Development of ‘RL Plus’: winter wheat variety performance in relation to site characteristics (HGCA Project Report No. 365)

D1 - Technical reports: non-confidential

Welham, S. J., Thompson, R. and Sylvester-Bradley, R. 2005. Development of ‘RL Plus’: winter wheat variety performance in relation to site characteristics (HGCA Project Report No. 365). Stoneleigh Home Grown Cereals Authority (HGCA).

AuthorsWelham, S. J., Thompson, R. and Sylvester-Bradley, R.
TypeD1 - Technical reports: non-confidential

This project developed RL Plus, an augmented version of the Recommended Lists for Cereals and Oilseeds, published by the HGCA on CD and the internet ( to provide the cereals and oilseeds industry with means of interrogating and analysing data from HGCA-funded variety trials. Given that RL Plus is fully documented and published in electronic form, it is not described further here. This report is confined to additional research analysing relative variety performance of winter wheat in terms of site

A spreadsheet was constructed of treated yields of winter wheat from 43 varieties across 506 trials (Recommended List, National List or BSPB trials) in the UK from harvests during 1992-2002. This included site information collected from the trials, and supplemented with the site location (OS coordinates), soil types, meteorological data and drought index derived during the project. Complete, or nearcomplete, data existed for 249 trials from harvests during 1993-2003. These data were used to investigate
factors associated with site variation in variety yields.

Data-mining techniques were used to identify site variables that explained variation in variety yields between sites. This information was used to build models to describe and predict patterns of variety variability due to site differences. Variation in variety yields could be modelled in terms of overall variety differences (43% variety variation accounted for), and variety interactions with large-scale trend due to geographic location (general climate, 16%), small-scale location trend specific to years (micro-climates, 14%), expected site yield (2%), late sown crops (crops sown on/after 30 October, 0.4%), sites with sandy or shallow soil (0.5%), sites with low soil K index (0.4%), differences between years (4.5%), differences between sites (unexplained by site variables, 2%), and other unexplained variation (18%). Further investigation suggested that other site variables, such as previous cropping, might also influence variety variability but that the relationship was local (differed between regions).

The results of the statistical analysis can be used to optimise use of the ‘Varieties on your Farm’ module of RL Plus. In general, geographic location appears to be the most important site variable influencing variation in variety yields across the UK. However, for particular varieties, the expected site yield, soil type or soil K index may be equally important.

Year of Publication2005
PublisherHome Grown Cereals Authority (HGCA)
Place of publicationStoneleigh
Web address (URL)
Open accessPublished as bronze (free) open access
Accepted author manuscript
Publisher's version
Output statusPublished
Publication dates
Online01 Mar 2005
Copyright licensePublisher copyright

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