Antioxidant capacities,phenolic compounds,carotenoids, and vitamin C contents of nectarine,peach, and plum cultivars from California

Genotypic variation in composition and antioxidant activity was evaluated using 25 cultivars, 5 each of white-flesh nectarines, yellow-flesh nectarines, white-flesh peaches, yellow-flesh peaches, and plums, at the ripe (ready-to-eat) stage. The ranges of total ascorbic acid (vitamin C) (in mg/100 g of fresh weight) were 5-14 (white-flesh nectarines), 6-8 (yellow-flesh nectarines), 6-9 (white-flesh peaches), 4-13 (yellow-flesh peaches), and 3-10 (plums). Total carotenoids concentrations (in microg/100 g of fresh weight) were 7-14 (white-flesh nectarines), 80-186 (yellow-flesh nectarines), 7-20 (white-flesh peaches), 71-210 (yellow-flesh peaches), and 70-260 (plums). Total phenolics (in mg/100 g of fresh weight) were 14-102 (white-flesh nectarines), 18-54 (yellow-flesh nectarines), 28-111 (white-flesh peaches), 21-61 (yellow-flesh peaches), and 42-109 (plums). The contributions of phenolic compounds to antioxidant activity were much greater than those of vitamin C and carotenoids. There was a strong correlation (0.93-0.96) between total phenolics and antioxidant activity of nectarines, peaches, and plums.     

Efficiency of water use of early plantings of sunflower

Rain fed crop production in Mediterranean environments depends to a large extent on strategies that avoid the intense summer drought. Early plantings of sunflower have given consistently higher yields in such environments, but the basis for such yield increases has not been explored. We conducted two field experiments at Cordoba (Spain) to investigate the effects of an early and a late planting date on the components of water-limited crop productivity; namely, water use (T), water use efficiency (TE) and harvest index (HI) of sunflower. The results were generalized by simulating rain fed sunflower yields, under early (1 January) and late (15 March) plantings, for a 25-year period with the aid of a simulation model of the Ceres type (OILCROP-SUN) which has been validated in Cordoba. Experimental seed yields of early plantings in 1989 and 1996 were 2.0 and 3.0 t ha⁻¹, while late plantings yields were 1.3 and 2.4 t ha⁻¹, for the 2 years. Average simulated yields were 2.7 ± 1.1 and 1.9 ± 0.7 t ha⁻¹ for early and late plantings, respectively. For the 2 years, T of early plantings was higher than that of late plantings, but the response of TE and HI to planting date was not the same in the two experiments. In the simulation exercise, T and TE of early plantings were consistently higher than those of late plantings, while there were no differences in the HI for the two planting dates. We conclude that early plantings of sunflower increase rain fed yields by increasing both T and TE, while the impact of planting date on HI very much depends on the crop water stress pattern, which is quite variable from year to year even in the predictable Mediterranean environment.     

Butterfly biodiversity in the city is driven by the interaction of the urban landscape and species traits: a call for contextualised management

Landscape Ecology - Urbanisation is an environmental filter for many species that leads to community homogenisation, with a few species inhabiting isolated patches (e.g. public and private gardens...     

History and selection imprinting on genetic relationships among bovine breeds analyzed trough five genes related with marbling

Many candidate genes have been suggested as responsible for marbling in beef cattle, for instance diacylglycerol O-acyltransferase 1, thyroglobulin, growth hormone, leptin and stearoyl CoA desaturase. The objective of the present work was to evaluate the polymorphisms of five SNPs of these candidate genes in 389 animals of 18 Bos Taurus and Bos indicus breeds. The obtained results were compared with ones previously obtained with STRs and loci related to milk production in these populations. Moreover we analyzed whether the phylogenies reconstructed using SNPs associated with marbling resulted in the known tree topology. The tree constructed with UPGMA, using genetic distance D_A, exhibit a topology partially consistent with the historical origin of breeds. The result observed in the Correspondence Analysis coincided with the topology of the UPGMA tree. This work allowed us to evaluate the five SNPs genetic diversity and to demonstrate that the grouping of the breeds may be the result of its history, selection process, or both at once.     

