Implications of the number of years assessment on recommendation of common bean cultivars

In the common bean crop in Brazil, the requirement of the value for cultivation and use trials is that these experiments must be conducted over two years in three locations per region. Information in regard to the necessary number of years to ensure precision in cultivar recommendation and the influence of evaluated years in the estimation of the GE interaction are still scarce. Using grain yield of five check varieties assessed over 11 years in three sowing seasons per year, the aims of this study are as follows: to measure the relative contribution of the GE interaction, evaluating the implication of the number of years in the estimates of the GE interaction, and infer how many years are needed to ensure precision in cultivar recommendation. For instances, analysis of variance was carried out involving all environments and also combinations of years. The results showed that the GE interaction was greater than all other cross‐effects involving lines. The use of at least two years allows good coincidence in cultivar recommendation compared to the whole period. Increasing the evaluation time is a good strategy, especially when it is difficult to grow three different sowing seasons.     

Transformation of organoarsenical species by the microflora of freshwater crayfish

A study of the transformation of arsenic species by the microflora of the freshwater crayfish Procambarus clarkii was carried out. The study of the degradation of AB (arsenobetaine) was performed in aerobic conditions in two culture media (tryptic soy broth and saline medium) at two temperatures (30 and 8 degrees C). The microflora transformed AB into TMAO (trimethylarsine oxide), DMA (dimethylarsinate), MA (methylarsonate), and an unidentified compound (U1). The quickest transformations were carried out by microflora from hepatopancreas incubated in saline medium at 30 degrees C. The individualized study of other arsenic species [AC (arsenocholine), TETRA (tetramethylarsonium ion), TMAO, DMA, and MA] was also performed in saline medium. The only transformation observed was of AC into AB. The bacteria possibly responsible for AB degradation were isolated, identified by phenotypic and genotypic methods, and individually assayed for AB transformation. Only isolates allocated to the species Pseudomonas putida were able to metabolize AB.     

Yeasts used as fining treatment to correct browning in white wines

White wine was subjected to several fining treatments using baker's yeast at concentrations of 0.5, 1, 2, 3, 4, and 5 g/L. At all these concentration levels, the yeasts decreased the color of the wine in different degrees. The wine samples treated with the higher yeast concentration were subjected to analysis of phenolic compounds by HPLC and found to exhibit significantly decreased contents of vanillic, syringic and c-coutaric acids, and procyanidins B2 and B4, and colored compounds eluted at high retention times. The efficiency of the yeast-based fining treatment (1 g/L) was compared with traditional treatments such as those involving the use of activated charcoal or PVPP, which were employed at the usual concentrations in Sherry winemaking. This yeast treatment was found to provide results similar to those of the activated charcoal treatment in terms of A(420). Likewise, significant differences in the degree of retention of various phenols were observed among the three treatments compared. Finally, the wine samples obtained with the different treatments were subjected to a sensory panel. All the wines were found to exhibit improved color, aroma, and flavor with respect to the untreated samples, although the treatment using yeast at 1 g/L provided the best results in terms of aroma.     

Off-vine grape drying effect on volatile compounds and aromatic series in must from Pedro Ximénez grape variety

Changes in 36 volatile compounds of must from ripe grapes dried by direct exposure to sun and must from ripe grapes were studied. Compounds not dependent on sampling site in both musts were selected, and their concentration/Brix degree ratio values, were subjected to variance analysis. Only butan-1-ol and isoamyl alcohols showed no differences, while (E)-hex-3-en-1-ol, (Z)-hex-3-en-1-ol, (E)-hex-2-en-1-ol, (E)-hex-2-enal, hexanoic acid, isobutanol, benzyl alcohol, 2-phenylethanol, gamma-butyrolactone, gamma-hexalactone, and 5-methylfurfural, showed significant differences between the two must types, which may be ascribed to the drying process. An approach to describe must odor has been carried out by grouping volatile compounds in aromatic series, increasing their values in the fruity, solvent, sweet, and roasted series and diminishing the herbaceous as a consequence of the drying process.     

A comparison between the spatial distribution pattern of flagellates and some physicochemical parameters in a waste stabilization pond

Protozoological and physicochemical analyses were performed in a waste stabilization pond at Sto. Tomas Atzingo, a small town near Mexico City, in order to discern the internal dynamics of the pond water through the study of the spatial distribution pattern of flagellates and the parallel water volume distribution pattern of some selected physicochemical determined parameters. The statistical method applied to the data obtained was by cluster analysis. The results showed a slight trend to heterogeneity in the system, when it was evaluated through the physicochemically determined parameters. On the other hand, the spatial distribution pattern of the flagellates pointed out a remarkable heterogeneity in the pond. In systems like the one studied where the main feature is an organic matter overload, such a difference in findings indicates a low correlation between the biological parameters, in this case the flagellates, and the physicochemical variables, that should be considered when evaluating the water quality of such systems, either through the physicochemical, the biological or both scopes.     

