Wet direct-seeding is becoming an increasingly popular alternative to transplanting in Asian rice ( Oryza sativa L.) culture. Modern tropical rice cultivars, when direct-seeded, because of vegetative overgrowth and foliar N dilution during reproductive growth, often fall short of their biological yield potential. A field study using ‘IR72’ rice during the 1989 dry season in the Philippines evaluated the effect of late-season N top-dressing on canopy CO 2 exchange rate ( P n), growth and yield of a transplanted (TP), hillwise dibbled (DS) and broadcast seeded (BS) crop. In BS the higher seeding rate and absence of transplant shock led to a higher tiller number and leaf area index ( L) than in TP. Foliar N concentration decreased faster in BS because of more rapid growth. Late-season N top-dressing, broadcast or applied as foliar spray, increased foliar N concentration and P n, and led to greater spikelet number and grain-yield. Higher spikelet number was explained by reduced spikelet degeneration after top-dressing. Grain weight limited grain-yield when no N was applied, but was equal among N-fertilized treatments. Panicle number limited yield for TP, whereas grain number per panicle was more limiting for BS and DS. The P n during various reproductive growth stages was correlated with grain-yield, whereas dry-matter at maturity depended more on L. Harvest index ( hi) gave best correlations with foliar N concentration. The P n depended on both L and foliar N concentration, but the latter became more limiting as plant development advanced. It is concluded that late-season foliar N application raised grain-yield by enhancing the assimilate source through increasing foliar N concentration at a stage when it was limiting, and by enhancing the sink through the reduction of spikelet degeneration. Considering that both foliar N concentration and filled spikelet number are commonly limiting factors for BS yields, late-season foliar top-dressing may be a means specifically improve BS rice culture.