Effect of Flood Timing on Rice Grain Yield in a Drill-Seeded, Delayed-Flood Rice Production System.

In a drill-seeded delayed-flood rice production system, the permanent flood is applied just before rice begins tillering. The effect of flooding later or earlier on grain yield is unknown. A field experiment was conducted at LSU AgCenter H. Rouse Caffey Rice Research Station in Crowley, Louisiana, to evaluate rice grain yield at 5 different flood timings for nine rice varieties and hybrids: CL111, CL151, XL753, CLXL745, Cheniere, LaKast, Roy J, Mermentau, and Jupiter. Permanent flood was established 7 days after CL111 reached the 2-3 leaf growth stage and every 7 days thereafter. Mean grain yield across varieties from highest to lowest was 14 days (10,959 kg ha^-1), 7 days (10,388 kg ha^-1), 21 days (9,829), 0 days (9,503), and 28 days (9,287) after CL111 reached 2-3 leaf stage. Rice yield was affected by the flood timing by variety interaction. Five varieties (CL111, CL151, XL753, CLXL745, and LaKast) showed the highest yield when permanent flooding started 14 days after CL111 reached 2-3 leaf stage of development while the other 4 varieties (Cheniere, Roy J, Mermentau, and Jupiter) showed the highest yield when permanent was applied 7 days after CL111 reached 2-3 leaf stage of development. Preliminary data suggests that permanent flood establishment can be delayed up to 14 days after the 2-3 leaf stage of development for some rice varieties and hybrids without sacrificing grain yield.