AGRONOMY AND SOILS Field Evaluation of Nitrophenolate Plant Growth Regulator (Chaperone) for the Effect on Cotton Lint Yield

Reports in the literature have been inconsistent relative to enhanced yields from applications of Chaperone (Asahi Co., Ltd.; Nara Prefecture, Japan), a PGR containing the nitrophenolates sodium 5-nitroguaiacolate (NaC7H6NO4) 1.25 g L -1 , sodium ortho-nitrophenolate (NaC6H4NO3) 2.5 g L -1 , and sodium para-nitrophenolate (NaC6H4NO3) 3.75 g L -1 . Two field studies were conducted to evaluate cotton yield response to foliar applications of Chaperone at early flowering. Study I was conducted in 2004 and 2005 at 28 locations in Texas, and assessed the commercially recommended rate of 0.43 g ai ha -1 compared with an untreated control. Study II was conducted at eight locations within Burleson County, Texas, from 2001 to 2005. The treatments consisted of Chaperone at 0.43 g ai ha -1 , 0.86 g ai ha -1 , and 1.72 g ai ha -1 compared with an untreated control. In Study 1, no differences in lint yield were observed between the Chaperone treatment and the untreated control. Regression analyses also failed to show a response from the Chaperone treatment at locations with lower lint yields relative to locations having higher lint yields. In Study 2, across all experiments, Chaperone at 1.72 g ai ha -1 increased lint yield by an average of 92 kg ha -1 (7.5%) over the untreated control lint yield of 1222 kg ha -1 . Chaperone applied in a single application at early flowering at 0.43 g ai ha -1 and 0.86 g ai ha -1 did not increase yield. Results of this research do not support the use of Chaperone in cotton at the current recommended rate.