Insufficient moisture during summer months limits UK sugar beet production more than any other single factor. Compared with potential production without stress, yield losses are on average 10%, worth ~£30M per year in the UK. Climate change models predict that summers will get hotter and drier, giving production areas with deep, water retentive soils a competitive advantage. To maintain productivity in the UK under these conditions, new, more drought-tolerant varieties are required. In addition, varieties that are less sensitive to the prevailing moisture supply should exhibit greater site-to-site and year-to-year yield stability, improving management decisions for growers and the processor. Currently, there is no mechanism in place for judging the relative drought performance of varieties entered into official variety trials, which are conducted across a range of sites, and there is no characterisation of the environmental conditions at each site. Therefore, the frequent change in genotype ranking depending on site remains a nuisance, which is ignored and only overall means are reported.
Outcomes / Key Message For Growers And Industry
The protocols and soils database have been established to routinely produce a score for each RL variety that indicates its performance for water-limited conditions relative to other varieties. However, it is unlikely at present that these scores would be published as part of a list of variety characteristics. This is because currently there are too few test sites, and few if any of these develop significant levels of stress. Hence, there remains no guide to growers which varieties would be better suited for light land and drought-prone conditions, which describes a large proportion of contracts in the UK in most years. Nevertheless, it is recommended to continue this evaluation of variety trial data that are already collected as part of the official variety trial programme: if a variety is tested over three or more years, and sufficient stress develops on at least three sites in each year, the minimum number of datapoints could be achieved to establish a drought sensitivity and yield stability ranking, and this information would be valuable to growers.