Potatoes have a high demand for inorganic phosphorus (Pi) fertilisers, which they acquire and utilize less efficiently than many other crops. Hence, application of Pi-fertilisers for potato production can carry both financial and environmental burdens. To reduce the Pi-fertiliser burden, new methods for improving precision in the amounts, timing and location of Pi-fertilizer applications to potato crops are currently being sought. This paper describes a novel molecular-biological method to monitor the physiological status of a potato crop in the field based on global gene expression patterns in diagnostic leaves. The method has potential to diagnose incipient P-deficiency and, thereby, minimize Pi-fertiliser applications by allowing remedial applications of Pi-fertiliser to a growing crop.

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.

Billions of people worldwide consume insufficient calcium (Ca) or magnesium (Mg) for adequate health. Dietary Ca and Mg intakes can potentially be increased through crop biofortification. Recently, we reported sufficient natural genetic variation and heritability in a leafy crop plant (Brassica oleracea; C-genome, 1n=9; cabbage, cauliflower, kale etc.) to indicate that genetic biofortification is feasible in vegetable Brassica. We also reported loci affecting shoot Ca and Mg concentration (shoot-Ca and Mg). Here, we extend the previous study to explore the closely related species B. rapa (A-genome, 1n=10; Chinese cabbage, pak choi, a more tractable species genetically, and the amphidiploid species B. napus(AC-genome, 1n=19; canola/oilseed rape etc.). Wide variation in shoot/leaf-Ca and Mg occurs among all three species. Shoot/leaf-Ca and Mg is significantly and highly heritable. Quantitative trait loci (QTL) affecting shoot/leaf Ca and Mg concentration occur in potentially paralogous regions of B. oleracea and B. rapa. If confirmed, allelic variation at such loci could be used in biofortification breeding programs for vegetable Brassica. As genome sequencing and marker generation improves, it will be possible to resolve these (and other) putative loci to the gene level. Further studies on the regulation, interaction and function of these genes will enable us to understand Ca and Mg dynamics in plants.