There are a number of chemicals being marketed as yield enhancers. Most of these are a combination of plant nutrients, various plant hormones, fermentation by-products, growth inhibitors, bacteria, etc. In 1986, studies were initiated to determine if in fact these chemicals would increase yields significantly or economically.

In 1986, Triggrr, Burst and PGR IV were applied at 8 ozs. per acre at early bloom (EB) and in combination with the yield enhancement rate of chlorodimeform of 4 applications of .125 lbs. per acre at weekly intervals beginning at the 5-6 leaf stage. Pix was applied at 16 ozs. and 8 ozs. at EB and 8 ozs. 2 weeks past EB. The 16 oz. rate of Pix at EB also was applied with the yield enhancement rate of chlorodimeform. In 1986, there were no significant differences between treatments and the untreated check, but there were differences among chemical treatments. The 16 oz EB Pix treatment was significantly better than the 8 ozs. of Burst at EB and the Burst + chlorodimeform or Triggrr + chlorodimeform. The PGR IV = chlorodimeform was also significantly better than the Burst + chlorodimeform and Triggrr + chlorodimeform.

There were no differences in any of the treatments in 1987. Since there were no differences in 1987, it can be assumed the low yields of Burst + chlorodimeform and Triggrr + chlorodimeform in 1986 were not the results of an antagonistic reaction.

The only difference in the two year average yield of chemical treatments in 1986 and 1987 was that the 16 oz. EB Pix and the chlorodimeform treatments were better than the 8 oz Burst treatment. The untreated check also was significantly better than the 8 oz. EB Burst treatment.

Multiple applications of Triggrr and PGR IV were studied in 1987 and 1988. There was no yield difference in a ozs. of Triggrr applied in a single application at EB or when it was applied in 4 applications beginning at matchhead square (MHS). Similar yields were obtained with PGR IV when 4 applications of 2 ozs. initiated at MHS or the 5-6 leaf stage or 6 applications of 1 oz. beginning at the 5-6 leaf stage. In 1988 Triggrr and PGR IV, 8 ozs., were applied two weeks after EB. The yields of these treatments were similar to the other treatments. The untreated check produced the highest two year average yield, 1190 pounds of lint.

These tests have resulted in inconsistent significant or economic yield increases resulting from the application of yield enhancers. These data also indicate where comparisons can be made that there was no difference between single or multiple applications.