Impact of soil tillage on the robustness of the genetic component of variation in phosphorus (P) use efficiency in barley (Hordeum vulgare L.)

In order to improve the sustainability of agriculture it is imperative that the P-use efficiency of temperate cereal crops be improved. This can be achieved both by agronomic and genetic approaches. While many studies have demonstrated genotypic variation in P-use efficiency in a number of cereal species the robustness of this genetic variation with variation in environment is rarely considered. In this paper we describe an experiment in which we compare the P-nutrition of winter and spring barley genotypes grown in a field trial with contrasting cultivation treatments (conventional vs. minimum tillage) which have been developed over a number of years. We demonstrate that while there is significant variation between genotypes in their P nutrition that this variation is not comparable between cultivation treatments and only one winter barley genotype (cv. Gleam) has beneficial P-use efficiency traits in both cultivation systems. These data suggest that it may be possible to identify a genetic component to variation in P nutrition in barley but that a large interaction with environmental variables may limit the usefulness of any genes or markers discovered for improving P-use efficiency to the conditions under which the screening was performed.