The U.S. Gulf Coast has a relatively long growing season favorable for ratoon rice (
Oryza sativa L.) production. Ratoon rice is the regrowth crop after the main crop harvest. The application of gibberellin (GA) to the main crop late in development could increase ratoon-crop yield by promoting ratoon tiller vigor and ratoon crop earliness. This was a 3-year study conducted in 2003, 2004 and 2005 at the Texas A&M Agricultural Research and
Extension Center locations at
Beaumont and Eagle Lake, TX. Various cultivars were tested in field research plots. Gibberellin was applied at 10 g a.i. ha
-1 when the main-crop developmental stage was between 3-d post-flowering and soft-dough. The data was analyzed using a paired t-test of the median on each research block to evaluate GA-treated experimental plots compared to the untreated control plots. There is not a significant response of main-crop yield to gibberellin applications. The ratoon-crop yield is significantly increased by 286 kg ha
-1 over the untreated control with GA application. Whereas the GA treatment worked well on both conventional and hybrid rice, the very-early maturing, vigorous hybrids responded better in ratoon-crop yields. For these hybrids, the typical increases in ratoon yield were 400 to 700 kg ha
-1.