected the percentage splits more than rate of drying. Splits also seemed to be affected more by temperature level than by exposure length. Findings relating to peanut quality are subject to large experimental error due to variations in variety, climatic and soil conditions, and maturity. Comparison of percentage sound splits was more meaningful when corrected for grade.

Investigation of Excited States of Helium Atoms in a Stationary PIG-Discharge

Spectral line intensities emitted by a quiescent PIG-discharge have been measured and the population densities up to a principal quantum number n = 24 have been derived from them. The experimentally determined population densities have been compared with theoretical ones calculated on the basis of a collisional-radiative model in which one accounts for electron and atom collisions. I t is shown that even in the case of different electron and atom temperatures, Te and Ta, an evaluation of the Boltzmann plot at medium and moderately high quantum numbers always leads to the electron temperature, whereas the Saha-Eggert equation for the same states may yield incorrect electron densities. The theoretical calculations predict an inflection of the slope of the Boltzmann plot from Te to Ta for very highly excited states. For the plasma para­ meters under which the PIG-discharge was operated (ne ≅ 2.5 × 1012 cm-3, Te ≅ 1200°K, n0 ≅ 1.5 × 1015 cm-3, 300°K) the change of the slope should become visible for states having principal quantum numbers n > 18. Due to the large experimental error bars it was not possible to check this behaviour.

STUDIES ON HOMOGENEOUS FIRST ORDER GAS REACTIONS: VI. THE DECOMPOSITION OF METHYLENE DIACETATE, METHYLENE DIPROPIONATE, AND METHYLENE DIBUTYRATE

The homogeneous decomposition of methylene diacetate vapor to formaldehyde and acetic anhydride at temperatures between 220° and 305 °C. and at pressures ranging from several centimetres of mercury to several atmospheres has been studied. Reaction rates were determined by analytical and by pressure change methods. The first order decomposition is opposed by a second order recombination. A secondary reaction makes it impossible to determine the exact position of the resulting equilibrium. Within the rather large experimental error, methylene diacetate has the same activation energy (33,000 cal.) as its homologues. Its specific reaction velocity is smaller than that of the ethylidene esters. Methylene dipropionate and dibutyrate decompose at the same rate as the diacetate. These facts are in accord with the hypothesis that the extent to which a radical can contribute to the energy of activation is dependent upon its position in the molecule. Veolcity constants are given by the equation [Formula: see text]