Effects of CO₂enrichment at different stages of panicle development on yield components and yield of rice (<i>Oryza Sativa</i>L.)

Abstract

Abstract Rice plants were enclosed in mylar film in the field and given CO2 enrichment at five stages of panicle development and grain filling. CO2 enrichment for 33 days before flowering increased grain yield by 30% over the control. This increase could be largely attributed to increased grain number and increased grain weight. Nine or 10 days enrichment at rachis-branch differentiation stage or spikelet differentiation stage increased grain yield by 10% ; this increase largely results from increased grain number. Two-week enrichment from reduction division to flowering had no over-all effects on grain yields. Thirty days enrichment after flowering increased grain yield by 10% over the control as a result of increasing grain weight and filled grain percentage. This experiment demonstrated that grain number per unit land area is more limiting to grain yield than grain filling.