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Although oilseed rape has become one of the most important oil crops in Europe, little is known regarding the viability of its seed under conditions of long-term storage. We report here an examination of oilseed rape seed longevity performed on a set of 42 accessions housed at the German ex situ genebank at IPK, Gatersleben. A comparison of germination between the accessions stored for 26 years showed that viability was in part genetically determined, since it ranged between 42 and 98%. An attempt was made to define the genetic basis of viability by subjecting a mapping population of doubled haploids to three artificial ageing treatments. Quantitative trait loci (QTL) were detected on six chromosomes: N6, N7, N8, N15, N16 and N18. The chromosomal locations of these QTL were compared with their syntenic regions in Arabidopsis thaliana in order to explore what genes might underlie genetic variation for longevity.

Herbicide-resistant Alopecurus myosuroides (Huds.) is an increasing problem in winter wheat in Western Europe. An increasing number of farmers need sequential herbicide applications to control biotypes with non-target-site resistance. Pre-emergence herbicides play an important and increasing role in resistance management. However, cases of pre-emergence herbicide resistance due to non-target-site mechanisms occur. This paper presents the results of bioassays to determine a reliable standard protocol for the diagnosis of resistance to pre-emergence herbicides in A. myosuroides. Testing was conducted to determine the influence on herbicide efficacy of two different soil types and three kinds of seed coverage, as well as analyses of the optimal assessment date. Additionally, dose-response experiments in soil-based pot bioassays under two growth conditions with pre-germinated seeds and a confirmatory field trial were carried out. Four different herbicides belonging to the HRAC-groups N, K3, and C2 were analysed (prosulfocarb, flufenacet, chlorotoluron, and metazachlor). The data showed no statistical influence of sandy loam or a mixture of sandy loam with sand as soil to the differentiation between susceptible and resistant biotypes. The seed coverage influenced the herbicide efficacy. Reliable results for all herbicides within the soil-based pot bioassay under greenhouse conditions at specific assessment dates were obtained. Suggested discriminating rates are 2000 g a.i. ha−1 for prosulfocarb (dat 14), 75 g a.i. ha−1 for metazachlor (dat 14), 2100 g a.i. ha−1 for chlorotoluron (dat 28), and 125 g a.i. ha−1 for flufenacet (dat 14). The pot assay was shown to be an appropriate procedure for the identification of pre-emergence herbicide resistance to prosulfocarb, metazachlor, chlorotoluron, and flufenacet in A. myosuroides. Consequently, a reliable, quick, and easy to handle bioassay which is required for high throughput screening was detected in the present study.

Alopecurus myosuroides is one of the most important grass weeds on arable land in Germany. For many years, it has developed herbicide-resistant populations. ACCase-and ALS-inhibiting herbicides, in particular, have lost significant efficacy. Two different mechanisms are commonly known to confer resistance to herbicides: target-site resistance (TSR) and non-target-site resistance (NTSR). In Germany, only approximately 5 to 10% of the herbicide-resistant black-grass populations have been reported to show TSR so far. To quantify the status and the distribution of TSR in Germany, 653 black-grass samples were collected between 2004 and 2012 all over the country. The samples were tested by bioassays and genetic analysis. Averaged over all tested samples, ACCase-TSR increased from 5.0% in 2004 to 54.3% in 2011. In 2012, the proportion of ACCase-TSR was lower than the previous years (38.5%). Similarly, ALS-TSR rose from 0.8% in 2007 to 13.9% in 2012. Regions with a high density of resistant black-grass samples were identified in the north and south of Germany. The data suggest a rapidly working selection of herbicide-resistant populations which may be due to current agricultural practices and the increasing use of herbicides acting on a single site.