Volatile compounds in Hispánico cheese manufactured using a mesophilic starter,a thermophilic starter,and bacteriocin-producing Lactococcus lactis subsp. lactis INIA 415

The effect of the addition of Lactococcus lactis subsp. lactis INIA 415, a strain harboring the structural genes of nisin Z and lacticin 481, on the formation of volatile compounds in Hispánico cheese manufactured with a mesophilic starter or with the mesophilic starter and a thermophilic starter was investigated. Addition of bacteriocin-producing L. lactis subsp. lactis INIA 415 to milk enhanced the formation of 2-methyl-propanal, 2-methylbutanal, 3-methylbutanal, 2-methyl-1-propanol, 3-methyl-1-butanol, 1-octanol, 2-butanone, and 2,3-butanedione. On the other hand, addition of thermophilic starter enhanced the formation of acetaldehyde, ethanol, 3-methyl-2-buten-1-ol, ethyl butanoate, ethyl hexanoate, 2-butanone, and 2,3-butanedione in Hispánico cheese. Stepwise discriminant analysis using the relative abundances of volatile compounds classified cheeses by type of starter, with function 1 related to thermophilic starter and function 2 to bacteriocin producer.     

Field compaction at different soil-water status: effects on pore size distribution and soil water characteristics of a Rhodic Ferralsol in Western Cuba

The level of compaction induced on cultivated fields through trafficking is strongly influenced by the prevailing soil-water status and, depending on the attendant soil degradation, vital soil hydraulic processes could be affected. Therefore, understanding the relationship between field soil-water status and the corresponding level of induced compaction for a given load is considered an imperative step toward a better control of the occurrence of traffic-induced field soil compaction. Pore size distribution, a fundamental and highly degradable soil property, was measured in a Rhodic Ferralsol, the most productive and extensively distributed soil in Western Cuba, to study the effects of three levels of soil compaction on soil water characteristic parameters. Soil bulk density and cone penetration index were used to measure compaction levels established by seven passes of a 10 Mg tractor at three soil-water statuses corresponding to the plastic (Fs), friable (Fc) and relatively dry soil (Ds) consistency states. Pore size distribution calculated from soil water characteristic curves was classified into three pore size categories on the basis of their hydraulic functioning: >50 μm (f_>50 μm), 50–0.5 μm (f_{50–0.5 μm}) and <0.5 μm (f_<0.5 μm). The greatest compaction levels were attained in the Fs and Fc soil water treatments, and a significant contribution to compaction was attributed to the existing soil water states under which the soil compaction was accomplished. Average cone index (CI) values in the range of 2.93–3.70 MPa reflected the accumulation of f_<0.5 μm pores, and incurred severe reductions in the volume of f_>50 μm pores in the Fs and Fc treatments, while an average CI value of 1.69 MPa indicated increments in the volume of f_{50–0.5 μm} in the Ds treatment. Despite the differential effects of soil compaction on the distribution of the different pore size categories, soil total porosity (f_Total) was not effective in reflecting treatment effects. Soil water desorption at the soil water potentials evaluated (0.0 to −15,000 cm H₂O) was adversely affected in the f_<0.5 μm dominated treatments; strong soil water retention was observed with the predominance of f_<0.5 μm, as was confirmed by the high water content at plant wilting point. Based on these findings, the use of field capacity water content as the upper limit of plant available soil water was therefore considered inappropriate for compacted soils.     

Degradation, under non-oxygen-mediated autooxidation, of carotenoid profile present in paprika oleoresins with lipid substrates of different fatty acid composition

A heat-induced degradation was carried out over two crude paprika oleoresins diluted with high oleic or high linoleic oil. Occurrence of oxygen was avoided, and changes in individual carotenoids were followed over time. Degradation rate constants were not significantly different, so that carotenoid stability was not linked with unsaturation degree of the oily system. A parallel reaction to degradation, trans to cis carotenoid isomer conversion, was also denoted during the thermal treatment, and it initially showed a higher rate than degradation of cis-isomers. Both processes (isomerization and cis-isomers degradation) were finally compensated, and their development was also unaffected by the nature of the lipid profile. Under the reaction conditions, oleic and linoleic fatty acids showed the same reactivity and induced degradative reactions, equally affecting the carotenoid profile. An enhanced stability of carotenoid content and provitamin A value was not achieved with a decrease in the unsaturation level of the oily system.     

Nitrogen dynamics during ecosystem development in tropical forest restoration

We considered whether ecological restoration using high diversity of native tree species serves to restore nitrogen dynamics in the Brazilian Atlantic Forest. We measured δ¹⁵N and N content in green foliage and soil; vegetation N:P ratio; and soil N mineralization in a preserved natural forest and restored forests of ages 21 and 52 years. Green foliage δ¹⁵N values, N content, N:P ratio, inorganic N and net mineralization and nitrification rates were all higher, the older the forest. Our findings indicate that the recuperation of N cycling has not been achieved yet in the restored forests even after 52 years, but show that they are following a trajectory of development that is characterized by their N cycling intensity becoming similar to a natural mature forest of the same original forest formation. This study demonstrated that some young restored forests are more limited by N compared to mature natural forests. We document that the recuperation of N cycling in tropical forests can be achieved through ecological restoration actions.