Suitability of Organic Potatoes for Industrial Processing: Effect of Agronomical Measures on Selected Quality Parameters at Harvest and after Storage

Three factorial field experiments were conducted in two consecutive years (2003 and 2004) on two sites in order to examine the impact of preceding crop, pre-sprouting, N and K fertilization and cultivar on quality attributes of organically grown potatoes destined for processing into French fries or crisps. Tuber dry matter (DM) concentration, glucose and fructose concentrations, as well as the colour of crisps and the quality score of French fries, were assessed at harvest and after a 4-month storage period. Results suggest that tubers from organic potato cropping may be expected to have sufficiently high tuber DM concentrations (>19%) for processing into French fries without impairing the texture of the fries when concentrations exceed 23%. DM concentrations of tubers for crips (cv. Marlen) fell short of the required minimum of 22% when a combined N and K fertilizer was applied. The tuber DM concentration was significantly lower following peas than following a legume-grass/clover ley or cereals (oats or winter wheat), but only in one of two seasons. Pre-sprouting increased tuber DM concentration considerably, especially in the growing season with a high incidence of Phytophthora infestans (+1.2% absolute increase). Tuber DM concentration was significantly higher after storage in two of three experiments (+0.4 and 0.5% absolute increase). Cultivars belonging to the very early and early maturity type showed the largest relative increase in reducing sugars concentrations due to storage, ranging between 300 and 1,100%. The medium-early cv. Agria and medium-late cv. Marena proved to be best suited for processing into French fries under conditions of organic farming, as only minor deviations from the highest quality standards were established at harvest (quality index at 4.3 and 4.1, respectively). A consistently high crisp quality was achieved by the medium-early cv. Marlen, with L-values of 70.8 and 66.7 at harvest and after storage, respectively. Overall, results show that the quality variables were mainly affected by cultivar, season, storage and their interaction. The effect of agronomical measures, such as fertilization, preceding crop and pre-sprouting of seed-tubers, was rather small and their effect on internal tuber quality and quality of fried products may hardly be predictable. The quality standards for tuber raw stock can be accomplished best when adequate cultivars are chosen.     

Correlation between Fusarium head blight severity and DON content in triticale as revealed by phenotypic and molecular data

Fusarium head blight (FHB) in triticale (× Triticosecale Wittmack) results in yield losses and mycotoxin contamination, for example, by deoxynivalenol (DON). This study aimed to analyse the correlation between FHB severity and DON content in a DH population of 146 entries across environments. Additionally, Fusarium damaged kernel (FDK) rating, heading stage and plant height were recorded. Highly significant (P < 0.001) genotypic variances were found throughout, but also significant (P < 0.001) genotype–environment interaction variances occurred. Correlation between FHB severity and heading stage or plant height was low (r = 0.144 and r = ?0.153, P < 0.10). A prediction of DON content from FHB severity or FDK rating is not possible caused by low correlations (r = 0.315 and 0.572, respectively, P < 0.001). A common quantitative trait locus (QTL) for all FHB‐related traits was found on wheat chromosome 2A being of minor importance for FHB severity, but of high importance for DON content and FDK rating. Another QTL on rye chromosome 5R was more important for FHB severity. In conclusion, DON content has to be measured in triticale after selection for FHB severity to gain for healthy and mycotoxin‐reduced feed.     

Wood characteristics of Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray native to Costa Rica: their significance for wood utilization

Due to over-exploitation in the past, native conifer species in many tropical countries are hardly available anymore for wood utilization. In the last decades Costa Rica has undertaken considerable efforts to study the silvicultural characteristics of the native species of the family Podocarpaceae, in particular Podocarpus oleifolius var. macrostachyus (Parl.) Buchholz and Gray, in order to evaluate its suitability for cultivation in mixed plantations with preference for native species. However, sufficient information on the structural, chemical and physical characteristics of the wood of this species are not available. This investigation reports on selected wood characteristics of old-growth trees from the Cordillera de Talamanca (approximately 2,700 m a.s.l.), Costa Rica. Tracheids occupy 93% of total volume; average tracheid length is 4 mm, wall thickness ranges 2.5–4.5 (–6.5) μm throughout the annual increment. Lignin content is between 33.6 and 34.7% excluding any lignin-like compounds. Cellular UV microspectrophotometry reveals that the compound middle lamella (CML) and S2 layer are characterized by a higher absorbance than is commonly observed in e.g. Pinaceae, and with a distinct gradient from S1 to S3. The carbohydrate (cellulose and hemicelluloses) composition reflects the typical proportions as found in other conifers. A low content of organic extractives explains the only moderate (white rot) to low (brown rot) natural durability of the heartwood against wood destroying fungi. The wood density (12% mc) ranges 0.5–0.68 g cm^-3; compression strength (44±2.38 MPa) and corresponding modulus of elasticity (8,600±1,720 MPa) indicate good elastomechanical properties. Accordingly, the wood is recommended for multiple indoor enduses. For exterior applications, effective protective measures and/or preservative treatment are required. Dedicated to Prof. Dr. Dr. h.c. mult. Walter Liese on the occasion of his 80th birthday     

Rebuilding fish stocks no later than 2015: will Europe meet the deadline?

Maintaining or restoring fish stocks at levels that are capable of producing maximum sustainable yield is a legal obligation under the United Nations Convention on the Law of the Sea (UNCLOS) and has been given the deadline of no later than 2015 in the Johannesburg Plan of Implementation of 2002. Here, we analyse stock assessment data of all major fish stocks of the Northeast Atlantic to determine whether Europe will be able to deliver on this commitment, which it has helped to bring about. The analysis shows that, if current fishing pressure continues, 91% of the European stocks will remain below target. If European ministers in charge of fisheries were serious about meeting their obligations, they would have to reduce drastically fishing pressure and halt fishing completely on some stocks. But even if fishing were halted in 2010, 22% of the stocks are so depleted that they cannot be rebuilt by 2015. If current trends continue, Europe will miss the 2015 deadline by more than 30 years. We argue that, from a legal perspective, such repeated enactment of fisheries management measures, which are incapable of maintaining or restoring B_msy, does not comply with the requirements contained in UNCLOS and may constitute a breach of the precautionary principle of European Community law.