Quantification of leaf stripe, Pyrenophora graminea, in barley seed by real-time PCR

In some years, large amounts of organic seed lots are discarded due to the presence of high levels of seed-borne diseases. In barley it is especially the presence of the fungal species Pyrenophora teres (barley net blotch) and P. graminea (barley leaf stripe), which causes rejection of seed lots. A real-time PCR method for detection and quantification of P. graminea has been developed

Molecular diagnostic methods can prevent unnecessary rejection of organic seed lots

In some years, large amounts of organic seed lots are discarded due to the presence of high levels of seed-borne diseases. In barley it is especially the presence of the fungal species Pyrenophora teres (barley net blotch) and P. graminea (barley leaf stripe), which causes rejection of seed lots. A real-time PCR method for detection and quantification of P. graminea has been developed

Effect of organic pig production systems on performance and meat quality

The present study was carried out to establish knowledge of consequence for setting up guidelines of importance for production of competitive organic pork of high quality. Performance and meat quality characteristics were compared between three organic pig production systems based on indoor housing with access to an outdoor area and a Danish conventional indoor system including 100% concentrate during the finishing feeding stage. The three organic systems used the following three feeding regimes: 100% organic concentrate according to Danish recommendations, 70% organic concentrate (restricted) plus ad libitum organic barley/pea silage and 70% organic concentrate (restricted) plus ad libitum organic clover grass silage, respectively. With exception of a slightly lower daily gain in organic pigs fed 100% concentrate, no significant difference was found in performance and meat quality characteristics compared with results obtained in the conventional system. In contrast and independent of roughage used, organic pigs raised on 70% concentrate had a significant reduction in daily gain (P < 0.001) compared with pigs raised on 100% concentrate, despite the fact that no difference in feed conversion rate was seen between the tested production systems. However, the percentage of leanness increased significantly in meat from organic pigs raised on 70% concentrate plus roughage compared with meat from pigs given 100% concentrate. This was reflected in higher yield (weight) of lean cuts and lower yield of cuts with high fat content from pigs fed 70% concentrate plus roughage. In general, organic feeding resulted in a significantly higher content of polyunsaturated fatty acids in the back fat (1.8%), which increased further when restricted feeding plus roughage (4%) was used. Restricted concentrate feeding gave rise to a decrease in tenderness compared with pork from pigs fed 100% concentrate

Nye diagnosemetoder til udsædsbårne sygdomme

Nye diagnosemetoder giver mulighed for at skelne udsædsbårne svampearter, som hidtil har været meget vanskelige eller umulige at adskille med konventionelle metoder

Quantitative relationships in the infection cycle of seed-borne net blotch

Seed-borne net blotch is a threat to organic barley seed production in Denmark because it often exceeds the recommended 15% contamination threshold in barley seed lots. This threatens the supply of organic barley growers with organically produced healthy barley seeds. The ORGSEED project aims at quantifying the links between initial seed contamination, primary seedling infection, disease severity during the growing season, yield parameters and new contamination of the harvested grains to improve decision support for handling net blotch contaminations in organic barley- and barley seed production. The harvested grains of spring barley varieties grown at several sites in Denmark in 2002 and 2003 were used as seed lots in subsequent trials in 2003 and 2004. The seed lots covered a range of contamination levels of seed-borne net blotch for each variety. Net blotch contamination level, 1000 grain weight and germination ability of the grains were determined and net blotch development during the growing season was visually assessed. The net blotch contamination level of harvested grains was highly positively correlated with net blotch severity at growth stage 70 (beginning of grain filling, gs 70). A general linear model explained 72% of the variation of grain infection based on effects of [variety x year] and [variety x year x net blotch severity at gs 70]. Net blotch severity at gs 70 was highly positively correlated with the net blotch contamination level of the seeds and a general linear model explained 71% of the variation of net blotch severity at gs 70 based on effects of variety and seed contamination level. The results indicate that the transmission efficiency of net blotch from the epidemic on the foliage to the grains differs among varieties and that the effects of seed contamination on net blotch development later during the season may be variety-specific as well. Net blotch disease severity was highly negatively correlated with 1000 grain weight and explained, together with [site x year] effects, 58% of its variation. Our results underline the importance of varietal resistance for seed health and suggest that the level of varietal resistance be included in considerations concerning the establishment of seed contamination thresholds

Maize seed orientation in the substrate and its influences on germination, seedling structure, and transmission of Fusarium moniliforme

A research paper on maize seed orientation.The percentage of seedlings emerging during the first 4 days after sowing and the mesocotyl length after 7 days in sand at 25°C was strongly influenced by the orientation of the seed in the seedbed. Maize seeds emerged faster when oriented vertically with the pedicel end facing down (VD) or horizontally with the embryal side facing up (HU). The mesocotyl portion of the seedling was shorter (t 1mm) when sown at HU and VD, providing a fast and easy emergence to the seedling. It was much longer (20mm) when the seed was oriented horizontally with the embryal side facing down (HD) and vertically with the pedicel end facing up (VU). We concluded that the length of the mesocotyl portion of the seedling varies with the orientation of the seed in the substrate at the same depth. The seeds sown in the orientation HU and VU disclosed a higher germination of 95 percent and 88 percent respectively, compared to the seeds sown in the orientation HD and VD which had 68 percent and 53 percent germination respectively. Seed to seedling transmission of Fusarium moniliforme was recorded at a ratio of 1:1 in the untreated seeds, and infection of the fungus was found in the third leaf lamina and other sections of 10 day old seedlings. This demonstrates for the first time the systemic development of F. moniliforme above the crown portion of 10 day old seedlings. Treatment with Thiram contact fungicide improves the germination of highly infected seeds and also reduces the seed to seedling transmission of F. moniliforme. The efficiency of this seed treatment depended on the orientation of the seeds in the seedbed