Does reducing seed-P concentrations affect seedling vigor and grain yield of rice?

Aims Phosphorus (P) removed in grains causes losses of P from fields each year. Reducing grain P may therefore improve the P efficiency of cropping systems. This study quantified impacts of reduced seed-P concentrations on rice seedling vigor and final yields and investigated whether this was influenced by soil P supply or genotype. Methods Seed batches with P concentrations ranging from 0.9 to 3.5 mg g−1 were produced by growing rice in field plots ranging from severely P-deficient to fully fertilized and used in glasshouse and field experiments to investigate effects on seedling vigor and final grain/straw yield. Results 'Genotype by seed-P concentration' interactions were significant for seedling vigor but grain yield was generally not affected. This suggested some genotypes were sensitive to reduced seed-P concentration during the seedling stage while others with seed-P concentrations as low as 0.9 mg g−1 maintained rapid early vigor and high grain yield. Conclusions Results indicate it may be possible to reduce seed-P concentrations without having negative effects on seedling vigor or yield. The development of cultivars with reduced seed-P concentration, particularly if combined with rapid seedling root growth, could be a valid option to improve the sustainability of phosphate fertilizer use.