Selection of modern varieties has typically been performed in standardized, high fertility
conditions with a primary focus on yield. This could have contributed to the loss of plant genes
associated with efficient nutrient acquisition strategies and with adaptations to soil-related stresses.
Given the necessity to use scarce and increasingly costly fertilizer inputs more efficiently, while also
raising productivity on poorer soils, it will be crucial to reintroduce traits and genes associated with
efficient P acquisition and utilization into elite crop cultivars. JIRCAS together with collaborators
within the global rice research community has screened diverse sets of rice gene bank accessions with
the aim to identify new donor varieties for P efficiency traits and genes. After mapping of P efficiency
loci, candidate genes have been identified and characterized and tolerance mechanisms were
investigated physiologically. At various stages findings have been confirmed by field experiments to
assure practical relevance of research endeavors. One successful project recently identified the Pup1
gene enhancing P uptake from low-P soils (Gamuyao et al. 2012). Molecular markers diagnostic of the
superior Pup1 allele have been identified (Pariasca-Tanaka et al. 2014) and shared with breeding
partners throughout Asia and Africa, enabling them to conduct their own marker assisted selection
program with locally preferred varieties. Similar efforts are ongoing for novel P uptake and P
utilization genes. How such improved varieties may affect phosphate flows in agricultural systems will
be discussed.