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Improving phosphorus efficiency in rice: A strategy targeting complementary efficiency mechanisms

Matthias Wissuwa, Japan International Research Center for Agricultural Sciences (JIRCAS) 1-1 Ohwashi, Tsukuba 305-8686, Japan

04.10.2016 10:30 Uhr
04.10.2016 11:30 Uhr
Forschungszentrum Jülich, Gebäude 06.2 IBG-2, Seminarraum 406, 2.Stock


Phosphorus (P) is a non-renewable resource and P fertilizers are an increasingly costly input. Breeding more P-efficient rice varieties has therefore become an objective in breeding programs. Selection of modern varieties has typically been performed in high-fertility conditions with a primary focus on yield. This could have contributed to the loss of plant genes associated with efficient nutrient acquisition and utilization strategies. Our objective has been to screen diverse sets of rice gene bank accessions with the aim to identify new donor varieties for P efficiency traits and genes.
We previously identified Pup1, a major QTL for P uptake, and cloned the underlying gene OsPSTOL1, which has been introgressed through marker assisted backcrossing into major rice varieties. Pup1 breeding lines are now being tested across several Asian and African locations. However, phenotyping and genome-wide association studies (GWAS) of rice diversity panels suggest that additional P efficiency traits are present within the rice gene pool. Of particular promise are variation for the ability to take up more P per unit root size (root efficiency, RE) and for internal P utilization efficiency (PUE).
Improving RE would complement root-growth driven P uptake as controlled by the Pup1 locus and high RE was identified in only few traditional varieties from South-Asia. These are now used as donors in breeding and in physiological studies targeting underlying efficiency mechanisms such as root exudation or soil microbial interaction. Equally limited to traditional varieties is superior PUE, defined as biomass produced per P content. Physiological mechanisms for PUE such as P remobilization and allocation and potential consequences on photosynthetic efficiency will be discussed. 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 such complementary traits and genes into elite crop cultivars.

Contact person: Josefine Nestler, Ralf Metzner,