Detection of PVY extreme resistance genes in potato germplasm from the uruguayan breeding program

Breeding goals in potato programs encompass several important commercial traits such as market aspects (skin color, eye depth, shape), category use (fresh or processed), yield, crop duration, and pest and disease resistance. In light of medium- and long-term changes in trait requirements, breeders rely on a range of wild and commercial germplasm in their efforts to reach the multiple objectives that determine the success of a new variety. Readily selectable markers for the recognition of multiple introgressed traits in breeding populations would therefore be practical high-value tools. In subtropical countries, warm climate and the continuous cropping of potato promote high vector pressure and the spread of viruses, rendering seed certification schemes difficult.Potato virus Y (PVY) constitutes a constant problem in several developing countries and it was recently reported as a challenge for seed production in the U.S.A. and Spain, resulting in rejection of seed lots in certification programs. Here we report the simultaneous use of two molecular markers to identify genes for extreme resistance to PVY in the Uruguayan potatobreeding program germplasm. Simplicity and compatibility of the marker system (allele specificity) were emphasized in implementing a reliable and efficient procedure. Forty-four percent of the genotypes tested were shown to carry extreme resistance to PVY, in the majority of cases fromSolanum tuberosum ssp.andigena (Ry_adg). Furthermore, a single marker originating fromSolanum stoloniferum (M45) could be used to recognize both Ry_sto and Ry_adg. The molecular phenotype data corresponding to M45-Ry genotypes was in accordance with virus field exposure observations of resistance.     

Wood colour in Lapacho (Tabebuia serratifolia): chemical composition and industrial implications

This study is aimed at relating the colour of Tabebuia serratifolia (Bignoniaceae family) wood to its chemical composition and technological characteristics, such as hardness and gluing, important for the manufacture of wood flooring. Samples with standard wood colour and evident chromatic anomalies were subjected to CIELAB colorimetric and gas-chromatography analyses. Red and yellow wood colour is associated with the presence of lapachol and dehydro-α-lapachone, respectively, whereas large amounts of polyphenols were found in black parts, together with other quinone compounds. Wood is hardest where lapachol gives rise to a yellow chromatic zone (L1). Delamination tests have shown that polyphenols affect lamella bonding strength. The results may be used by the wood flooring industry to identify the chemical constituents of T. serratifolia according to its colour and foresee possible problems during the production process.     

Genetic variation for secondary seed dormancy and seed longevity in a set of black‐seeded European winter oilseed rape cultivars

Secondary seed dormancy in oilseed rape is a phenomenon that allows seeds to survive in the soil for many years without germination. Following soil cultivation, dormant seeds may germinate in subsequent years, and they are the main reason for the occurrence of volunteer oilseed rape plants in successive crops. Inheritance of secondary dormancy may be related to seed longevity (SL) in the soil. Genetic reduction in secondary dormancy and SL could provide a mean to reduce the frequency of volunteer plants and especially the dispersal of transgenic oilseed rape. The aim of the present study was to analyse secondary dormancy, germination rate and SL of 28 black‐seeded winter oilseed rape cultivars using in vitro laboratory tests. The material was tested in field experiments at six different locations in Germany in 2008/2009. Significant effects of the genotype and the location on all traits were found. Heritability was high for secondary dormancy (0.97) and moderate for germination rate (0.70) and SL (0.71). Results indicate that a selection for low secondary dormancy would be effective.     

Production of Lipase Using Cassava Peel and Sunflower Oil in Solid-State Fermentation： Preliminary Study

Full use of residues from industrial processes is a fundamental necessity of contemporary society, since it avoids impacts to the environment by using residues as inputs for other products of high economic and social importance. In this study, lipase production of the crude enzymatic extracts obtained by Aspergillus niger using cassava peel as substrate and sunflower oil as an inductor was investigated. The optimized cultivation temperature and concentration of inductor were determined using the response surface methodology. The two variables studied exercised influence in the production of lipase in the 95% level of confidence. The response surface obtained indicated that the conditions that maximize lipase activity production were 30.5 ~C and initial concentration of sunflower oil was 2.5% （w/w）. Through this analysis, it is evident that extremes in temperature and concentration of inductor tend to decrease lipase production, since low temperatures decrease metabolism and high temperatures may inactivate the lipase. Optimum lipase yield was 59.8 U/g of dry peel which was fermented for 60 h. Lipase production presents a peak of 61.3 U/g, at 72 h of fermentation. However, this value is statistically equal （p 〉 0.05） of the value of lipase activity obtained for 60 h and 84 h of fermentation.     

Characterisation of gluten-free pasta through conventional and innovative methods: Evaluation of the cooking behaviour

The rapid stiffening of a well-developed gluten network able to entrap swollen starch granules is a key factor for the high quality of durum wheat pasta during cooking. Good resistance and firmness, low stickiness and limited release of organic materials into the cooking water are quality traits of primary importance for traditional pasta. In gluten-free (GF) pasta, the formation of a scaffold of retrograded starch can be an alternative to gluten networking: it confers rigidity to the cooked product and reduces pasta stickiness and loss of soluble materials into the cooking water. In a previous paper, 14 commercial GF spaghetti samples were studied as uncooked products from a chemical, biochemical and physical point of view. The aim of this study was to determine the cooking behaviour of these samples. A durum wheat pasta was also included as reference. Suitable cooking conditions were adopted and different conventional and innovative evaluations (i.e. compression test, creep test) were performed as a function of cooking time. Different behaviours were evidenced, often related to the ultrastructural organization of the uncooked products. In particular, the creep test revealed to be very effective in discriminating among the properties of the different GF spaghetti.     

Presence of the <Emphasis Type="Italic">Eucalyptus</Emphasis> gall wasp <Emphasis Type="Italic">Ophelimus maskelli</Emphasis> and its parasitoid <Emphasis Type="Italic">Closterocerus chamaeleon</Emphasis> in Portugal: First record,geographic distribution and host preference

The Eucalyptus gall wasp Ophelimus maskelli (Hymenoptera: Eulophidae) and its parasitoid Closterocerus chamaeleon (Hymenoptera: Eulophidae) were observed for the first time in Portugal, in 2006 and 2007, respectively. Data on the distribution of O. maskelli in Portugal, differences in the susceptibility of two host species, Eucalyptus globulus and Eucalyptus camaldulensis, and parasitism by C. chamaeleon are given.     

Modelling the progress of Asiatic citrus canker on Tahiti lime in relation to temperature and leaf wetness

The combined effect of temperature (15°C, 20°C, 25°C, 30°C, 35°C, 40°C and 42°C) and leaf wetness duration (0, 4, 8 12, 16, 20 and 24 h) on infection and development of Asiatic citrus canker (Xanthomonas citri subsp. citri) on Tahiti lime plant was examined in growth chambers. No disease developed at 42°C and zero hours of leaf wetness. Periods of leaf wetness as short as 4 h were sufficient for citrus canker infection. However, a longer leaf duration wetness (24 h) did not result in much increase in the incidence of citrus canker, but led to twice the number of lesions and four times the disease severity. Temperature was the greatest factor influencing disease development. At optimum temperatures (25–35°C), there was 100% disease incidence. Maximum disease development was observed at 30–35°C, with up to a 12-fold increase in lesion density, a 10-fold increase in lesion size and a 60-fold increase in disease severity.     

Erratum to: Chemical quality of leachates and enzimatic activities in Technosols with gossan and sulfide wastes from the São Domingos mine

Journal of Soils and Sediments -