description
- The major outcome of the earlier analyses (Mackay et al, 2011) was the partition of trends in yield into environmental and genetic components, demonstrating that for cereals the greater part of the increase in yield since the 1980s was attributable to the uptake of improved varieties. In the absence of this genetic progress, on farm yields may even have declined. In contrast, for sugar beet and forage maize, other factors (presumed to be agronomy) also had a major impact on increasing yields over time. In addition these analyses demonstrated that the trials series could be used to provide information on: breakdown of disease resistance, differential sensitivity of varieties to seasonal weather, the accuracy of genomic prediction, and statistical bias in the analysis of the untreated trials, although none of these areas were explored in detail. In particular, variation among individual sites was not exploited in the 2011 study. The proposed research consists of the following components: 1. Update the historical trends analysis with ten additional years of data. This will begin with the crops studied previously (winter wheat, spring and winter barley, winter rape, sugar beet, forage maize) but will be extended to include additional crops, including potatoes, forage grasses and oats. 2. Incorporate local weather records into interpretation of site by site variation in variety performances and yield stability. This is the major extension over the previous study. Interpolation among local weather stations and model reanalyses can provide historical temperature records, and historical radar and satellite records can be used to provide local information on rainfall and solar irradiation. This will support analyses at a much finer time scale (at least daily) than the country-wide seasonal differences studied previously. 3. Incorporate other site specific variables into the analyses e.g. soil type and previous crop history. 4. Incorporate genetic information: use existing genetic marker data if possible and subject to permission (eg from the WAGTAIL consortium for winter wheat and from IMPROMALT for barley). At a minimum, this would allow study of the effect of major phenology loci (eg seasonal response and alternative height reduction loci) on variety stability. For wheat, we will also work with breeders able to provide small numbers (<10) of selected old and new varieties in their trials for at least two years to anchor the historical analyses in (1) to the present. 5. Study improvements in analysing the untreated trial series (the current method gives biased estimates of variety performance).