The NL process is administered by the Food and Environment Research Agency within the UK government Department for Environment, Food and Rural Affairs. This is a legal requirement for marketing, and is aimed at ensuring that new varieties are genuinely new, that is they are distinct, uniform and stable (DUS) and have satisfactory value for cultivation and use (VCU). Varieties are first tested for 2 years in the National List (NL) trials after which they are assessed for acceptance onto the NL. In the United Kingdom (UK) there is a two-tiered testing system. Over 600 trials are conducted annually and cover a range of crops including wheat, barley, canola, chick peas, faba beans, field peas, lentils, lupins, oats and triticale. NVT is a national program of comparative variety testing in which current commercial varieties and breeding lines that are very close to commercial release are evaluated. In Australia the system is known as the National Variety Trials (NVT), and is funded by the Australian Government and growers through the Grains Research and Development Corporation (GRDC) and managed by the Australian Crop Accreditation System (ACAS) Limited.
#HOW TO CREATE SUBSETS WITH ASREML R SERIES#
In many countries it has long been the practice for plant breeding companies to submit potential new crop varieties for evaluation in series of field trials conducted by independent bodies. With this in mind, we offer a suggested reporting format that is user-friendly and contains far greater local information for individual growers than is currently the case. The information obtained from such an analysis may well be superior, but will only enhance industry productivity if mechanisms exist for successful technology transfer. In this paper we develop an approach for the analysis of crop variety evaluation data that is based on a factor analytic mixed model. In contrast, the factor analytic mixed model approach that is widely used in Australian plant breeding programs, has regularly been found to provide a parsimonious and informative model for V × E effects, and accurate predictions. In Australia, the variance component model has been found to be inadequate in terms of modelling V × E interaction, and the reporting of information at a regional level often masks important local V × E interaction. The variety predictions obtained from such an analysis, and subsequently reported to growers, are typically on a long-term regional basis. The most commonly used approach involves a variance component model that includes variety and environment main effects, and variety by environment ( V × E) interaction effects.
#HOW TO CREATE SUBSETS WITH ASREML R TRIAL#
Despite major advances in the statistical analysis of multi-environment trial data, such methodology has not been adopted within national variety testing programs. Within each program, data are combined across locations and seasons, and analysed in order to provide information to assist growers in choosing the best varieties for their conditions. Crop variety testing programs are conducted in many countries world-wide.
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