Water relations of pistachio (Pistacia vera L.) as affected by phenological stages and water regimes

Pistachio is a drought tolerant fruit tree that can be cultivated in rainfed and irrigated conditions. The water requirements of the tree, however, are considerable so in most of the commercial orchards deficit irrigation is a common practice. Regulated deficit irrigation in pistachio trees has been described in several works, which reported that the phenological stage of shell hardening, so called stage II, is the most drought tolerant. This paper proposes that such drought resistance is related to changes in water relations linked to the phenological stages, even in conditions of no water stress. In order to evaluate such changes, the daily pattern of stem water potential and gas exchange (net photosynthesis, P_n, and leaf conductance, g_s) was measured, determining also the pressure–volume curves, in three different phenological stages of mature pistachio trees (Pistacia vera cv Kerman on P. terebinthus L. rootstock.). The daily pattern of stem water potential and gas exchange were performed in three different irrigation treatments: control, regulated deficit irrigation and rainfed. The pressure–volume curves were made only in the control and rainfed treatments. Significant differences were found in the daily pattern of stem water potential in all the phenological stages considered, while only in the last one the net photosynthesis was affected by water stress. The daily pattern of gas exchange at the beginning of the season was not affected by the evaporative demand, with a constant value when radiation was not limiting. Moderate levels of water stress during the last measurement date reduced the maximum values of g_s and P_n resulting also in a clear change in the pattern of the daily curve, with maximum values only at the beginning of the day. The relationships between stem water potential and gas exchange parameters were different during stage II and almost the same in stages I and III. The parameters drawn from the pressure–volume curves also indicated a change in the elastic modulus of the leaf cells in stage II. In addition, differences in the osmotic adjustment (OA) index suggested different degree of osmotic adjustment of the phenological stages in the response to water stress. The results showed that different mechanisms of drought resistance are operating in the different phenological stages in pistachio trees.     

National assessment of the evolution of forest fragmentation in Mexico

This paper presents assessments of the fragmentation of the temperate and tropical forests in Mexico at the national level for two dates 1993 and 2002. The study was based on land use and vegetation cover data sets scale 1:250,000. Two broad forest types (Temperate Forests and Tropical Forests) and five more specific forest types (Broadleaf Forests, and Coniferous Forests; Tropical Dry Deciduous Forests, Tropical Sub-evergreen Forests, and Tropical Evergreen Forests) were defined to conduct the analyses. FragStats 3.3 was used to estimate nine metrics of the spatial pattern of the forests for each forest type and date considered. The results indicate that the land cover transitions that have occurred between 1993 and 2002 have resulted in more isolated forest patches with simpler shapes in both the Temperate and Tropical Forests. The remaining Tropical Forest patches have become smaller and more numerous. In contrast, the remaining Temperate Forest patches are fewer and on average larger. Of the more specific forest types defined in this study, the Broadleaf Forests have the highest indicators of fragmentation. However these forests are usually embedded or adjacent to Coniferous Forests. Of more concern for conservation purposes are the high values of fragmentation metrics found for the Tropical Evergreen Forests and Tropical Dry Deciduous Forests, because these forest types are usually surrounded by non-forest land covers or anthropogenic land uses.     

The economic feasibility of precision agriculture in Mato Grosso do Sul State,Brazil: a case study

The objective of this study was to carry out a comparative analysis of the costs and economic profitability and viability indicators involved in implementing precision and conventional farming practices using maize and soybean crops in the state of Mato Grosso do Sul, Brazil. After identifying the production costs, analyses of the profitability indicators and viability indicators were carried out. The calculated profitability indicators (gross revenue, gross margin, break-even point, operational profit, and profitability index) presented better economic results under the precision system. For the analysis of the viability indicators, the net present value method and the internal rate of return method were used to analyze the two production systems, showing smaller investment attractiveness for the conventional farming system than for the precision system, though with a small difference in values. The Monte Carlo method was applied to evaluate investment risk. The selection of the variables to be simulated was based on the sensitivity analysis results, such as production, sale price and input price. The results obtained through simulation led to the conclusion that the risks are low for the two production systems analyzed.